Improving Hop Utilization And Flavor Control Through The Use Of Pre-isomerized Products In The Brewery Kettle
MBAA TQ vol. 38, Number 1, 2001, Pages 11-21 |
VIEW ARTICLE
Richard J. H. Wilson (1), T. Roberts (1), R. J. Smith
(2), and M. Biendl (3). 1. Steiner Hops Ltd., Epping, Essex, UK. 2. S.S. Steiner, Inc., Yakima, Washington,
USA. 3. Hallertauer Hopveredelungsgesellschaft mbH, Mainburg, Germany. Paper presented at the World Brewing Congress 2000, Orlando, Florida, USA.
Abstract
Many breweries now brew with isomerized hop pellets, eliminating about one third of their former purchase of bittering hops and an even greater part of their aroma hops, at the same time gaining the ability to vary the hoppy flavor of beer without risk of losing economic advantage. The same principles can be applied to hop extracts. A CO(2) extract of hops was converted into two forms of isomerized kettle extract. In the first, "IKE", the original
alpha-acids were converted into iso-alpha-acids, while in the second, "PIKE", these were further changed into their K(^+) salt forms, yielding a product that was rapidly dispersible into hot wort. Pilot brewing trials showed that utilization values were thereby greatly increased, without apparent change to the beer flavor. Moreover, late addition to the kettle resulted in similar enhancement of hop oil
components to the beer as for a CO(2) extract control brew. And even when the late addition portion of the PIKE was added only at the end of the boil, utilization of the iso-alpha-acids remained very high. The production of lightstable beers is commonly achieved via use of bitterness derived solely from post-fermentation addition of reduced,
isomerized alpha-acids. However, this does pose the risk of encountering serious wort infections. Further brewing studies showed that the addition to the kettle of a CO(2) extract in which the
alpha-acids had been converted into rho-iso-alpha-acids still allowed the achievement of high utilizations and the resultant beers were found to be similar to that produced by use of normal CO(2) extract, excepting only that the bittering component was necessarily different. These beers were also found to have substantially enhanced resistance to the formation of
"sunstruck" flavor.
Keywords: Isomerized alpha-acids, reduced iso-alpha-acids, kettle hop extract, bittering, hop utilization, light-struck flavor.
S�ntesis
Muchas cervecer�as ahora elaboran la cerveza con bolitas de l�pulo isomerizadas, eliminando cerca de una tercera parte de la compra de
l�pulo para amargar y una parte todav�a mayor de sus l�pulos de aroma, al mismo tiempo ganando la habilidad de variar el sabor de l�pulo de la cerveza sin arriesgar el perder la ventaja econ�mica. Los mismos principios se pueden aplicar a los extractos de l�pulos. Un extracto de CO(2) de los l�pulos se convirti� en dos formas de extracto de hervidor isomerizado. En el primero o "IKE", los �cidos
alfa fueron convertidos en is�meros de �cidos alfa, mientras que en el segundo, "PIKE", estos fueron convertidos en forma de sus sales de potasio, produciendo as� un producto que se dispersa r�pidamente en mosto caliente. Estudios piloto de elaboraci�n de cerveza mostraron que los valores de utilizaci�n se incrementaron grandemente, sin cambio aparente al sabor de la cerveza. Es m�s, la adici�n tard�a al hervidor result� en un realce similar de los componentes de aceite del mosto a la cerveza de acuerdo a un
control del extracto de CO(2) . A�n cuando la porci�n de adici�n tard�a del PIKE se a�ad�a solo al final del proceso de hervido, el uso de los isomeros de los �cidos
alfa se mantuvo muy alto. La producci�n de cervezas estables a la luz se consigue com�nmente mediante el uso de la amargura derivada solamente de la adici�n de la posfermentaci�n de �cidos
alfa isomerizados reducidos. Sin embargo, esto tiene el riesgo de encontrar infecciones de mosto serias. Estudios de la elaboraci�n de la cerveza mostraron que la adici�n de extracto de CO(2) al hervidor en el cual los �cidos
alfa han sido convertidos en �cidos rho-iso-alfa-aun permitieron lograr un uso alto y las cervezas resultantes fueron
similares a las producidas mediante el uso de extracto de CO(2) normal, con la excepci�n de que el componente de amargura era diferente. Estas cervezas tambi�n resultaron tener una resistencia substancialmente aumentada a la formaci�n de un sabor de
"insolaci�n".
