Fermented Milk Products from All Over the World • Ryazhenka (Russia, Ukraine, Belarus)
Have you ever tasted cooked milk? Well, this is what ryazhenka is. The milk is cultured and then baked, the result being a fermented drink based on milk, which has an ivory color and a flavor that almost tastes like caramel. Practically, the milk is placed in the over, at low heat, and allowed to simmer slowly for 6 to 8 hours. During this time, due to the heat, the water in the milk evaporates, creating a slightly thicker and creamier consistency, while the sugar and amino acids in the milk react, giving it its sweetish taste and light color. Before putting the milk in the oven, you need to culture it. Sour cream, buttermilk, or kefir can be used for the culturing of the milk. But, do have in mind that what you will choose to use as a starter culture will give its properties to the final product. Thus, if you use sour cream, for example, the ryazhenka will be creamier and sweeter, but if you use kefir, then expect a sour product with a grainy texture.
Lactobacillus delbrueckii subsp. bulgaricus is the type of bacterium responsible for turning milk into ryazhenka. This bacteria loves heat, so it is a thermophilic species, meaning that it will do best at temperatures of 40 degrees Celsius or 100 degrees Fahrenheit. It is also an anaerobic bacteria, meaning that it loves environments without oxygen. So, in order to obtain ryazhenka, you will need to ensure this temperature to your cultured milk.
To prepare ryazhenka, use whole milk that is fresh, with no signs of souring. You can use it raw or you can pasteurize it, so yes, you can use store-bought milk as well, as long as it is whole milk. You will also need sour cream or kefir, according to preferences. For every 2 cups of milk you use, you will need 1 tablespoon of sour cream or kefir. You can use a slow cooker for the cooking process of the milk, just make sure to let the lid slightly open, so that water can evaporate from the milk. Use a low temperature and allow the milk to cook for 8 to 10 hours. Your ryazhenka is ready when a golden crust formed on top of the milk. You can also turn the slow cooker on high and cook the milk for 4 to 5 hours only, but it is better if you can slow cook it on low.
You can also put the pot with cultured milk in the oven, on the middle rack, and turn the heat in the oven at 225 degrees Fahrenheit. Again, you will have to cook it for 6 to 8 hours, until you see the golden crust formed on the top. To enjoy it, just remove the crust.