Katyk is a traditional fermented milk product associated with the Volga–Ural region. This study describes the laboratory-scale development and characterization of Katyk produced using the reservoir method. A 2.0 kg batch of cow’s milk was standardized to a target fat content of 2.5%, heat-treated at 92 °C for 5 min, cooled to 40 °C, inoculated with a thermophilic direct-vat-set (DVS) starter culture, and fermented at 40 °C to a target pH of 4.6. The reported fermentation time was 4.5 ± 0.3 h. The final product had a reported titratable acidity of 92.0 ± 3.0 °T, protein content of 3.12 ± 0.08%, and syneresis of 4.2 ± 0.5%. The material balance indicated 1.815 kg of finished product, corresponding to a yield of 90.7%, compared with a theoretical estimate of 1.852 kg (92.6%). During refrigerated storage at 4 °C for 7 days, lactic acid bacteria counts were reported to remain above 10⁷ CFU/g, while coliforms and Staphylococcus aureus were not detected under the reported test conditions. Sensory evaluation by a 10-member panel produced reported scores of 4.4/5 for taste and 4.3/5 for overall acceptability. The findings provide a laboratory-scale process description and preliminary quality profile for reservoir-method Katyk production, establishing a basis for further process optimization and scale-up.