1/2loaf of Rye Bread, cut into 1" squares and toasted
Pour Warm Water into an extra large bowl or bucket.
Add 10 Tbsp of Kvas concentrate and 1 3/4 cups of Sugar, stir until dissolved.
Add 1/2 Tbsp of dry yeast and stir until it dissolves.
Add 10 + Raisins
Add Chopped toasted bread
Cover with a breathable cotton cloth. Secure cloth with a rubber band or string.
Let Kvas sit in a warm place (about 85 °F) to ferment for 18-20 hours.
After 18-20 hours, remove raisins and bread from Kvas.
Strain kvas through multiple layers of a cheese cloth and pour into juice bottles that can be sealed tightly.
Fill juice bottles 3/4 full to allow room to expand. While Kvas is still warm, you want to put the lids on loosely. Once it cools in the refrigerator, tighten the lid.
Most of the store bough kvas, that I tried, did not taste that great. Boise has 2 Russian/European Stores where you can find the Kvas Concentrate. I go to the one on Fairview, called Irina's. It's across from Idaho Athletic Club near Locust Grove. There's also one next to China Grand Buffet on Fairview, near Five-Mile. Most Russian stores also sell a great Rye bread; just ask them what kind you need for kvas. Supposedly the Rye Bread is found at Winco too, I will have to look into that.