Ryazhenka

Origin and etymology

Russian and Soviet sources call it "Little Russian" or "Ukrainian ryazhenka" or "Ukrainian soured milk" (украинская простокваша, ukrainskaya prostokvasha) and attribute its origin to Ukrainian cuisine. The name is cognate with the Ukrainian "пряжений" as in "пряжене молоко" (pryazhene moloko, "baked milk").

Similar traditional products made by fermenting baked milk have been known in Russia as varenets. While some dictionaries define both names as synonyms, the industry standard GOST distinguishes between the two products, specifying somewhat different production processes.

Similar products are also qatiq and kaymak in Turkic countries. Before fermentation, milk should be heated to a high temperature. This is the main difference of ryazhenka, qatiq and kaymak from other yoghurt drinks.

Production

Ryazhenka is made by pasteurising milk and then simmering it on low heat for eight hours or longer. Historically, this was done by placing a clay pot (glechik or krinka) with milk in the traditional Russian oven for a day until it is coated with a brown crust. Prolonged exposure to heat causes the Maillard reaction between the milk's amino acids and sugars, resulting in the formation of melanoidin compounds that give it a creamy color and caramel flavor. A great deal of moisture evaporates, resulting in a change of consistency. In household production, sour cream (smetana) is subsequently added to trigger fermentation. In modern industrial production, pure thermophile bacterial cultures (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) are used instead. The mixture is then kept in a warm place. The fermentation occurs at temperatures above ca. 40 °C / 100 °F and usually takes from three to six hours.

The fat content of industrially produced ryazhenka is typically 3.5−4%, but in general it is allowed to vary from