A Method of Detection for Residual Isinglass in Filtered and Cask-Conditioned Beers
Paul H. Chlup1, Kenneth A. Leiper1 and Graham G. Stewart1,2
1 International Centre for Brewing and Distilling, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, Scotland.
2 Corresponding author. E-mail: G.G.Stewart@hw.ac.uk
J. Inst. Brew. 112(1), 3–8, 2006 | VIEW ARTICLE
ABSTRACT
Isinglass has been used as a clarification agent in brewing for many years. However, recently its use has come under scrutiny. Due to concerns about food intolerance and food allergies, the EU and other government bodies have introduced legislation obliging food producers to declare those ingredients, additives and process aids, which are listed as allergens, on product labels. One of the affected products that is used in the brewing industry is isinglass. Within the EU, the brewing industry has objected to its inclusion as there is no evidence to suggest it is involved in food allergies. Due to this objection, isinglass has been granted exemption from the regulations for two years, to November 2007. During this time the industry must prove that isinglass is non-allergenic. This paper presents a simple and sensitive method for detecting the presence of isinglass in beer. The method involves hydrolysing beer samples with acid and mea-suring levels of hydroxyproline. This amino acid is found in isinglass but not in brewing raw materials. This method will be of use in any investigations involving isinglass. Data are pre-sented showing how the method can be used to test for the pres-ence or absence of isinglass in filtered and cask-conditioned beers.
Key words:
Cask-conditioning, filtration, hydroxyproline, isin-glass.
Publication no. G-2006-0320-309 ©2006 The Institute & Guild of Brewing