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The research brewery at the Institute of Electrochemistry at Clausthal University of Technology focuses on mashing at constant temperatures of more than 72 °C, which has been little known up to now. In a conventional brewing process, many breweries today use a more or less predetermined temperature program for mashing.
Crushed malt is mashed at approx. 55 °C and then subjected to a "protein rest" at 52 - 55 °C, during which the proteins not yet dissolved in the malting process are further broken down by enzymes present in the malt for 15 - 20 minutes. In this way, amino acids are produced that the yeast needs for later fermentation, as well as proteins that stabilize the foam of a beer.
Today's malts, which are further developed from year to year through breeding, are already so well dissolved during the malting process in malting plants that this protein rest can also be omitted, and many large breweries skip the protein rest and mash directly at approx. 65 °C. In this range, the beta-amino acids in the malt can be reduced to a minimum. In this range, beta-amylase (from the malt) is active, which releases the sugars glucose, maltose and maltotriose, which can be fermented by most yeasts, from starch. At approx. 72 °C, the alpha-amylase from the malt is again highly active, releasing glucose, maltose and maltotriose from the starch in the malt, albeit in smaller quantities, but also higher non-fermentable sugars up to the so-called dextrins.
The consequence of such a mashing process is that a typical Pilsner beer with an average original gravity of 11.5 °P (that is 115 g of dissolved substances in one kilogram of unfermented wort) contains around 5% alcohol by volume.
We asked ourselves what would happen if the resting temperature of 65 °C was also omitted and malt was mashed in such a way that a constant temperature of 72 °C was maintained during mashing, because at this temperature the activity of beta-amylase drops to almost zero within a short time. These experiments showed that the amount of fermentable sugars is reduced and the amount of non-fermentable sugars is increased, and a Pilsner beer with an original gravity of 11.5 °P achieves an alcohol content of only around 3.5% by volume with this process.
If dark malts such as "Munich malt" are used in combination with dark caramel malts, beers with alcohol contents of around 2.5% by volume are obtained at 11.5 °P. Together with the Research Center for Brewing and Food Quality at the Technical University of Munich, we are also looking at the potential of this little-known mashing process in combination with maltose- or maltotriose-negative yeasts.
In another topic, we are trying to develop tasty but gluten-free beers with a special type of quinoa grown by a farmer in the foothills of the Harz Mountains, which are similar in taste to classic beers.