The Effect of Microporous Membrane Filtration on Beer Foam Stability
MBAA TQ vol. 41, no. 4, 2004, pp. 379-385 |
VIEW ARTICLE
Peter Riddell and Andrew Kelly. domnick hunter limited, Durham Road, Birtley, County Durham DH3 2SF, United Kingdom.
Abstract
Microporous membrane filters, designed to remove spoilage organisms and provide microbiological stability of beer, also remove any other suspended particles larger than the rated pore size. Additionally, they may be capable of removing colloidal and dissolved beer components, often to the detriment of the product. The described work studied the effect of membrane microfiltration on the foam stability of beer using 0.45- and 0.65-�m (pore size) retention ratings of two common, commercially available membranes�polyethersulfone (PES) and polyamide (PA). Four beers were chosen, representing a broad range of styles and recipes. Foam stability was expressed as the Rudin head retention value (RHRV) in seconds. The findings confirmed that membrane microfiltration could affect the foam stability of the beer. PA had a greater influence than did PES and, to a lesser extent, 0.45 �m had a greater influence than did 0.65 �m. There also were noticeable differences in the degree to which the various beers were affected. Follow-up areas of study designed to identify causal factors for depleted foam stability and to consider the relationship to the filtration volume have been suggested.
Keywords: filtration, foam stability, head retention, microfiltration, microporous membrane
The supplemental material includes a link to the brewing technical articles section on the domnick hunter website.
S�ntesis
Filtros con membranas de microporos para remover organismos da�inos y preservar la estabilidad microbiol�gica de cerveza, tambi�n remueven part�culas en suspensi�n con un tama�o mayor al de los poros. Es m�s, podr�an tambi�n remover part�culas coloidales y componentes disueltas en la cerveza, muchas veces en detrimento del producto. Se estudi� el efecto de la microfiltraci�n por membrana sobre la estabilidad de la espuma de la cerveza; se utilizaron dos tipos de membrana disponibles comercialmente�de polietersulfon (PES) y poliamida (PA)�con �ndices de retenci�n de 0.45 y 0.65 �m. Se utilizaron en las pruebas cuatro cervezas representando diversos tipos y recetas. La estabilidad de la espuma se expres� como el valor Rudin de retenci�n de espuma (RHRV, por sus siglas en ingl�s), en segundos. Se confirm� que la microfiltraci�n por membranas pod�a afectar la estabilidad de la espuma de cerveza. El efecto del PA fue mayor que el de PES, y el de 0.45 �m tuvo un poco mayor efecto que el de 0.65 �m. Se piensa estudiar en el futuro cuales son los factores causantes de la disminuci�n de esta estabilidad de la espuma, como tambi�n para determinar el efecto que tendr�a el volumen filtrado sobre este par�metro.
Palabras claves: filtraci�n, estabilidad de espuma, microfiltraci�n, membrana de microporos
