Kvass for homebrewers
Online recipes for bread kvass are either not really appropriate for homebrewers or not nearly genuine kvass.
There are two kinds of on-line recipes (outside of JBK):
- Small 1-gallon batches, with live lactobacillus fermentations meant to be consumed within days. This is the genuine thing, but produces tiny quantities that go off quickly.
- Larger yeast-fermented batches with no lactobacillus fermentation and with much more alcohol than a kvass ought to have, resembling an unhopped ale more than a real kvass.
I'm proposing a recipe for kvass that is low-alcohol, with a batch size that makes brewing it worthwhile, and still involves lactofermentation, but with modern homebrew standards of sanitation and bacteria control. The work starts the night before with preparation and the lactic acid fermentation. The next day you mash and boil.
The method and recipe below is for an 11-litre batch (3 US gallons) at around 2% ABV. That alcohol level is the upper end of the Russian style of kvass. Homebrew sanitation procedures are used to allow keeping the kvass for more than a few days, but the small batch size (compared to typical 19 or 23 litre homebrew batches) means it can still be consumed in a reasonable time, especially as it doesn't get you drunk. This straddles the line between modern home brewing and traditional kvass.
Primary fermentation is carried out in a 19-litre glass carboy (5 US gallons). Following primary fermentation, the kvass is to be siphoned to an 11-litre glass carboy (3 US gallons). This leaves behind most of the sediment, and some more settles in the smaller carboy.
Traditionalist purists may say that the sediment is an important part of kvass, and that the lactofermentation should remain active. This recipe has different goals.
Preparation of the bread
Start with a loaf of rye bread, preferably dark rye bread with caraway seeds. Weight should be 450g to 675g. Toast slices of the bread until dark, almost burnt. No worries if it's slightly burnt. Cut into small cubes, and put into an 150°C (or 300°F) oven on a baking sheet for 30 minutes to completely dry out. The bread will act as a source of starch for the 6-row barley malt enzymes to convert. Browning adds flavour and colour.
Your mash pot should be fitted with a grain bag of natural cloth and very small holes. You can mash on the stove.
A note on the grain and mash: Rye is traditional in kvass, so some of the grain used is crystal rye or caramel rye. The rest should be high in enzymes and husk material, so American 6-row malted barley is perfect. (I'm not unappreciative of the irony of using American malt to make Russian kvass.) Mash temperature is on the high side, which is designed to leave some residual sweetness.
450 to 675 g toasted rye bread, ideally with caraway seeds
454 g (1 lb) crushed 6-row malt
227 g (0.5 lb) crushed crystal rye
45 g (0.1 lb) raisins (optional, but traditional)
Juice of one lemon (optional, if you prefer more sourness)
20 g caraway seeds, if desired, or if the bread had none.
20g white sugar for priming
1.5g pure stevia at priming (optional)
Steps, day 1
Boil 4 litres (1 US gallon) if water, turn off heat. Fit the bag that will hold bread and grain.
Soak the bread (prepared as above) in the water. When temperature drops to around 40°C (104°F), throw in a small handful of grain, and perhaps a small spoonful of live culture yogurt and a teaspoon of sugar. This will start a lactobacillus fermentation.
Leave this overnight, covered. Insulate with a towel.
Steps, day 2
The next day, raise the liquid to mash temperature, add the rest of the grain to the grain bag and mash it with the bread at 68°C (155°F) for 60 minutes, stirring occasionally.
Sparge, collecting 12 to 13 litres. (Or just dunk the grain bag into another pot holding 8 litres of 70°C water, and mix the two volumes of water.) You'll have more than the final 11 litres, but overage will be left behind with sediment when you siphon.
To the wort, add the raisins and lemon juice and boil it all for 10 to 15 minutes. Mashing and boiling kill lactobacillus that developed overnight; lactic acid sourness remains. No need to boil longer since there are no hops. Don't worry about pectin. Real kvass is naturally cloudy anyway.
Cool to fermenting temperature and pour into the fermenting vessel through a funnel, including raisins and caraway seeds if possible.
Ferment with ale yeast, ideally from a previous batch of beer until fermentation stops (3 days, probably). (Some use bread yeast, but really ... we're homebrewers, not 19th century Russian peasants.)
Settling and bottling
After primary fermentation is complete siphon to an 11 litre glass carboy, to settle, for a week to ten days.
Prime the batch with 20g white sugar and 1.5 g pure stevia, lightly boiled. Bottle in half litre bottles.
I imagine someone will say "seems like a lot of trouble for 2%". My answer: my wife really likes it.