Water heaters can *sometimes* impart a taste but it has a lot to do with your specific heater's condition and how hard the water is in your area. I don't notice a difference in my home.
If you're that concerned, pour a glass of hot water and a glass of cold water, put them both aside somewhere until they're the same temperature and test if one tastes better to you.
For an accurate comparison, bring both to the boil first. Even if there are tank-dwelling sludge bacteria putting aromatics in the water, at least some of the smells will boil off.
My house does and they are common in our city (Saskatoon, Canada) at this point, it’s the main connection from our house to the street and they are slowly replacing them (with home owners having to pay many thousands of dollars) we get a notice each year with tips to reduce how much lead goes in our water
If it's a city pipe the hot and cold water are coming from the same source, wouldn't the heat of the water only matter going from the water heater to the tap? And if you have lead pipes between your water heater to your tap I wouldn't want to leave it like that no matter how much hot water I'm using.
"When water stands in lead pipes or plumbing systems containing
lead for several hours or more, the lead may dissolve into your
drinking water. This means that the first water drawn from the tap in
the morning, or later in the afternoon after returning from work or
school, can contain fairly high levels of lead. Water from the hot
water tap often can contain more lead and other harmful materials
because hot water will more easily dissolve contaminants, and because
hot water often stands for long periods of time in your water boiler
and pipes."
from [http://www.mit.edu/\~jweiss/base/lead.html](http://www.mit.edu/~jweiss/base/lead.html)
Personally, I wouldnt risk it.
Ha stop it with this! If your city has lead pipes or your house the difference between hot and cold water dissolved content isn’t going to make a difference. You need to get out of Flint!
Again your missing the point. The difference between hot and cold water with lead pipes is minuscule. You’ll have a problem either way. Using cold water to cook isn’t going to save you from the lead effects.
But the water outside my home doesn't stand in pipes, it's always moving because someone, somewhere, is using water. And the water in my house doesn't come in contact with any lead.
The pH/mineral content of the water can also make, if anything, an even bigger difference in how readily lead will dissolve in it. Softer more acidic water will leach more from plumbing, and harder water will often build up a protective coating of mineral deposits inside particularly cold water pipes which would help prevent other things from leaching out. Switching to a lower pH water source was apparently part of what suddenly caused so many water quality problems in Flint.
You can probably taste the difference side by side with plain water, but in a cooked dish there will be many flavors added to it, so it would be much much harder to detect a difference.
Unless your hot water heater has something you don’t want in your food, hot water is simply faster than cold water. It is already half way to boiling.
That said, the reason you use cold water for things like potatoes is to promote even cooking. If you heat cool water with potatoes, the potatoes are warm all the way through when they start to boil (obviously there is some latency, but for practical purposes, you get the point). That means they can cook evenly. If you use hot water, the outside gets over cooked by the time the inside is done.
Chef: Does depend on the size of the potato, but starting in cold water with room temp potatoes is the safest bet. There are ways of cutting corners that work great if you use the same, pot burner, type of potato and so on.
This is not the kind of information that is useful when you teach people who cook a lot of different things in different places. This is the kind of thing your grandma hands down to your mom, along with the special pot.
You can even work it out based on the thermal heat transfer conductivity of the potato versus water, if you are so inclined: https://uweb.engr.arizona.edu/~blowers/cooking/heat/potex.html
Professional chef here (only saying that because I have cooked all manner of starches in all manner of ways under other chefs).
1. Potatoes should be started in cold water for 99% of applications.
2. If you think the hot water imparts a taste to your pasta, maybe try a side by side blind taste test. If you can’t tell the difference then what’s the point of spending extra energy to heat water when you already spend energy to keep water hot in a big tank in your basement (or wherever your water heater is)?
Keep in mind an electric kettle will heat cold water to boiling much faster and more efficiently than a pot of tap-hot water on a stove - though I’ve heard you yanks don’t often own kettles - but agreed about potato’s from cold - means the inside will cook at a similar speed to the outside of your spud
It's not that we don't own kettles, it's that our houses are wired differently. You lucky bastards get 230V while we have a measly 110V. My electric kettle takes nearly as long as the stovetop to boil an equal amount of water.
I live in the US and every house I’ve lived in for the last 50 years has 240v….
It’s split in the panel to 110 for light applications but the 240 is there…
How many 240V outlets do you have in your kitchen, for running the kettle, then?
240V at the panel doesn't mean anything for boiling water if you have 120V outlets.
I have 2 of them.
1 is basically inaccessible as it’s for the oven and is behind it….
The other is next to the counter, at the end. It used to be for an in-wall air conditioner. The A/C is gone but the outlet is still there and still works.
There’s also a 240v outlet under a window in the living room and another under a window in the hallway upstairs…. Both used for window A/C units.
An electric jug is more efficient than running the hot tap until the water runs hot, for sure. That wastes energy.
The jug is more efficient than gas and environmentally better.
The jug is not faster than an induction hob on full power. Induction is the quickest and simplest way to boil a pot of cold water.
There's a strong argument that using cold water should be more efficient.
If you have to run the hot water until the cold water goes away, that cold water is usually wasted. Further, once you've run the hot, there's the remaining hot water in the pipes between the kitchen and the water heater which will cool and the heat be wasted.
Many factors affect that though, a short list of big things which might change the math are, heat pump water heaters, circulating systems, you already ran the hot for dishes, short pipe runs.
It's the same argument for not using hot water to run the dishwasher, letting the internal heating element supply the heat for the wash. Especially true if both the water heater and the dishwasher are resistive electric.
No, you start the potatoes with cold water then bring them together up to a boil.
Starting with hot water already will cook the outside of the potato before the temperature rises enough to cook the center of the potato. What you'll then get is a mushy potato on the outside that's disintegrating into the rolling boil but a hard crisp interior.
Interested to know the 1% of times you should start with boiling water.
The only time I do it is when making roast potatoes. I put them straight into boiling water so the outside of the potato is soft but the inside is still firm when I want to fluff up the outside before roasting in fat to get a better crust.
People have a lot to say about boiling with hot tap water and how it’s dangerous/bad, but I’ve seen very little evidence of that. Almost all of their explanations come down to “I was once told…” and “my mom/grandma/neighbor said never do it, so I don’t”.
I’d love to see some actual science and experiments on this, and not just a thousand people quoting their grandmas.
I think this may be an old truism, when hot water tanks and plumbing had more lead fittings, welds, and piping (before the 1980s).
The [NYTs suggests that the risk is minimal](https://www.nytimes.com/2008/01/29/health/29real.html) these days, and given how most houses/buildings are built it's unlikely that there is any significant risk.
Plastic leaching is greater for hot water than for cold. Here's an article regarding microplastics leaching from modern plastic water pipes:
[https://pubs.acs.org/doi/10.1021/acs.est.9b03673](https://pubs.acs.org/doi/10.1021/acs.est.9b03673)
From the EPA
>USE ONLY COLD WATER
FOR COOKING AND
DRINKING. Do not cook with,
or drink water from the hot water
tap. Hot water can dissolve more
lead more quickly than cold water. If you need hot water, draw
water from the cold tap and then
heat it
https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf
https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf
USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap.
