The Impact of Production Technology on the Quality of Potato Spirit

Spirit drink, known in Central and Eastern Europe as 'okowita' (its official designation is 'spirit'), is obtained by distilling fermented plant raw materials. Unlike vodka, which is produced from highly purified ethyl alcohol of agricultural origin, 'okowita' is characterised by the preservation of the natural aromatic and flavour compounds originating from the raw material and produced during the process of alcoholic fermentation. The study aimed to assess the impact of production technology on the quality of potato spirits. The effects of the methods used for the pretreatment of raw material, starch hydrolysis and fermentation, and yeast strains were examined in relation to the fermentation efficiency and the chemical composition of the distillates. The yeast strains were the key factor determining fermentation efficiency. The SafSpirit and Pinnacle yeast strains provided the highest fermentation yields (85.0-97.7% of the theoretical), while the Ethanol Red strain provided the lowest yield (<83%). No advantage of separate hydrolysis and fermentation (SHF) over simultaneous saccharification and fermentation (SSF) was observed. A characteristic feature of potato distillates was their high isobutyl alcohol content, ranging from 557 to 1437 mg/L of 100% v/v alcohol, i.e., more than twice that of 3-methyl-1-butanol. Methanol concentrations remained below the limit specified in EU Regulation 2024/1143 (≤1000 g/hL of 100% v/v alcohol). The results are promising in terms of the potential for the production of craft potato spirit drinks.