The results of studies on the production of lactic acid from fermented whey are presented in an electrolysis device with minimum electrode spacing. Electrolysis of lactic acid from the fermented, partially deproteinized milk whey is described. The task of this study assumes the production of more concentrated solutions of lactic acid preparations, since further processing of the acid for the purpose of concentrating by traditional methods is energy-intensive and long-lasting [1]. Whey treatment was performed in a diaphragm electrolyzer with a graphite anode and a sealed steel cathode. They are separated by an anion exchange membrane.The distance between the electrodes is minimal and is 30 mm. To ensure the efficiency of the acid accumulation process from the serum, 20% moisture was previously removed [2]. The content of solids in processed raw materials increased to 9%. Strongly fermented condensed whey was supplied to the cathode cell of the cell. Active acidity is about 3.A weak electrolyte solution NaHCO3 enters the anode chamber. The initial whey is distinguished due to its increased acidity by a significant oxidation-reduction potential (over +300). Therefore, the electrolysis process proceeds intensively. With a constant voltage, the initial current strength increases in the first 5-10 minutes of treatment by a factor of 1.5. With appreciable heating, the dependence of the voltage on the current acquires a specific character. Thus, at the twentieth minute of electrolysis, a short-term insignificant voltage drop was observed due to an increase in resistance in the system (cupping the membrane with whey protein substances). The current strength decreases to 0.6 A after an hour of electrical processing. As a result: the pH in the cathode chamber, despite the high current density, remains acidic and weakly acidic throughout the treatment. This means the primary influence of the acidity of the solution being treated on the character of the process of electrolysis for the production of organic acids. The isolated lactic acid is twice more concentrated (by the content of dry substances in solution from 3-4% in studies with less fermented whey to more than 7% in this study). In addition, the cathode chamber retains a fairly high oxidation-reduction potential during the entire treatment, which allows a continuous outflow of the lactic acid produced.