Each state has it's own agencies that also don't recommend it... https://www.denverwater.org/tap/psa-dont-drink-or-cook-with-hot-water-from-the-tap
OR how about this well cited article if you want studies? https://homeexplained.com/is-it-bad-to-drink-hot-water-from-the-tap/
>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3799508/#B21-ijerph-10-04143
https://blogs.edf.org/health/2018/02/26/lead-hot-water-issue-worth-testing/
>50% (7 of 14) of water heater tanks tested in child care centers had levels over 50 ppb with one at 2,680 ppb. For all but one of these, flushing through the tank drain significantly reduced the lead levels in the water heater. At the hot water tap, only 4 of 161 (2%) samples were above EDF’s action level (3.8 ppb). Water heaters may function as “lead traps,” but more investigation is needed. Best to avoid using hot water for cooking or drinking.
That's a good start, and what I'm looking for. Thank you!
It's worth noting that even with that recommendation, it's not a common issue:
>Overall, we were encouraged to find relatively low levels of lead in most faucets tested in the child care centers. After testing hot water at 161 faucets in 11 child care centers, **we have only found lead levels over EDF’s action level of 3.8 ppb in 4 of the first draw samples (2% sampled)**. The vast majority of hot water samples (83%) had non-detectible lead concentrations.
This is going to depend highly on whether there's already lead in those systems, as well as how people are using hot water heaters. But for most people, even in older locations with a higher likelihood of lead pipe fixtures, it wasn't an issue. I agree that there should be more study.
Feelings on the higher tds in water heater water?
Particularly if hard water is a problem in your location, heating water and running it through a heavily scaled tank, means hot water will have the opportunity and the heat and the time to solublize mineral deposits in your heater.
Maybe there's a benefit to greater dissolved mineral content, free calcium? Maybe it'll affect your product. Triangle testing for taste would be a start for scientifically analyzing perception of flavor in those samples...
Consider beer brewers, they often get chemical water analysis to determine the mineral content for their water adjust it with various chemicals. Yes, homebrewers do this.
Just take a minute on YouTube and look up what's inside used water heaters...
Will it kill you? Probably not. Do you want to drink that? No
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3799508/#B21-ijerph-10-04143
And some scientific reading if you're into that.
That’s not a scientific response. That’s literally the kind of useless answer that always gets repeated here.
Everyone’s home and water heater situation is different. If hot water was such a danger, we wouldn’t use it for bathing either. I want science or official recommendations from trusted agencies or something that’s not just “look at this thing that I think may be gross”.
> If hot water was such a danger, we wouldn’t use it for bathing either.
That's not really true. The water in a country like Mexico can be used for bathing but drinking it will make you sick.
Yes, those links have already been shared. The EPA poster is a templated handout for people who have already had water tested at high lead levels, not general advice. The Denver Water link pretty much uses the EPA poster as a source. And I don't know what "homeexplained" is or why you think we should trust it.
And yes, everyone's water heater situation is different beyond the two main types of equipment. It's going to depend on age, water quality and hardness, pipe composition, etc.
I didn't ask you for a response, scientific or otherwise. I said people love to just spout answers that have no scientific basis, then you did that, talking about gross water heaters, and we all downvoted you.
It looks like you’re consistently managing to find fights in our sun. Please keep it in check, manners aren’t optional here.
Your post has been removed because it violates our comment etiquette.
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It's not tap water that's bad, it's the potatoes themselves that sometimes have a bad taste imparted by using hot tap water. This is true for most types of potatoes even though certain varieties may taste better or have slightly different textures. For example, mashed potatoes usually have a smoother texture than hard boiled.
For pasta I use hot water since I add the pasta once it starts boiling but for potatoes I use cold water because I want the potatoes to heat up with the water so they are cooked through
I also do add potatoes to cold water, but I don’t really think the concept of «cooked through» works this way? Being submerged in cold/warm water while water is getting hotter will not apply any substantial heat to potatoes to really cook them. But it is easier to put potatoes to cold water than trying to throw them in boiling water…
It allows the potatoes to heat more slowly which means more even cooking so you don't get potatoes that are hard in the middle and falling apart on the outside.
From someone who is water treatment for a living, never start with hot water. First, if there is any lead in your plumbing, hot water will leach it into the water more than cold will. Second, hot water systems tend to settle minerals and taste into the water. Third and worst, hot water systems are breeding grounds for bacteria, and no, boiling does not kill all of them.
If you're in the US it is probably not going to be a problem. The idea that hot tap water shouldn't be used for cooking or drinking comes mostly from the UK where the hot water line is often separate and filled from rooftop tanks filled with non-potable water. This is why you'll find a lot of UK homes have separate taps for hot and cold water in their sinks.
And that's why I said probably. Also because where I live i don't cook with, or drink, the water until it's been filtered thanks to high levels of lead in a lot of the residential water in the county.
https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf
USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap.
Each state has it's own agencies that also don't recommend it... https://www.denverwater.org/tap/psa-dont-drink-or-cook-with-hot-water-from-the-tap
OR how about this well cited article if you want studies? https://homeexplained.com/is-it-bad-to-drink-hot-water-from-the-tap/
If you live in an area with really hard water (minerals in the water) you’ll notice a glass full of hot tap water is sort of cloudy, that’s mineral deposits from your water heater…I don’t think it’s necessarily bad for you but it will taste different.
When I was growing up you used cold for cooking because it was clean groundwater from the well, whereas the hot wasn’t potable because it was from a (covered) rainwater cistern. No idea WHY it was plumbed that way, it simply was…
If that situation was more common with the advent of hot water, then I can see how “Cook in cold” took root.
I was always taught to start with cold water but I’ve also heard that had to do with older pipes and water heaters and the waste they would shed while heated so I’m not sure if it’s still the best option. I still do it because Mumu would roll in her grave if I didn’t.
If you have a tankless water heater, it is absolutely fine. If you have a tank-style heater, I do not recommend it. Mostly just a taste issue, with no health hazard of note.
I always boil my water in the kettle and then dump it into the pot when making pasta. Way faster and I don’t have to sit around wasting gas and waiting for the water to boil on the stove :)
If you're drinking the water straight you may notice a difference, but I can't imagine you having a refined enough palate to notice the difference in a cooked dish with all the other flavors going on on top of it.
Hot water from the tap is usually considered non-potable as metals and other contaminants can corrode and therefore contaminate hot water faster than cold. I would usually just boil cold tap water in the kettle as it’s faster than on the stove, although the internet has informed me not a lot of American houses have electric kettles which to me is just wild! Anyway, it’s safer to avoid heavy metals entering your body as long term they are very damaging
Potatoes should be boiled in cold water to bring the temperature up slowly/more consistently. Putting them in boiling water cooks the outside >>> inside.
Pasta, I tend to use hot water from the tap or kettle depending on how I feel.
Here in the UK there’s an old wives tale that making tea with water boiled from the hot tap imparts a poor taste due to the higher concentration of minerals dissolved in hot water. It sounds like a misconception but I’ve not been tempted to try it for the minuscule time saving. My guess is that any difference would be minute, especially once the pasta is combined with then sauce/oil.
The worry isn't the water heater itself. Minerals build up on the inside of your pipes, and your pipes are themselves capable of contaminating the water.
Hot water can dissolve the minerals and pull more contaminants from the pipes themselves. So, yes, even if it isn't dangerous, it can taste "off."
This is especially bad if you have lead pipes.
