Ryazhenka - a fermented milk drink produced from cow's Baked milk (Russian:топлёное молоко, Ukrainian: пряжене молоко, Belarusian: адтопленае малако) is a variety of boiled milk that has been particularly popular in Russia, Ukraine and Belarus. 

It is made by simmering milk on low heat for eight hours or longer/, fermented lactic streptococcus cultures. Compared with yogurt it has a delicate flavour fermented drink, especially loved children, its taste is sweet and gentle than the yogurt, and the thick consistency Lactic acid stimulates appetite, improves the digestive tract and kidneys. Besides ryazhenka perfectly quenches thirst, so that is what it along with the water it makes sense to drink in hot weather.  Ryazhenka has different dietary and medicinal properties. In particular protein from fermented  milk is absorbed much faster than from milk. Ryazhenka restores balance in the stomach, so it's good to drink after taking a lot of junk food. In addition, it contains a complex of biologically active substances (enzymes, free amino acids, antibiotic substances), accumulating as a result of lactic acid bacteria. Ryazhenka is very useful in diseases of the liver and biliary tract, obesity, atherosclerosis, and hypertension. In one glass of sour milk contains a quarter of the daily requirement for calcium and 20 percent daily requirement of phosphorus.