Fig. (2) General scheme of sorghum diluted syrup fermentation (all experiments were performed in triplicate): 1 – a flask at atmospheric pressure; 2 – a flask at atmospheric pressure with repeated (10 min) connection to a vacuum system for boiling the medium and maintaining boiling (20±5 mmHg); 3 – a flask at constant reduced pressure without boiling (80±5 mmHg); 4 – Liebig condenser; 5 – tee; 6 – vacuum meter; 7 – water jet pump; 8 – thermometer; 9 – hydraulic seal; 10 – allonge for collecting fractions under vacuum; 11 – receiving flask; 12 – reservoir with ice; 13 – Vyurtz nozzle; 14 – heated magnetic stirrer.