Olive Oil Addition to Yeast as an Alternative to Wort Aeration
MBAA TQ vol. 45, no. 1, 2008, pp.
17-23 |
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Grady Hull. New Belgium Brewing Company, Fort Collins, CO.
Abstract
To extend the flavor stability of their beers, many breweries are researching
ways of reducing oxygen ingress throughout the brewing process. However, the
practice of aerating the wort prior to fermentation is almost universal in the
brewing industry, because oxygen is necessary for yeast health and growth.
Recent studies have shown that alternative methods to traditional wort aeration,
such as aeration of the yeast prior to pitching or the addition of the
unsaturated fatty acid linoleic acid, can yield fermentation characteristics
similar to wort aeration. It has also been shown that using these alternative
methods instead of aerating the wort can reduce oxidation potential. This paper
reports the findings of a series of full-scale production tests that were
conducted in an operating brewery to evaluate the effects of an alternative
yeast treatment. By mixing olive oil into the yeast during storage, instead of
aerating the wort, proper fermentations were achieved with only minor increases
in fermentation time. The beers produced from these fermentations were
comparable in flavor and foam retention to beers produced by traditional wort
aeration. The ester profiles of the beers produced using olive oil addition were
significantly higher than the controls, and the flavor stability of these beers
was significantly improved.
S�ntesis
Muchas cervecer�as est�n investigando maneras de reducir la introducci�n de
ox�geno a lo largo del proceso cervecero para extender la estabilidad sensorial
de sus cervezas. Sin embargo, se sigue practicando la aeraci�n del mosto antes
de iniciar la fermentaci�n, una pr�ctica casi universal en la industria
cervecera, puesto que el ox�geno es necesario para la reproducci�n y la salud de
la levadura. Estudios recientes han demostrado que m�todos alternos a la
aeraci�n tradicional del mosto (tales como la aeraci�n de la levadura antes de
dosificarla o la adici�n del �cido linole�co, un �cido l�pido no saturado)
pueden resultar en caracter�sticas de la fermentaci�n similares a la conseguida
con la aeraci�n del mosto, reduciendo la potencial de oxidaci�n del mosto. Aqu�
se reportan los resultados de una serie de pruebas a escala industrial
conducidas en una cervecer�a activa para evaluar los efectos de un tratamiento
alterno a la aeraci�n. Al agregar aceite de oliva a la levadura durante su
almacenamiento se obtuvieron fermentaciones normales (con un aumento muy peque�o
en el tiempo) sin airear el mosto. Estas cervezas fueron comparables en sabor y
retenci�n de espuma a cervezas producidas con la aeraci�n tradicional del mosto.
El perfil de �steres de cervezas elaboradas utilizando aceite de oliva era
significativamente mayor que el de los controles, y la estabilidad sensorial de
estas cervezas era significativamente mejor.
