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The Influence of Elevated Germination Temperatures on the Resulting Malt Quality and Malting Losses - Part one
C. Mller, M. Kleinwchter, D. Selmar, and F.-J. Methner

The major goal for the malt industry is achieving a 'good' malt quality by means of high enzyme activities and a cytolytic modification to the greatest possible extent. For producing industrial scale malt batches of up to 300 tons, it also is greatly important to keep the energy costs and the malting losses as low as possible. Furthermore many possibilities have been investigated to reduce the production time to increase the capacity of the malting plants.Published findings claim that relatively low temperatures during steeping and germination (12-17 ?C) are required to produce high quality malt; however, these processes consequently take 5 to 7 days excluding the kilning. Applying higher temperatures were found to lead to raised malting losses and reduced extract yields. Most of these studies were carried out several decades ago and new barley varieties with improved malting properties are available now.In this study, constant germination temperatures between 16 and 28 ?C were used to obtain the influence of the temperature on the germination and thus the resulting malt quality and malting losses. Applying a germination temperature of up to 24 ?C compared to 16 ?C led to a faster start of germination, to an improved malt quality, and in particular to an enhanced cytolytic modification. Furthermore, an equal to improved homogeneity was achieved in a shorter germination time without markedly increasing the malting losses. The optimal germination temperature was detected to lie between 20 and 24 ?C. An observed reduced FAN content can be advantageous for improved flavour stability of beer produced of the malt due to fewer precursors for the formation of aging-related off-flavour compounds such as Strecker aldehydes. Furthermore, no lautering problems for the malt samples germinated at higher temperatures than 16 ?C could be detected. Outcomes from these trials benefit the malting industry in terms of potential energy and time savings without negatively affecting the malt quality. However, more barley varieties need to be tested and the results need to be verified.

Descriptors: germination temperature, malting losses, malt quality, cytolysis

BrewingScience - Monatsschrift fr Brauwissenschaft, 67 (March/April 2014), pp. 18-25