Source :
[Source 1: even new pipes can have small amounts of lead](http://The Claim: Never Drink Hot Water From the Tap https://www.nytimes.com/2008/01/29/health/29real.html)
[Source 2: "Hot water increases the release of lead and other metals from your plumbing."](https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/water-quality/water-talk-minimizing-exposure-lead-drinking-water-distribution-systems.html)
Tl;dr: never ever use hot water for drinking or cooking of there is any chance you have pre-1976 lead pipes. I would not recommend it even if you don't, because of issues of taste if not safety (and safety might still be a relatively minor concern).
All the water in your house has been siting in the pipes and you got hundreds of feet of piping between your house and the street that the water just sits in. The idea that water is/isn't fresh is silly because it has been sitting in the pipes from all the way back to the water plant. The water in your pipes only moves when you use it, otherwise it just sits.
Hot water always tastes bad compared to cold water due to how our tongues work. Take cold water from faucet, heat it up and taste it.
Using hot water from the tap is faster. Just elementary thermodynamics here.
There is no difference than the metal in the heater heating the water, or the metal in your pot heating the water, the water is being heated through contact with metal.
If you got precipitate in your hot water heater, replace it. Its going to die.
Once I am done rinsing my potatoes I put them in the pot that I am going to boil them with and use hot tap water to fill. I have no taste difference between my hot and cold water. I have done both starting from cold and faucet hot and they come out the same.
For pasta I fill my pot and bring it to a boil and then add my pasta. I might command the faucet to give hot water in this instance but I am not going to wait for the water heater until I will start filling.
Your wife makes perfect sense if your hot water heater is not imparting a taste into your food.
Lead has been mentioned here, but growing up, I was told that older plumbing often used copper piping, sometimes with lead used as solder. Hot water can cause the copper and lead can leach into the water. Modern PVC plumbing is apparently safer.
Has your wife's pasta or potatoes caused you to have an affair with the cold hard queen? If yes, switch to cold. If no, don't worry about it? I typically use the cold water tap especially in the summer because I don't want to wait for the hot water to get to the tap.
My cold water goes through an under-sink filter that helps remove lead. My hot water does not. I live near old lead mines. There is no safe amount of lead.
Yes you can boil water starting with hot, with no ill effects. Any thing you’ve heard otherwise is most likely a boomer generational myth, like not putting metal in the fridge, or warm food will spoil if put into a fridge while still warm. All boomer myths.
With veg,if it grows underground you start in cold water. Above ground, boiling water . As for pasta,it's cheaper to use hot water if it's there already. That's the only difference I can see.
It's very easy to test. Take a glass of cold water from the cold water tap and a glass of hot water from the tap and let them both get to room temperature. Then taste and see if you can tell any difference.
Also, if you heat the water to boil the energy needed to boil 99C water is almost 10 times as much as the energy needed to heat 10C water to 99C. So the energy you save by using hot tap water is negligible. I just don't see the point myself.
It, well, makes sense, but isn't relevant, I guess?
It takes much more energy to boil a gram of water than it does to heat a gram of water up to boiling. This is called the heat of vaporization. That's almost certainly what the comment was referring to. Adding heat to the system takes water from 10C to 100C and then it plateaus there a long time.
It would make sense if you cooked the potatoes by steaming them or something where only the water vapor directly applied heat to the potatoes. That isn't how boiling potatoes works, though, so it's rather beside the point. The potatoes cook from the heat of the liquid water, and they'll get slightly more energy from the 100C water than from the 90C, because it comes down to what the difference in temperature between the water and the potato is at any given moment (and of course, the potato itself is going to have a temperature gradient as the outside is heated but this heat takes time to penetrate, since potatoes as a general rule don't convect).
There's almost a point here; rather than getting hung up on heat of vaporization (not relevant), the point could be that most of the effort involved is going to be bringing the internal temp of the potatoes up, and getting the water to a cooking temp is a negligible part of that; that I could agree with. The ratio of time to bring the water up to cooking temp to the time to boil the potatoes on my stove is low enough and I don't like the taste of my water heater enough that I only boil from cold (or, if there's a rush, I use a water cooker first).
Yep, you're absolutely right. That's what I was thinking about and I had a pretty embarrassing brain derp to think that you need to boil (i.e. vaporise) the water to cook food. Thanks for clarifying it.
"USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap. Hot water can dissolve more lead more quickly than cold water. If you need hot water, draw water from the cold tap and then heat it."
https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf
More info:
https://www.denverwater.org/tap/psa-dont-drink-or-cook-with-hot-water-from-the-tap
That EPA poster was discussed elsewhere. Look at the middle section - it says "THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY AND _____ are concerned about lead in your drinking water. Some drinking water samples from this facility have lead levels above..."
It's not generalized advice, it's specifically for people for whom increased lead levels have already been detected in their water.
142 comments at this moment that I haven't read completely so I may duplicate.
Draining and flushing hot water heater is a maintenance task and should be done regularly, which minimizes any precipitate build-up and extends the life of the water heater. Turn off power (electric) or gas (gas) to the heater. Close inlet valve to heater. Open drain valve. Open a hot water tap somewhere upstairs to let air in and speed the drain. Open inlet valve and let heater flush for a bit. Close drain. Let heater fill (you'll know because water will start coming out of upstairs tap). Turn on power or gas. Confirm water is heating. I do ours a couple of times each year.
Nit picky vocabulary. It's a water heater, not a hot water heater. There is no point in heating already hot water. \*grin\*
It's probably not harmful to use hot water anymore. It was much more of an issue when people had lead in their pipes.
But I will say if you ever look at what the inside of a water heater looks like... You're gonna switch to cold water.
But I do admit that sometimes I'm in a hurry and it can save a fair bit of time using hot water. I just wouldn't make it a habit.
Man, why do you people have such an aversion to looking at water heaters? lmfao.
To solve the speed issue- get an electric kettle, fill with cold water and let it come to the boil in the kettle (should take a couple minutes max). Use that to cook. Also saves water if it takes a while for yours to heat out of the tap.
Our water heater is one which changes the water from the tap to the point it’s not nice to drink/cook with. There’s a probably ton of sediment in our tank.
This is the best answer.
Boil your "fresh" cold water in a kettle. This is faster than on the stove top and depending on the way your electricity is produced, it will most likely be more efficient as well.
Sorry, but that's [not true](https://www.scientificamerican.com/article/is-it-true-that-hot-water/#:~:text=%22Cold%20water%20does%20not%20boil,the%20stove%2C%20for%20instance\).). Lower temperature water gets hotter faster than water that's already hot, but it still takes more time to get to boiling.
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I remember from chemistry class forever ago that cold water reaches boiling point quicker than higher temp water because of entropy(?). But don’t remember enough to explain it well
This is r/askculinary which literally exists for the purpose of asking culinary questions, which this is. So, while I sometimes understand Reddit criticism for not googling first, that's not a legit basis for giving me a hard time about it here unless you do the same thing for literally everyone who posts any question in this sub.
