Kvass

Kvass is a traditional eastern European beverage that was originally made from fermenting stale bread. According to this article: “It is also recognized that kvass is safer to drink than water. Tolstoy describes how Russian soldiers took a ladle full of kvass before venturing from their barracks onto the Moscow streets during a cholera epidemic. Because kvass protects against infectious disease, there is no worry about sharing the glass.” Although it is fermented, this slightly sweet beverage is considered nonalcoholic (0.05% to 1%). It can be made with the addition of fruits like strawberries and raisins or herbs like mint. A distinction is made between bread kvas and beet kvas. Not only is kvas popular in Russia, Ukraine and Poland, it is enjoyed in Belarus (kvas), Latvia (kvass), Lithuania (gira), former Soviet states like Georgia, Kazakhstan and Armenia, and is even known in China (géwǎsī/kèwǎsī)

• Bread Kvass is an Eastern European fermented beverage typically made with black or other rye bread and is imbibed as a thirst quencher in the summer or as a health elixir. It is also used as a cooking ingredient for soups like Russian botvinia and some versions of okroshka (some recipes call for buttermilk in place of the kvas as a souring agent), and Polish żurek.
• Beet Kvass is a traditional probiotic tonic popular in Eastern Europe and Russia. Beet kvas is also used in Polish Christmas Eve Beet Soup. It has a complex flavor profile that is not often found in beverages in the modern American diet—sour, salty, earthy, sweet, umami and sometimes fizzy. Like its relative kombucha, it is an acquired taste, but this nutrient-rich, naturally stimulating beverage is wonderful for digestive health and beneficial to those with chronic diseases.
  

See also :

• fermented food
• Probiotics
• kombucha
• Beets

Benefits and uses of Kvass are

Folk medicine values beets and beet kvass for their liver cleansing properties and beet kvass is widely used in cancer therapy in Europe. Anecdotal reports indicate that beet kvass is an excellent therapy for chronic fatigue, chemical sensitivities, allergies and digestive problems.