Centrifuges in Brewing
MBAA TQ doi:10.1094/TQ-48-2-0419-01 |
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Paul H. Chlup and Graham G.
Stewart. The International Centre for Brewing and Distilling,
Heriot-Watt University, Edinburgh, EH14 4AS, Scotland.
Abstract
Centrifuges have a number of applications during
the brewing process in order to increase brewery throughput as they
decrease clarification times and improve tank use efficiency. However,
the cropping of yeast with a centrifuge at the end of primary fermentation
is its principal function. This article focuses on the effect of a disc
stack centrifuge on yeast and beer physical stability. An ale yeast
strain was subjected to different operating conditions during
centrifugation. Yeast viability decreased due to processing conditions
during yeast cropping with a centrifuge. A relationship has been
established that mannan, an unfilterable haze constituent, as a function
of G-force and centrifugation cycle, was released from the yeast cell
wall whilst beer haze increased. Furthermore, yeast intracellular
glycogen and trehalose levels were depleted.
Keywords: beer stability, brewing,
centrifugation, fermentation, flow cytometer, wort, yeast
S�ntesis
Las centr�fugas tienen numerosas
aplicaciones en la cervecer�a, aumentando la productividad mediante la
reducci�n del tiempo de clarificaci�n y aumentando la eficiencia del uso
de los tanques. Su uso principal es la recuperaci�n de levadura al
finalizar la fermentaci�n primaria. Aqu� se discute el efecto de una
centr�fuga de discos apilados sobre la levadura y sobre la estabilidad
f�sica de la cerveza. Se centrifug� una levadura de fermentaci�n alta bajo
diferentes condiciones operativas. La viabilidad de la levadura disminuy�
como consecuencia de la recuperaci�n mediante centr�fuga. Se pudo
establecer que manano, un constituyente de la turbidez no filtrable, fue
expulsado de la pared celular de la levadura en proporci�n a la fuerza g
ejercida y el tiempo de centrifugaci�n, aumentando as� la turbidez de la
cerveza. Tambi�n se observ� una reducci�n en la levadura de los niveles de
trehalosa y de glic�geno intracelular.
Palabras claves: Centrifugaci�n, cit�metro de
flujo, estabilidad de cerveza, fermentaci�n, levadura, mosto, proceso
cervecero
