Yeast Management - The Balance Between Fermentation Efficiency and Beer Quality
MBAA TQ vol. 38, Number 1, 2001, Pages 47-53 |
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Graham G. Stewart. The International Center for Brewing and Distilling, Heriot-Watt University, Riccarton, Edinburgh, Scotland, UK. Some parts of this paper were presented at the World Brewing Congress 2000, Orlando, Florida, USA and other parts presented at the 1998 Twenty Fifth Convention of the Institute of Brewer�s Asia Pacific Convention, held in Perth, Australia.
Abstract
Many contemporary brewing procedures require that increasing care must be devoted to yeast handling and management procedures. This study considers three such procedures: Fermentation
performance of ale and lager yeast strains in 15� and 20� Plato wort. The results indicate that the lager strain exhibited superior performance to the ale strain after repeated pitching, especially in the very high
gravity wort. Effects of high gravity brewing and acid washing on the
condition of brewer's yeast. Provided all the accepted protocols for acid washing of yeast are obeyed, yeast harvested from very high gravity fermentations
(20� P) can be effectively acid washed. Fermentation performance and beer quality employing centrifuged yeast. Failure to control the centrifuge temperature will have negative effects on the quality and stability of both yeast and beer.
Keywords: yeast, fermentation, high gravity brewing, beer stability, glycogen, trehalose
S�ntesis
Muchos procesos de la elaboraci�n de la cerveza contempor�neos requieren que se dediquen mayores cuidados al manejo de la
levadura y de los procesos de manejo. Este estudio trata tres de esos
procesos: El rendimiento de la fermentaci�n de cepas de levaduras tipo ale y lager en mosto plato a
15� y 20�. Los resultados mostraron que la cepa lager tuvo un rendimiento superior a la cepa ale despu�s de varios procesos, especialmente en el mosto de muy alta gravedad. Los efectos de la elaboraci�n de cerveza de alta gravedad y el
lavado �cido en la condici�n de la levadura. Con la condici�n de que se sigan todos los protocolos aceptados para el lavado �cido de la levadura, la levadura que se cosecha de fermentaciones de alta gravedad (20� ) puede ser lavada en �cido efectivamente. El rendimiento de la fermentaci�n y la calidad de la cerveza usando levadura centrifugada. El no controlar la temperatura de
centrifugado tendr� efectos negativos en la calidad y estabilidad de la cerveza y la levadura.
