Ryazhenka (ryazhenka, Ukrainian ryazhanka) is a fermented milk made from baked milk – milk held just below boiling for hours until it turns a light caramel-tan and grows a browned skin. The baked milk (toplyonoye moloko) is cooled, cultured and set warm, like yogurt, into a thick, mildly sour drink with a toffee-like flavour. It’s widely sold in Eastern Europe and in Eastern European shops abroad, and it’s easy to make at home with a low oven or slow cooker.
What Ferments It
A study of traditional fermented milks from across Russia sequenced three home-made ryazhenkas from the Stavropol, Tula and Primorsky regions. Streptococcus made up 61–98% of their bacteria, with Lactobacillus (up to 39% in one sample) and small amounts of Leuconostoc and Lactococcus, and the samples had a pH of 4.5–5 (Kochetkova et al., 2022). The pattern was general: products made from baked or pasteurized milk and fermented warm (ryazhenka, cottage cheese and matsoni-like milks) were dominated by Streptococcus, while raw-milk products soured at room temperature were dominated by lactobacilli or lactococci. That’s why ryazhenka is cultured with yogurt-type thermophilic bacteria such as Streptococcus thermophilus, at yogurt temperatures.
Where the Caramel Comes From
Long heating sets off browning reactions between milk sugar and protein, and they produce caramel-smelling compounds. Flavour chemists identified dihydromaltol in ryazhenka, alongside furaneol (DMHF), which had the strongest effect on its caramel flavour (Preininger et al., 2009). The heat also changes the milk proteins, which helps give ryazhenka a thick, smooth set. The longer and darker the bake, the stronger the toffee notes.
Live Cultures
The baking happens before fermentation, so homemade ryazhenka contains live bacteria, like yogurt. Products heat-treated after fermentation don’t; check the label for “live cultures”. As with any fermented milk, that makes it a fermented food rather than a probiotic, which requires specific strains with shown benefits (Marco et al., 2021).
Ryazhenka, Varenets and Kefir
Varenets is a close relative, also made from baked or long-heated milk and cultured warm. Kefir is quite different: it’s fermented at room temperature by kefir grains, a mix of bacteria and yeasts that makes it fizzy and slightly alcoholic. If you know yogurt, ryazhenka is the easier step: the method is our yogurt method with baked milk. For more Eastern European and Caucasian fermented milks, see matsoni and kefir vs yogurt.