For the preparation of a healthy and refreshing bread kvass, Kusher Rye Unleavened Bread is a necessary ingredient. You might ask, why Kusher bread? Our answer: the fermentation of our bread exclusively uses lactic acid bacteria instead of factory-made yeast. Using this bread results in a kvass that is fresh and crisp. In addition, you may be assured that with this bread, you will get no preservatives, dyes, taste stabilizers, or shortening, which are common ingredients in many breads made by other manufacturers.
Chop the bread into small pieces and toast on low heat in the oven. For the first portion of the kvass, use a large loaf of bread. Fill a three-liter glass jar halfway with bread cubes. Boil water and add sugar (about 10-15 tablespoons), cool down, then add to the jar. For a more intense taste, add a handful of raisins.
Cover the jar with cheesecloth and leave to ferment in a dark place (NOT in the fridge!). In a day or two, the fermentation will begin. The bread cubes in the jar will begin to move up and down, increasing the intensity of the flavor with each day. This first part of bread kvass will be ready in 3-4 days.
Pour the ready kvass from the jar. Throw away about half of the bread cubes, leaving the rest in the jar. Add water, a handful of freshly dried bread cubes, 2-4 tablespoons of sugar, a few raisins, and cover with cheesecloth for fermentation. If you make this new portion of kvass in the evening, it will usually be ready by morning. Repeat this process until you have your desired amount of kvass.
A lot of sugar goes into the first portion of kvass. This is needed to begin the fermentation process, and so the brew does not go sour. If you decide not to use raisins, just add more sugar. With each additional step, add sugar to taste, or about 3-4 tablespoons.
For the kvass, you must use a container that will not oxidize. If you use a pot, it is best to use an enamel one.
Add sugar to taste. If you like your kvass more sour, use less sugar. Use more sugar in the first portion of the kvass.
The color of the kvass depends not only on the type of bread, but also to which degree it is toasted. However, it isn’t worth over-toasting or burning the bread. The burnt taste will be felt in the final product.
The intensity and length of the fermentation process depends on the temperature of the room. A higher temperature will speed up the process. You must take this into account, and keep an eye on the kvass so it doesn't over-sour.
Raisins not only help with the fermentation process, they also imbue the kvass with carbon dioxide, giving it some bubbles and carbonation.
If you don’t want to make a large amount of kvass all at once, then put the soaked bread cubes into a jar and place into the fridge. Before making another portion, take the jar out of the fridge and bring to room temperature. Add sugar, and you are ready to make more kvass!