Pilot-Scale Studies on Extended Aeration at Fermentor Fill. Katherine Mauel Pearlstein, Technical Center, Anheuser-Busch, Inc., St. Louis, MO 63118-1852. J. Am. Soc. Brew. Chem. 46:0108, 1988.

This study examined the effects of oxygen supplementation on fermentation performance. Two types of fermentations were performed in 6-gal. pilot-scale fermentors: 1) wort was aerated to saturation and pitched; 2) wort was aerated to saturation, pitched, and given additional air for 6 hr. The fermentations were monitored through primary and secondary stages. Several parameters were examined: yeast count, extract, alcohol concentration, degree of fermentation, and pH. The fermentations with extended aeration were somewhat more vigorous during primary fermentation and had a lower pH. By the end of secondary fermentation, the differences observed were reduced; however, the pH remained substantially lower with extended aeration. Pyruvic acid in the finished beer was considerably higher under extended aeration, whereas sulfur dioxide and acetaldehyde were lower. Flavor evaluation showed preference for the extended aeration treatment.

Keywords: High-capacity fermentors, Aeration, Fermentation