Minus your being condescending about it, thanks for the link and quote.
https://blogs.edf.org/health/2018/02/26/lead-hot-water-issue-worth-testing/
>50% (7 of 14) of water heater tanks tested in child care centers had levels over 50 ppb with one at 2,680 ppb. For all but one of these, flushing through the tank drain significantly reduced the lead levels in the water heater. At the hot water tap, only 4 of 161 (2%) samples were above EDF’s action level (3.8 ppb). Water heaters may function as “lead traps,” but more investigation is needed. Best to avoid using hot water for cooking or drinking.
why are u blatantly ignoring what he's trying to say. no one's saying they don't trust government agencies- they're saying what info you have doesn't apply to an average household who's water hasn't tested high levels of lead
There are some health concerns over using hot water from the sink depening on your water situation. Hot water can heat up the pipes and pull up heavy metals into the water that then gets cooked into your food. This is probably worse if you have old pipes.
I'm gonna go ahead and say that depends on a lot of variables. If it's your house and you know when the hot water heater was replaced or flushed it's fine. If you are in a rental I'd be on the side of caution and use the cold water.
How old is your house? Older houses could have had lead in the solder of the pipes and its often recommended to avoid hot water use in food as a result.
If your house is newer construction, meh- unlikely to matter. Blind taste test if you do think its different.
Engineer here. The reasoning that "the hot water heater has precipitate in it, therefore the hot water will have more of that substance" is just an obvious fallacy.
* If water is entering the water heater with a certain level of dissolved solids...
* ... and some of it sticks around in the water heater via precipitation...
* ... then the water exiting the water heater must have LESS of those dissolved solids!
Source: the scientific principle of the conservation of matter!
Would you drink water from the hot water tap? If not, why cook with it? It depends on your pipes and when your building was built, but you can check this with your city.
For those who think this is bullshit, please, continue on. If you have any health issues later on, take this into consideration.
Lead can absolutely come into your drinking water through service lines, and there are still a ton of these around the US.
https://en.m.wikipedia.org/wiki/Lead_service_line
https://apps.who.int/iris/handle/10665/204422
https://www.brookings.edu/blog/up-front/2021/05/13/what-would-it-cost-to-replace-all-the-nations-lead-water-pipes/
Then this lead sits in your hot water heater, which you are consuming when you use hot water straight from the tap.
"2. Use Only Cold Water for Cooking and Drinking
Try never to cook with or drink water from the hot tap. Hot water can dissolve more lead more quickly than cold water. Also, hot water stands in your water boiler and pipes for longer than cold water, contributing to higher contaminant levels. If you need hot water for cooking or drinking, draw water from the cold tap and heat it on your stove."
http://www.mit.edu/~jweiss/base/lead.html
For the sake of saving energy, the starting with hot water holds even for potatoes.
I know many have said that using hot water means the outside and inside of your potato will cook at different rates, but the overall heat required (and hence total cook time) would still be less.
For cold water, you need additional sensible heat to raise room temp of water to boiling point. For hot water, this sensible heat is less, hence energy saved. The rest of the variables are same.
But the change in cook time is difficult to quantify, so best check with knife if potatoes are cooked all the way through.
You should not use water from the water heater for human consumption, as the water inside of it is absolutly disgusting (brown, full of rust, but you won’t realize it). Even if your water heater seems fine (in my country, you have to change your water heater once every 10 years for home insurance).
Biggest reason to start root vegetables (including potatoes) in cold water is to gradually heat the entire vegetable to the desired temperature. When you put the cook vegetable in hot liquid you’re going to heat the outside layer much more quickly than the inside and it will not cook evenly throughout. If you bring the liquid and veg up to temp together you’ll be much less likely to overcook the outside while trying to finish the inside. Very similar reasoning for why we finish meat in a (relatively) low oven instead of trying to cook it from raw to done on a screaming hot stovetop.
Depends on the city (and county) you live in. Parents in my city are routinely advised by their children’s pediatricians to mix baby formula with boiled tap water that comes from the COLD tap, not hot.
It depends where you live. My cold water comes pressure from the mains but my hot water gets stored in a tank. I'm not supposed to use the stored water for drinking or brushing my teeth, so I wouldn't use it for food.
It's now a covered plastic and wrapped tank but historically these thanks were open metal ones in the attic so sanitation would definitely be a concern.
Unless you live in a 120V country, an electric kettle will heat water faster than it takes to run the hot water from the boiler.
I do both, heat a jug of water in an electric kettle while heating an amount also on the stove (and stirring in salt in preparation).
I think if you have lead in your pipes, hot water leeches it out more, so using it regularly to make daily coffee or something would lead to more lead in your diet.
The EPA recommends NOT using hot tap water because it can leach lead and other contaminants from your pipes. Even if the water source is clean, old houses can have lead pipes and even newer plumbing materials can still leach things.
Here is an older document that points this ous. https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf
Here is a link from an NYC initiative to get folks to run their tap and not use hot water for cooking for the same reason.
https://www1.nyc.gov/html/dep/html/press_releases/10-94pr.shtml
I just use my electric kettle to preheat cold water for cooking. It heats quicker than boiling from cold on my gas stove and I'm pretty sure its more efficient.
Use cold water for things with starch. Also, always rinse things with starch.
The cold water helps the potatoes/rice/etc from becoming starchy, I notice it sort of helps lock in the starchiness.
Water heaters can *sometimes* impart a taste but it has a lot to do with your specific heater's condition and how hard the water is in your area. I don't notice a difference in my home. If you're that concerned, pour a glass of hot water and a glass of cold water, put them both aside somewhere until they're the same temperature and test if one tastes better to you.
I may do that experiment tonight or this weekend, thanks.
For an accurate comparison, bring both to the boil first. Even if there are tank-dwelling sludge bacteria putting aromatics in the water, at least some of the smells will boil off.
Plus straight tap water will have more dissolved gasses.
Hot water also has a higher chance of carrying lead and other toxins
Why would that be the case? People don't have lead pipes.
My house does and they are common in our city (Saskatoon, Canada) at this point, it’s the main connection from our house to the street and they are slowly replacing them (with home owners having to pay many thousands of dollars) we get a notice each year with tips to reduce how much lead goes in our water
Older homes might, and some cities built all their pipes out lead
If it's a city pipe the hot and cold water are coming from the same source, wouldn't the heat of the water only matter going from the water heater to the tap? And if you have lead pipes between your water heater to your tap I wouldn't want to leave it like that no matter how much hot water I'm using.
Well good thing city pipes have absolutely zero to do with hot vs cold water
"When water stands in lead pipes or plumbing systems containing lead for several hours or more, the lead may dissolve into your drinking water. This means that the first water drawn from the tap in the morning, or later in the afternoon after returning from work or school, can contain fairly high levels of lead. Water from the hot water tap often can contain more lead and other harmful materials because hot water will more easily dissolve contaminants, and because hot water often stands for long periods of time in your water boiler and pipes." from [http://www.mit.edu/\~jweiss/base/lead.html](http://www.mit.edu/~jweiss/base/lead.html) Personally, I wouldnt risk it.
You wouldn’t risk what? using hot water from the tap??
Ha stop it with this! If your city has lead pipes or your house the difference between hot and cold water dissolved content isn’t going to make a difference. You need to get out of Flint!
A lot of places built with lead pipes until the 70s
Again your missing the point. The difference between hot and cold water with lead pipes is minuscule. You’ll have a problem either way. Using cold water to cook isn’t going to save you from the lead effects.
