I enjoy the flavor of kvass - a Russian / eastern European malt flavored soda - but it's hard to find where I live. The process involves really aggressively toasting some rye bread, boiling it with eaisans and sugar, straining it, and then brewing it with ordinary baking yeast in 2-liter bottles until it reaches your desired carbonation level. The end result is really refreshing.
If you can get it where you are, have you considered trying malta[0][1]?
[0] https://en.wikipedia.org/wiki/Malta_(soft_drink)
[1] https://www.findmeabrewery.com/blog/malta/
I have tried malta, and I like it. But it's a bit sweeter. I think it's a worthwhile substitute if you don't want the fun of trying to make something that might go wrong.
Me too except I just use rye malt instead of the bread and without making any dough with it. The malt is cheap and easy to get in UK thanks to home brewing suppliers whereas rye bread is super expensive.
My only challenge is controlling the gassiness - it’s so vigorous that the moment I even slightly open the cap the whole thing fizzes up like crazy - opening it normally would result in a kvass fountain shooting up like 30cm. :)
How does this not become alcoholic?
Short brewing time. Finnish sima is similar - sugar, lemon, water, yeast, ferment for a couple of days. Alcoholic drinks are usually fermented much longer, aged, and processed much more intensively.
It is usually alcoholic. 0.5-2%. Here stores sell most commonly 0.5% one which is regulated to be sold like a non-alcoholic drink.
I understand that Kvass is around 1% alcohol.
By Russian standards, this is "non-alcoholic".
I once got a Root Beer brewing kit as a gift. It noted that a trivial amount of alcohol would be produced by the process (no included or added yeast either!) and it wasn't a big deal.
Usually they remove the alcohol later. The taste is similar to a alcohol-free Guinness (but sweeter).