Kvass

KVASS, a Russian folk beverage obtained from floury and sugary food substances through lactic acid and alcoholic fermentation. Depending on the starting materials, one distinguishes between "bread," "fruit," "berry," and other types of kvass. For the preparation of bread kvass, flour, bread, malt, or mixtures thereof are used; for flavor improvement, sugar, mint, molasses, and honey are utilized. There are many methods for preparing bread kvass; their essence boils down to the saccharification of the starch of the starting materials by means of malt diastase, the preparation of wort, and its fermentation with yeast. The following varieties of bread kvass are known: "Russian kvass," prepared from rye flour and rye malt; "Bavarian kvass," from red barley malt, wheat flour, and molasses; "sour shchi," from rye and barley malt and wheat flour; and "white sugar kvass," from rye rusks, wheat malt, and sugar. Fruit and berry kvasses (pear, cranberry, lemon, raspberry) are either ordinary bread kvasses flavored with juice or syrup from fruits and berries, or they are prepared directly from fruits or berries with the addition of sugar and yeast. "Dry kvass" refers to dried, malted material for bread kvass, to which sugar and yeast must be added when making the beverage. The composition of kvass fluctuates very widely even within the same variety. The main components of bread kvass are as follows: lactic acid (0.21–0.40%), acetic acid (0.015–0.045%), carbon dioxide (0.01–0.35%), alcohol (0.05–1.20%), sugar (0.48–7.36%), proteins (0.15–0.21%), and dextrin (0.07–1.16%). Kvass is used as a thirst-quenching, flavorful, refreshing beverage; its nutritional value is insignificant. Kvass, especially in many localities of the USSR, can play a role in the fight against alcoholism by replacing beer and other alcoholic beverages. Sanitary supervision over the preparation and sale of kvass aims to combat poor quality and the adulteration of kvass. Kvass can acquire properties harmful to health due to the poor quality of the starting materials (spoiled flour and rusks, contaminated water), unhygienic preparation (dirty bottles, old non-disinfected corks), and poor storage. In the latter case, in addition to an excessive amount of lactic and acetic acids, butyric and formic acids may also form in it; such kvass is capable of causing gastrointestinal disorders. Kvass from artisanal production, which is not under sanitary control, should generally be considered suspicious from a sanitary standpoint. Among the adulterations of kvass, the addition of saccharin is most frequently encountered, which aims not only to replace sugar but partly to impart stability to the beverage. Berry kvasses are sometimes colored with coal-tar dyes. (Regarding saccharin and dyes in beverages, see Fruit Waters.) The scheme for the sanitary examination of kvass includes the determination of specific gravity, total acidity, volatile acids, carbon dioxide, alcohol, sugar, saccharin, heavy metal salts, and coloring.