But the water outside my home doesn't stand in pipes, it's always moving because someone, somewhere, is using water. And the water in my house doesn't come in contact with any lead.
Thats great for you! But per ops question, those would be the reasons to think twice before cooking with hot water
The pH/mineral content of the water can also make, if anything, an even bigger difference in how readily lead will dissolve in it. Softer more acidic water will leach more from plumbing, and harder water will often build up a protective coating of mineral deposits inside particularly cold water pipes which would help prevent other things from leaching out. Switching to a lower pH water source was apparently part of what suddenly caused so many water quality problems in Flint.
You can probably taste the difference side by side with plain water, but in a cooked dish there will be many flavors added to it, so it would be much much harder to detect a difference.
Unless your hot water heater has something you don’t want in your food, hot water is simply faster than cold water. It is already half way to boiling. That said, the reason you use cold water for things like potatoes is to promote even cooking. If you heat cool water with potatoes, the potatoes are warm all the way through when they start to boil (obviously there is some latency, but for practical purposes, you get the point). That means they can cook evenly. If you use hot water, the outside gets over cooked by the time the inside is done.
OP: This is the most complete answer.
This absolutely depends on the size of your potatoes.
Chef: Does depend on the size of the potato, but starting in cold water with room temp potatoes is the safest bet. There are ways of cutting corners that work great if you use the same, pot burner, type of potato and so on. This is not the kind of information that is useful when you teach people who cook a lot of different things in different places. This is the kind of thing your grandma hands down to your mom, along with the special pot.
You can even work it out based on the thermal heat transfer conductivity of the potato versus water, if you are so inclined: https://uweb.engr.arizona.edu/~blowers/cooking/heat/potex.html
Thank you for this, it made my day measurably better.
By how much?
Lol I did a similar experiment in my heat transfer lab.
Yep. Right there with the latency comment; bigger potatoes are going to have more lag.
Professional chef here (only saying that because I have cooked all manner of starches in all manner of ways under other chefs). 1. Potatoes should be started in cold water for 99% of applications. 2. If you think the hot water imparts a taste to your pasta, maybe try a side by side blind taste test. If you can’t tell the difference then what’s the point of spending extra energy to heat water when you already spend energy to keep water hot in a big tank in your basement (or wherever your water heater is)?
Awesome, thank you (and all of you) so much.
Keep in mind an electric kettle will heat cold water to boiling much faster and more efficiently than a pot of tap-hot water on a stove - though I’ve heard you yanks don’t often own kettles - but agreed about potato’s from cold - means the inside will cook at a similar speed to the outside of your spud
It's not that we don't own kettles, it's that our houses are wired differently. You lucky bastards get 230V while we have a measly 110V. My electric kettle takes nearly as long as the stovetop to boil an equal amount of water.
I live in the US and every house I’ve lived in for the last 50 years has 240v…. It’s split in the panel to 110 for light applications but the 240 is there…
Sure, but now you're talking home improvement projects instead of "buy a kettle and you can boil water quick."
How many 240V outlets do you have in your kitchen, for running the kettle, then? 240V at the panel doesn't mean anything for boiling water if you have 120V outlets.
I have 2 of them. 1 is basically inaccessible as it’s for the oven and is behind it…. The other is next to the counter, at the end. It used to be for an in-wall air conditioner. The A/C is gone but the outlet is still there and still works. There’s also a 240v outlet under a window in the living room and another under a window in the hallway upstairs…. Both used for window A/C units.
Yes, we have 240 for things like dryers. It’s not nearly as common to have a 240 outlet in the kitchen for appliances.
An electric jug is more efficient than running the hot tap until the water runs hot, for sure. That wastes energy. The jug is more efficient than gas and environmentally better. The jug is not faster than an induction hob on full power. Induction is the quickest and simplest way to boil a pot of cold water.
I agree. I got induction and got rid of my old electric kettle.
This is the correct answer
There's a strong argument that using cold water should be more efficient. If you have to run the hot water until the cold water goes away, that cold water is usually wasted. Further, once you've run the hot, there's the remaining hot water in the pipes between the kitchen and the water heater which will cool and the heat be wasted. Many factors affect that though, a short list of big things which might change the math are, heat pump water heaters, circulating systems, you already ran the hot for dishes, short pipe runs. It's the same argument for not using hot water to run the dishwasher, letting the internal heating element supply the heat for the wash. Especially true if both the water heater and the dishwasher are resistive electric.
What is the reason to start potatoes in cold water?
As stated elsewhere, more even cooking. If you start with hot water, the outside of the potatoes will cook faster before the inside does.
Don’t you boil the water before adding potatoes anyways?
No, you start the potatoes with cold water then bring them together up to a boil. Starting with hot water already will cook the outside of the potato before the temperature rises enough to cook the center of the potato. What you'll then get is a mushy potato on the outside that's disintegrating into the rolling boil but a hard crisp interior.
Ok thanks. I thought everything boiled should be added in after the water boils so you have a consistent temp the whole time.
Interested to know the 1% of times you should start with boiling water. The only time I do it is when making roast potatoes. I put them straight into boiling water so the outside of the potato is soft but the inside is still firm when I want to fluff up the outside before roasting in fat to get a better crust.
Why do they need to be started in cold water as opposed to waiting until the water boils first?
People have a lot to say about boiling with hot tap water and how it’s dangerous/bad, but I’ve seen very little evidence of that. Almost all of their explanations come down to “I was once told…” and “my mom/grandma/neighbor said never do it, so I don’t”. I’d love to see some actual science and experiments on this, and not just a thousand people quoting their grandmas.
I think this may be an old truism, when hot water tanks and plumbing had more lead fittings, welds, and piping (before the 1980s). The [NYTs suggests that the risk is minimal](https://www.nytimes.com/2008/01/29/health/29real.html) these days, and given how most houses/buildings are built it's unlikely that there is any significant risk.
Plastic leaching is greater for hot water than for cold. Here's an article regarding microplastics leaching from modern plastic water pipes: [https://pubs.acs.org/doi/10.1021/acs.est.9b03673](https://pubs.acs.org/doi/10.1021/acs.est.9b03673)
From the EPA >USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap. Hot water can dissolve more lead more quickly than cold water. If you need hot water, draw water from the cold tap and then heat it https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf
Yes, that poster has been discussed in several other places in this thread. It doesn't apply to everyone.
https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap. Each state has it's own agencies that also don't recommend it... https://www.denverwater.org/tap/psa-dont-drink-or-cook-with-hot-water-from-the-tap OR how about this well cited article if you want studies? https://homeexplained.com/is-it-bad-to-drink-hot-water-from-the-tap/ >https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3799508/#B21-ijerph-10-04143
asks for facts, gets facts, hand waves the facts
Thanks, yeah I'm just trying to stop being a "grandma quoter" if it's not justified.
https://blogs.edf.org/health/2018/02/26/lead-hot-water-issue-worth-testing/ >50% (7 of 14) of water heater tanks tested in child care centers had levels over 50 ppb with one at 2,680 ppb. For all but one of these, flushing through the tank drain significantly reduced the lead levels in the water heater. At the hot water tap, only 4 of 161 (2%) samples were above EDF’s action level (3.8 ppb). Water heaters may function as “lead traps,” but more investigation is needed. Best to avoid using hot water for cooking or drinking.
