The influence of the polyphenols on the chill stability of beer
K. Silbereisen and F. Kraffczyk
The chill stability of different beers was reduced by half on the addition of 20 to 40 mg/litre of procyanidin which was isolated from barley. However, some beers to which 40-50 mg/litre of procyanidin was added, exhibit a remarkable stability compared with other beers. Anthocyanogens, therefore, are not the only influence on chill stability. The haze-forming effect of procyanidin solutions is enhanced when they are exposed to air for some days. The same is true for catechin solutions, but under the same conditions these have not as great an effect as procyanidin solutions. Determination of procyanidins does not measure this change. In the determination, the extinction slowly falls with rapid increase in tanning power of the procyanidin. From the quantitative determination of anthocyanogenus in a beer as carried out at present, it is not possible to assess the influence of these substances on the chill stability of that beer.