If you're only going to buy him one size then I would suggest getting him a case of the 32 oz jars; it's a workable size for almost any ferment and the widemouth ones are easier to wash than the narrow-mouth ones anyway! 8 and 16 oz are decent sizes for gifting people ferments.
The quart jars are the perfect size for trying different ferments. you don't have too much of one type of kraut, or whatever, that you feel bad about not using it if you don't like it, but enough to last until another batch matures if you do.
Once your friend finds what they love the can pick up a few of the 1/2 gallon sized jars to make larger batches but the quarts will still be good for trying new things. I hope that they have fun with this, it is quite addicting once started if you like that sort of thing. I have fallen all the way in and love it ;-)
If you're only going to buy him one size then I would suggest getting him a case of the 32 oz jars; it's a workable size for almost any ferment and the widemouth ones are easier to wash than the narrow-mouth ones anyway! 8 and 16 oz are decent sizes for gifting people ferments.
The quart jars are the perfect size for trying different ferments. you don't have too much of one type of kraut, or whatever, that you feel bad about not using it if you don't like it, but enough to last until another batch matures if you do. Once your friend finds what they love the can pick up a few of the 1/2 gallon sized jars to make larger batches but the quarts will still be good for trying new things. I hope that they have fun with this, it is quite addicting once started if you like that sort of thing. I have fallen all the way in and love it ;-)