Takahashi, M.1, Fukuhara, S.1, Yuki, K.1, Oga, T.1, Jimbo, E.1 and Yamagishi, H.1, (1)Quality Control Center, Asahi Breweries, Ltd., Moriya-shi, Ibaraki, JAPAN
Poster
“Beer gushing” is an undesirable phenomenon that occurs when beer and foam forcefully erupt from a beer bottle immediately after it is opened. Since this is a quality issue easily recognized by customers, there is the danger of serious damage to the company’s brand if such products are allowed on the market. Multiple causes of gushing are known, but the most frequent is contaminated malt, defined as a “primary gushing factor,” and thus discriminated from “secondary gushing factors.” At Asahi Breweries, malt crops that induce a gushing phenomenon are called “gushing malt.” A widely accepted method for predicting gushing potentials in malt samples is the modified Carlsberg method. This method is useful for evaluating malt samples themselves for the presence of gushing potentials, but it does not reveal any other gushing factors that may arise during beer manufacturing processes. In addition, the modified Carlsberg method sometimes lacks sufficient sensitivities, leading to false negative results for malt samples that exhibit undetectable gushing potentials by this approach. Under these backgrounds, Asahi Breweries, Ltd. has developed a new method for predicting malt gushing potentials, which entails a small-scale (200 mL) trial, mimicking the actual beer manufacturing process. As a consequence, this new method was shown to detect not only the gushing determinants present in malt itself, but also the gushing risks that become apparent during the beer manufacturing process. The comparative analysis also demonstrated that Asahi’s method is three times as sensitive as the modified Carlsberg method. In the course of examining over 100 malt crops in the preliminary testing stage, it was further found that some types of gushing malt crops exhibit high sensitivities to the metal iron released from the diatomaceous earth commonly used in the beer manufacturing process. As a consequence, these malt crops were shown to induce gushing when the iron concentration is above a certain level. Therefore, to predict the risk of iron-sensitive gushing malt crops, Asahi developed a modified method, in which the iron concentration is adjusted to the same level as that of beer products, using a specially blended diatomaceous earth for our small-scale predictive model. This modified method was shown to detect malt crops that exhibit iron-dependent gushing potentials. Moreover, the applications of our new method correctly identified the gushing potentials of malt crops that were affected by molds due to poor weather. Some of the examples included the 2007 and 2013 crops in Europe and North American crops produced since 2014. Taken collectively, our new method is useful for the highly sensitive and comprehensive detection of malt crops with gushing potentials. Through the monitoring for each lot of malt crops, Asahi Breweries has successfully introduced a system that prevents the use of malt that may cause gushing in beer manufacturing.
Miyuki Takahashi joined Asahi Breweries, Ltd. in 1997. Since 2002, she has been responsible for performing the analysis of alcoholic products and their raw materials to assure product quality. She has also been involved in developing new analytical methods and improving their reliability. She is currently a leader of the analytical group for alcoholic beverages and raw materials.
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