Dairy horse breeding in Ukraine is not a major source of milk and dairy products, although its nutritional and therapeutic effects on the human body have been known since ancient times. The main product made from mare’s milk is koumiss - an alcoholic-lactic drink, which, due to its chemical composition, has a positive effect on the human body. The technological process of preparing koumiss consists in mixing a working starter with freshly milked mare’s milk, which requires a fairly clear dosage of these components by acidity and temperature, with subsequent mixing, cooling and corking of the finished mixture, therefore the purpose of this work was to test existing methods for calculating the mixed components by acidity using the technological square method and develop new ones using the Pearson square method. It has been established that when using the technological square method, the initial data are arranged horizontally and, when calculating the difference in acidity between milk and starter, taking into account the planned acidity of the mixture, the smaller value is subtracted from the larger value, and the calculations are carried out in different directions, as a result, a proportion appears, divided by a vertical line, when calculating which we will obtain the amount of starter of a certain acidity that should be added to the mare’s milk. Using this method, and considering the results obtained in general form, we obtained both a formula for determining the required amount of starter culture that must be added to a certain amount of milk, depending on their acidity, to obtain a mixture of the planned acidity, and an explanation of the existing formula for determining the temperature to which milk should be heated, and also derived formulas for calculating the ratio of the amount of milk and starter culture, depending on their initial acidity and temperature, to the planned acidity and temperature of the mixture in the production of koumiss to simplify calculations. Verification of the derived formulas confirmed their workability; therefore, they can be proposed and recommended for use in farms not only for koumiss production but also at dairy industry enterprises.

Keywords: starter culture, mare’s milk, koumiss, acidity, temperature, Pearson’s square.