Kinetics of the changes in concentration of acetals and esters during three-days of alcoholic fermentation of starchy products carried out according to the method of pressureless liberation of starch (PSL) has been presented. It was found that formation of acetals was diversified depending on the kind of raw material. Total concentration of esters in distillates was conditional mainly upon the presence of ethyl and methyl esters of acetic acid. It was found that esters of higher alcohols were produced, first of all, during the main fermentation. The relation between higher acidity and high concentration of acetal forms of acetaldehyde and acro-lein was observed in raw spirits originating from agricultural distilleries. (c) 2005 Elsevier Ltd. All rights reserved.