Yield will be about a gallon. Let stand 10-12 hours. If not chilled at once it will continue to ferment and shatter the bottle if it cannot blow its cork. Let stand for 3 to 4 hours. For drink the peasant diet had kvass, which was much like the 'small beer' of Western Europe.
Homemade kvass is somewhat effervescent and only slightly alcoholic.
It has never enchanted many non-Russians, but it had an important place in the peasant diet. Preheat the oven to 200F. Place the bread in the oven for about 1 hour, or until it is thoroughly dry. With a heavy knife, cut and chop it coarsely. Bring 6 quarts of water to a boil in an 8-quart casserole and drop in the bread. Remove from heat, cover loosely with a kitchen towel, and set it aside for at least 8 hours.