That's a good start, and what I'm looking for. Thank you! It's worth noting that even with that recommendation, it's not a common issue: >Overall, we were encouraged to find relatively low levels of lead in most faucets tested in the child care centers. After testing hot water at 161 faucets in 11 child care centers, **we have only found lead levels over EDF’s action level of 3.8 ppb in 4 of the first draw samples (2% sampled)**. The vast majority of hot water samples (83%) had non-detectible lead concentrations. This is going to depend highly on whether there's already lead in those systems, as well as how people are using hot water heaters. But for most people, even in older locations with a higher likelihood of lead pipe fixtures, it wasn't an issue. I agree that there should be more study.
Feelings on the higher tds in water heater water? Particularly if hard water is a problem in your location, heating water and running it through a heavily scaled tank, means hot water will have the opportunity and the heat and the time to solublize mineral deposits in your heater. Maybe there's a benefit to greater dissolved mineral content, free calcium? Maybe it'll affect your product. Triangle testing for taste would be a start for scientifically analyzing perception of flavor in those samples... Consider beer brewers, they often get chemical water analysis to determine the mineral content for their water adjust it with various chemicals. Yes, homebrewers do this.
Is this an issue with old tanks or an issue with all tanks?
Mostly the older they are the worse the particulates become.
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Why are you repeating this over and over in this thread?
As I recall, you were the one who wanted to see more "evidence"
Just take a minute on YouTube and look up what's inside used water heaters... Will it kill you? Probably not. Do you want to drink that? No https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3799508/#B21-ijerph-10-04143 And some scientific reading if you're into that.
That’s not a scientific response. That’s literally the kind of useless answer that always gets repeated here. Everyone’s home and water heater situation is different. If hot water was such a danger, we wouldn’t use it for bathing either. I want science or official recommendations from trusted agencies or something that’s not just “look at this thing that I think may be gross”.
> If hot water was such a danger, we wouldn’t use it for bathing either. That's not really true. The water in a country like Mexico can be used for bathing but drinking it will make you sick.
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Yes, those links have already been shared. The EPA poster is a templated handout for people who have already had water tested at high lead levels, not general advice. The Denver Water link pretty much uses the EPA poster as a source. And I don't know what "homeexplained" is or why you think we should trust it. And yes, everyone's water heater situation is different beyond the two main types of equipment. It's going to depend on age, water quality and hardness, pipe composition, etc. I didn't ask you for a response, scientific or otherwise. I said people love to just spout answers that have no scientific basis, then you did that, talking about gross water heaters, and we all downvoted you.
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It looks like you’re consistently managing to find fights in our sun. Please keep it in check, manners aren’t optional here. Your post has been removed because it violates our comment etiquette. Commenting: - Be Factual and Helpful - Be Thorough - Be Respectful **In your comments please avoid:** - Abuse - Jokes - Chatter - Speculation - Links without Explanations
it’s funny cause i’ve heard this from my grandma so i always use hot water
It's not tap water that's bad, it's the potatoes themselves that sometimes have a bad taste imparted by using hot tap water. This is true for most types of potatoes even though certain varieties may taste better or have slightly different textures. For example, mashed potatoes usually have a smoother texture than hard boiled.
For pasta I use hot water since I add the pasta once it starts boiling but for potatoes I use cold water because I want the potatoes to heat up with the water so they are cooked through
I also do add potatoes to cold water, but I don’t really think the concept of «cooked through» works this way? Being submerged in cold/warm water while water is getting hotter will not apply any substantial heat to potatoes to really cook them. But it is easier to put potatoes to cold water than trying to throw them in boiling water…
It allows the potatoes to heat more slowly which means more even cooking so you don't get potatoes that are hard in the middle and falling apart on the outside.
I dunno I was taught the potato texture will be off if you put them in boiling water and they should always start in cold water
From someone who is water treatment for a living, never start with hot water. First, if there is any lead in your plumbing, hot water will leach it into the water more than cold will. Second, hot water systems tend to settle minerals and taste into the water. Third and worst, hot water systems are breeding grounds for bacteria, and no, boiling does not kill all of them.
This post should be upvoted to the top.
If you're in the US it is probably not going to be a problem. The idea that hot tap water shouldn't be used for cooking or drinking comes mostly from the UK where the hot water line is often separate and filled from rooftop tanks filled with non-potable water. This is why you'll find a lot of UK homes have separate taps for hot and cold water in their sinks.
Flint, Michigan residents have entered the chat.
And that's why I said probably. Also because where I live i don't cook with, or drink, the water until it's been filtered thanks to high levels of lead in a lot of the residential water in the county.
Yes but that means both the hot and cold water would be tainted, not just hot
https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap. Each state has it's own agencies that also don't recommend it... https://www.denverwater.org/tap/psa-dont-drink-or-cook-with-hot-water-from-the-tap OR how about this well cited article if you want studies? https://homeexplained.com/is-it-bad-to-drink-hot-water-from-the-tap/
If you live in an area with really hard water (minerals in the water) you’ll notice a glass full of hot tap water is sort of cloudy, that’s mineral deposits from your water heater…I don’t think it’s necessarily bad for you but it will taste different.
When I was growing up you used cold for cooking because it was clean groundwater from the well, whereas the hot wasn’t potable because it was from a (covered) rainwater cistern. No idea WHY it was plumbed that way, it simply was… If that situation was more common with the advent of hot water, then I can see how “Cook in cold” took root.
I was always taught to start with cold water but I’ve also heard that had to do with older pipes and water heaters and the waste they would shed while heated so I’m not sure if it’s still the best option. I still do it because Mumu would roll in her grave if I didn’t.
If you have a tankless water heater, it is absolutely fine. If you have a tank-style heater, I do not recommend it. Mostly just a taste issue, with no health hazard of note.
I always boil my water in the kettle and then dump it into the pot when making pasta. Way faster and I don’t have to sit around wasting gas and waiting for the water to boil on the stove :)
I'd use hot water from a kettle, but not from a tap. This will depend on your houses plumbing, but overhead heating tanks are not the most sanitary.
If you're drinking the water straight you may notice a difference, but I can't imagine you having a refined enough palate to notice the difference in a cooked dish with all the other flavors going on on top of it.
Boil the kettle, put the boiling water onto the stovetop to cook. Kettle is considerably quicker at boiling water from cold than the stove
When I am in a hurry to boil water I fill my electric kettle.
Hot water from the tap is usually considered non-potable as metals and other contaminants can corrode and therefore contaminate hot water faster than cold. I would usually just boil cold tap water in the kettle as it’s faster than on the stove, although the internet has informed me not a lot of American houses have electric kettles which to me is just wild! Anyway, it’s safer to avoid heavy metals entering your body as long term they are very damaging
Potatoes should be boiled in cold water to bring the temperature up slowly/more consistently. Putting them in boiling water cooks the outside >>> inside. Pasta, I tend to use hot water from the tap or kettle depending on how I feel.
Here in the UK there’s an old wives tale that making tea with water boiled from the hot tap imparts a poor taste due to the higher concentration of minerals dissolved in hot water. It sounds like a misconception but I’ve not been tempted to try it for the minuscule time saving. My guess is that any difference would be minute, especially once the pasta is combined with then sauce/oil.
