The Effect of Wort Aeration using a High Oxygen Concentration on Fermentation, Yeast Physiology and the Quality of the Finished Beer

By Nobuyoshi Sasaki, Y. Yasuda, T. Imai, T. Takeuchi and M. Ohkochi Kirin Brewery Co., Ltd., Yokohama, Japan. This poster was originally presented at the MBAA 112th Anniversary Convention, Keystone, Colorado, 1999.

Abstract
Wort aeration using a high oxygen concentration is an effective method of maintaining a high concentration of dissolved oxygen using a small quantity of gas. However, it is known that yeast cells produce active oxygen in the presence of a high oxygen concentra- tion, which results in the cells being stressed by oxidation. When brewing yeast is subjected to a high oxygen concentration, the result- ing oxidation stress causes flavor abnormalities in the fermenting and finished beer. Therefore, we carried out a detailed study using gases of various oxygen concentrations. In addition to analyzing the flavor of the fin- ished beer, we analyzed the physiology of the yeast cells. Here, we discuss the advantages and disadvantages of high oxygen aeration from the standpoint of flavor and yeast physiology.
Keywords: Wort Aeration, Yeast Physiology, yeast Vitality, Wort Oxygenation, Wort Aeration Using Pure Oxygen  

Sintesis
La aeration del lupulo usando altas concentraciones de oxigeno es un metodo efectivo para mantener una alta concentration de oxigeno disuelto usando una pequena cantidad de gas. Sin embargo, se sabe que las celulas de levadura producen oxigeno active en Ia presencia de altas concentraciones de oxigeno, lo que resulta que las celulas son estresadas par la oxidation. Cuando la levadura para la elaboracion de la cerveza se somete a altas concentraciones de uxigeno, el estres de oxidacibn que resulta causa anormalidades de sabor en la cerveza fermentada y terminada. Por eso, elaboramos un estudio detallado usando gases con varias concentraciones de oxigeno. Ademas del analisis de sabor de la cerveza terrninada, nosotros analizamos la fisiologia de las celulas de levadura. Aqui, nosotros discutimos las ventajas y desventajas de la aeracidn de alto oxigeno desde el punto de vista de la fisiologia del sabor y de la levadura.