Characterization of Frozen Beer Precipitates from Single Packages. K. E. Skinner, B. C. Hardwick, and R. B. Saha, Brewing Technical Services, Anheuser-Busch Inc., One Busch Place, St. Louis, MO. J. Am. Soc. Brew. Chem. 51:0058, 1993.

When beer is inadvertently frozen, either in the retail marketplace or in the home of the consumer, an unsightly, cloudy product containing white to off-white flakes or strings is sometimes observed on thawing. The appearance of this beer can lead to consumer complaints. It is important that laboratories concerned with consumer complaints are able to distinguish these naturally occurring precipitates from those not derived from normal beer. The need to identify and characterize these precipitates was addressed by adapting and developing a series of qualitative and quantitative assays that can be used to analyze the amount of precipitate found in a single package. The precipitates were characterized qualitatively by microscopic and infrared spectroscopic methods. Quantitative assays employing a variety of wet chemical, enzymatic, or inductively coupled plasma spectrophotometric methods were used to analyze the precipitates found in 30 beer packages that had been frozen.

Keywords: β-Glucan, Calcium oxalate, Frozen beer precipitates, Protein