Beer Stability and Head Retention*

Abstract

On the basis of results of recent investigations of factors affecting beer stability, It is possible to make recommendations of procedures which will favour the produc tion of stable beer. The troublesome /9-globulin cannot be eliminated from barley during malting, but acidification of the mash to the isoelectric point of this protein (pH 4-9) gives encouraging results. Closed cooling systems favour stability, and avoidance of contact between the fermented beer and air is of the first importance. Kieselguhr is appropriate for pre-flltration, but centrifuging is not advisable when high stability is desired unless the problem of heating during treatment can be solved. Sheet filters alone should not be used for beers intended for pasteurization, but pulp filters are more efficient in removing chill-haze materials. Foaming properties are dependent on materials different from those responsible for nonbiological stability, so that theoretically it should be possible to improve stability without impairing foaming, though at present the differential treatment necessary to achieve this cannot be realized to the full.

Nitrogenous Constituents of Brewing Materials: V. Examination of the Action of Selected Precipitants on Brewers' Worts

“…refs. 6,7,8,15,34), and by the fact that the precipitants themselves lead to the degradation of certain compounds under the conditions employed. Later investigations on fractionating the nitrogenous constituents of worts have, therefore, been extended to include the study of the action of precipitants under mild conditions and of ion-exchange resins.…”

Non-Biological Haze in Bottled Beers: A Survey of the Literature

“…The disulphide bridge theory is supported by the high sulphur content of permanent haze, and the known presence of sulphydryl groups in j8globulin. 74 In addition, it is known that chill haze increases on storage at high tem peratures (30-50°C), suggesting that chemi cal combination is involved; however, no temperature coefficient has been quoted.87 >™ Physical properties.-Chill haze when freshly prepared is a material of pale grey colour which darkens rapidly on exposure to oxygen, whereas permanent haze material is dark red-brown in colour darkening to chocolate brown. The former is generally regarded as a reversible coagel, showing as a turbidity in beer at low temperatures (32-33°F.).…”