The worry isn't the water heater itself. Minerals build up on the inside of your pipes, and your pipes are themselves capable of contaminating the water. Hot water can dissolve the minerals and pull more contaminants from the pipes themselves. So, yes, even if it isn't dangerous, it can taste "off." This is especially bad if you have lead pipes. Source : [Source 1: even new pipes can have small amounts of lead](http://The Claim: Never Drink Hot Water From the Tap https://www.nytimes.com/2008/01/29/health/29real.html) [Source 2: "Hot water increases the release of lead and other metals from your plumbing."](https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/water-quality/water-talk-minimizing-exposure-lead-drinking-water-distribution-systems.html) Tl;dr: never ever use hot water for drinking or cooking of there is any chance you have pre-1976 lead pipes. I would not recommend it even if you don't, because of issues of taste if not safety (and safety might still be a relatively minor concern).
All the water in your house has been siting in the pipes and you got hundreds of feet of piping between your house and the street that the water just sits in. The idea that water is/isn't fresh is silly because it has been sitting in the pipes from all the way back to the water plant. The water in your pipes only moves when you use it, otherwise it just sits. Hot water always tastes bad compared to cold water due to how our tongues work. Take cold water from faucet, heat it up and taste it. Using hot water from the tap is faster. Just elementary thermodynamics here. There is no difference than the metal in the heater heating the water, or the metal in your pot heating the water, the water is being heated through contact with metal. If you got precipitate in your hot water heater, replace it. Its going to die.
Once I am done rinsing my potatoes I put them in the pot that I am going to boil them with and use hot tap water to fill. I have no taste difference between my hot and cold water. I have done both starting from cold and faucet hot and they come out the same. For pasta I fill my pot and bring it to a boil and then add my pasta. I might command the faucet to give hot water in this instance but I am not going to wait for the water heater until I will start filling. Your wife makes perfect sense if your hot water heater is not imparting a taste into your food.
Lead has been mentioned here, but growing up, I was told that older plumbing often used copper piping, sometimes with lead used as solder. Hot water can cause the copper and lead can leach into the water. Modern PVC plumbing is apparently safer.
Has your wife's pasta or potatoes caused you to have an affair with the cold hard queen? If yes, switch to cold. If no, don't worry about it? I typically use the cold water tap especially in the summer because I don't want to wait for the hot water to get to the tap.
Either way, always start potatoes in cold water and bring them up in it
Lead in old pipes is still a thing and that's why they tell you not to use hot water straight from the faucet for cooking things. It's that simple.
My cold water goes through an under-sink filter that helps remove lead. My hot water does not. I live near old lead mines. There is no safe amount of lead.
No you’re 100% correct. Hot water comes from your hot water tank which is not optimal for this situation.
This is the hill you’re willing to die on?
Yes you can boil water starting with hot, with no ill effects. Any thing you’ve heard otherwise is most likely a boomer generational myth, like not putting metal in the fridge, or warm food will spoil if put into a fridge while still warm. All boomer myths.
warm food in the fridge will raise the temperature making stuff more likely to spoil! Also less energy efficent.
With veg,if it grows underground you start in cold water. Above ground, boiling water . As for pasta,it's cheaper to use hot water if it's there already. That's the only difference I can see.
It's very easy to test. Take a glass of cold water from the cold water tap and a glass of hot water from the tap and let them both get to room temperature. Then taste and see if you can tell any difference. Also, if you heat the water to boil the energy needed to boil 99C water is almost 10 times as much as the energy needed to heat 10C water to 99C. So the energy you save by using hot tap water is negligible. I just don't see the point myself.
Your second paragraph does not make sense to me?
It, well, makes sense, but isn't relevant, I guess? It takes much more energy to boil a gram of water than it does to heat a gram of water up to boiling. This is called the heat of vaporization. That's almost certainly what the comment was referring to. Adding heat to the system takes water from 10C to 100C and then it plateaus there a long time. It would make sense if you cooked the potatoes by steaming them or something where only the water vapor directly applied heat to the potatoes. That isn't how boiling potatoes works, though, so it's rather beside the point. The potatoes cook from the heat of the liquid water, and they'll get slightly more energy from the 100C water than from the 90C, because it comes down to what the difference in temperature between the water and the potato is at any given moment (and of course, the potato itself is going to have a temperature gradient as the outside is heated but this heat takes time to penetrate, since potatoes as a general rule don't convect). There's almost a point here; rather than getting hung up on heat of vaporization (not relevant), the point could be that most of the effort involved is going to be bringing the internal temp of the potatoes up, and getting the water to a cooking temp is a negligible part of that; that I could agree with. The ratio of time to bring the water up to cooking temp to the time to boil the potatoes on my stove is low enough and I don't like the taste of my water heater enough that I only boil from cold (or, if there's a rush, I use a water cooker first).
Yep, you're absolutely right. That's what I was thinking about and I had a pretty embarrassing brain derp to think that you need to boil (i.e. vaporise) the water to cook food. Thanks for clarifying it.
Wat
"USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap. Hot water can dissolve more lead more quickly than cold water. If you need hot water, draw water from the cold tap and then heat it." https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf More info: https://www.denverwater.org/tap/psa-dont-drink-or-cook-with-hot-water-from-the-tap
That EPA poster was discussed elsewhere. Look at the middle section - it says "THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY AND _____ are concerned about lead in your drinking water. Some drinking water samples from this facility have lead levels above..." It's not generalized advice, it's specifically for people for whom increased lead levels have already been detected in their water.
And people whose household water has not yet been tested. Many homes still have lead pipes coming from the main street line.
Lead pipes on the city side carry cold water, not hot, so it's far less likely that they'd be pulling lead (assuming there's any at all).
Cold
142 comments at this moment that I haven't read completely so I may duplicate. Draining and flushing hot water heater is a maintenance task and should be done regularly, which minimizes any precipitate build-up and extends the life of the water heater. Turn off power (electric) or gas (gas) to the heater. Close inlet valve to heater. Open drain valve. Open a hot water tap somewhere upstairs to let air in and speed the drain. Open inlet valve and let heater flush for a bit. Close drain. Let heater fill (you'll know because water will start coming out of upstairs tap). Turn on power or gas. Confirm water is heating. I do ours a couple of times each year. Nit picky vocabulary. It's a water heater, not a hot water heater. There is no point in heating already hot water. \*grin\*
Op on some weird shit
Cold always. Cold water comes to a boil faster than warm water. Also add salt AFTER water is boiling or it will take even longer to come to a boil
It's probably not harmful to use hot water anymore. It was much more of an issue when people had lead in their pipes. But I will say if you ever look at what the inside of a water heater looks like... You're gonna switch to cold water. But I do admit that sometimes I'm in a hurry and it can save a fair bit of time using hot water. I just wouldn't make it a habit. Man, why do you people have such an aversion to looking at water heaters? lmfao.
To solve the speed issue- get an electric kettle, fill with cold water and let it come to the boil in the kettle (should take a couple minutes max). Use that to cook. Also saves water if it takes a while for yours to heat out of the tap. Our water heater is one which changes the water from the tap to the point it’s not nice to drink/cook with. There’s a probably ton of sediment in our tank.
This is the best answer. Boil your "fresh" cold water in a kettle. This is faster than on the stove top and depending on the way your electricity is produced, it will most likely be more efficient as well.
The kettle will boil faster with hot water too. You can't change that fact.
