Recipe 1: Dilute the kvass concentrate with warm water in a volume ratio of 1:10, that is, take 5 liters of water per 0,5 l of the kvass concentrate. Add 3 grams of yeast to the mixture and keep in warm place for 10 to 12 hours. Cool the kvass, carefully pour into another container to remove the sediment, and it is ready to use.
Recipe 2: Dissolve 4 teaspoons of kvass concentrate in one glass of carbonated water.
If you want sweeter kvass, instead of 5L use 3L of water, and add more teaspoons of kvass concentrate to sparkling water.