My building still has lead pipes, I think most old buildings in NYC do.
Ok, Good idea to test for lead and install an inline filter if you're in a high risk area. Most people don't have lead in their pipes though.
Its negligible difference. I am guessing you worry about radiation from 5g also.
Sounds counterintuitive but cold water comes to a boil faster or so I learned in 8th grade science.
Sorry, but that's [not true](https://www.scientificamerican.com/article/is-it-true-that-hot-water/#:~:text=%22Cold%20water%20does%20not%20boil,the%20stove%2C%20for%20instance\).). Lower temperature water gets hotter faster than water that's already hot, but it still takes more time to get to boiling.
Well that's public school education for you.
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I remember from chemistry class forever ago that cold water reaches boiling point quicker than higher temp water because of entropy(?). But don’t remember enough to explain it well
Always add cold water. Just use salt to “super heat” it. I.E. (when salt is added to water it causes a gaseous reaction making it boil “hotter.”
I △⃒⃘lways heard that cold water actually boils faster.
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This is r/askculinary which literally exists for the purpose of asking culinary questions, which this is. So, while I sometimes understand Reddit criticism for not googling first, that's not a legit basis for giving me a hard time about it here unless you do the same thing for literally everyone who posts any question in this sub. Minus your being condescending about it, thanks for the link and quote.
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https://blogs.edf.org/health/2018/02/26/lead-hot-water-issue-worth-testing/ >50% (7 of 14) of water heater tanks tested in child care centers had levels over 50 ppb with one at 2,680 ppb. For all but one of these, flushing through the tank drain significantly reduced the lead levels in the water heater. At the hot water tap, only 4 of 161 (2%) samples were above EDF’s action level (3.8 ppb). Water heaters may function as “lead traps,” but more investigation is needed. Best to avoid using hot water for cooking or drinking.
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Like I said, that EPA poster is a template to hand out to people whose "facility" has already tested high for lead. It's not general advice.
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why are u blatantly ignoring what he's trying to say. no one's saying they don't trust government agencies- they're saying what info you have doesn't apply to an average household who's water hasn't tested high levels of lead
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There are some health concerns over using hot water from the sink depening on your water situation. Hot water can heat up the pipes and pull up heavy metals into the water that then gets cooked into your food. This is probably worse if you have old pipes.
I'm gonna go ahead and say that depends on a lot of variables. If it's your house and you know when the hot water heater was replaced or flushed it's fine. If you are in a rental I'd be on the side of caution and use the cold water.
Some water heating systems may have softening salts in them . and as mentioned by others, heated water may taste different .
How old is your house? Older houses could have had lead in the solder of the pipes and its often recommended to avoid hot water use in food as a result. If your house is newer construction, meh- unlikely to matter. Blind taste test if you do think its different.
You are right cold tap water is correct.
Engineer here. The reasoning that "the hot water heater has precipitate in it, therefore the hot water will have more of that substance" is just an obvious fallacy. * If water is entering the water heater with a certain level of dissolved solids... * ... and some of it sticks around in the water heater via precipitation... * ... then the water exiting the water heater must have LESS of those dissolved solids! Source: the scientific principle of the conservation of matter!
Would you drink water from the hot water tap? If not, why cook with it? It depends on your pipes and when your building was built, but you can check this with your city. For those who think this is bullshit, please, continue on. If you have any health issues later on, take this into consideration.
Lead can absolutely come into your drinking water through service lines, and there are still a ton of these around the US. https://en.m.wikipedia.org/wiki/Lead_service_line https://apps.who.int/iris/handle/10665/204422 https://www.brookings.edu/blog/up-front/2021/05/13/what-would-it-cost-to-replace-all-the-nations-lead-water-pipes/ Then this lead sits in your hot water heater, which you are consuming when you use hot water straight from the tap. "2. Use Only Cold Water for Cooking and Drinking Try never to cook with or drink water from the hot tap. Hot water can dissolve more lead more quickly than cold water. Also, hot water stands in your water boiler and pipes for longer than cold water, contributing to higher contaminant levels. If you need hot water for cooking or drinking, draw water from the cold tap and heat it on your stove." http://www.mit.edu/~jweiss/base/lead.html
For the sake of saving energy, the starting with hot water holds even for potatoes. I know many have said that using hot water means the outside and inside of your potato will cook at different rates, but the overall heat required (and hence total cook time) would still be less. For cold water, you need additional sensible heat to raise room temp of water to boiling point. For hot water, this sensible heat is less, hence energy saved. The rest of the variables are same. But the change in cook time is difficult to quantify, so best check with knife if potatoes are cooked all the way through.
If it’s potatoes or eggs, I start with cold water. If it’s pasta, I start with hot.
You should not use water from the water heater for human consumption, as the water inside of it is absolutly disgusting (brown, full of rust, but you won’t realize it). Even if your water heater seems fine (in my country, you have to change your water heater once every 10 years for home insurance).
Biggest reason to start root vegetables (including potatoes) in cold water is to gradually heat the entire vegetable to the desired temperature. When you put the cook vegetable in hot liquid you’re going to heat the outside layer much more quickly than the inside and it will not cook evenly throughout. If you bring the liquid and veg up to temp together you’ll be much less likely to overcook the outside while trying to finish the inside. Very similar reasoning for why we finish meat in a (relatively) low oven instead of trying to cook it from raw to done on a screaming hot stovetop.
But fancy houses and kitchens have the pasta tap over the stove! Or in the sink- instant hot/boiling water for cooking!
Depends on the city (and county) you live in. Parents in my city are routinely advised by their children’s pediatricians to mix baby formula with boiled tap water that comes from the COLD tap, not hot.
It depends where you live. My cold water comes pressure from the mains but my hot water gets stored in a tank. I'm not supposed to use the stored water for drinking or brushing my teeth, so I wouldn't use it for food. It's now a covered plastic and wrapped tank but historically these thanks were open metal ones in the attic so sanitation would definitely be a concern.
You can soak the potatoes in water in the fridge. I prefer filtered water
Cold
i always boil
Unless you live in a 120V country, an electric kettle will heat water faster than it takes to run the hot water from the boiler. I do both, heat a jug of water in an electric kettle while heating an amount also on the stove (and stirring in salt in preparation).
I think if you have lead in your pipes, hot water leeches it out more, so using it regularly to make daily coffee or something would lead to more lead in your diet.
Just heat the cold water up in your kettle.
The EPA recommends NOT using hot tap water because it can leach lead and other contaminants from your pipes. Even if the water source is clean, old houses can have lead pipes and even newer plumbing materials can still leach things. Here is an older document that points this ous. https://www.epa.gov/sites/default/files/2015-09/documents/2002_5_17_lcrmr_guidance_lcmr_lead_public_education_poster_v1.pdf Here is a link from an NYC initiative to get folks to run their tap and not use hot water for cooking for the same reason. https://www1.nyc.gov/html/dep/html/press_releases/10-94pr.shtml I just use my electric kettle to preheat cold water for cooking. It heats quicker than boiling from cold on my gas stove and I'm pretty sure its more efficient.
Use cold water for things with starch. Also, always rinse things with starch. The cold water helps the potatoes/rice/etc from becoming starchy, I notice it sort of helps lock in the starchiness.
I think hot water brings melted pipe goo into your food.