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The Speaker's Corner at BrauBeviale is aimed at those who think they could still learn something about beer and brewing: for example, about the brewing process for non-alcoholic beer, writing good sensory characteristics information, or proper networking.
We talked to biochemist and master brewer Andrew Paterson from Lallemand about how to brew non-alcoholic or low-alcohol beer without additional equipment.
BrauBeviale: Mr Paterson, how do you brew non-alcoholic or low-alcohol craft beer without having to buy expensive equipment for dealcoholisation?
Andrew Paterson: If you want non-alcoholic beer, there is no way around large investments. But low-alcohol beer can be brewed without special equipment. You just need the right settings during the brewing process.
Alcohol in beer is produced because yeast ferments the sugar in the mash, producing carbon dioxide and alcohol.
That’s true, but not every yeast can do this equally well. It mainly depends on how long the chains of sugar molecules are. Most brewing yeasts can only digest simple (monosaccharide) or double (disaccharide) sugars, i.e. glucose and maltose. Some also manage to digest maltotriose, which consists of three sugar molecules (a trisaccharide). But that's all. Everything else can only be done by yeasts that are not brewing yeasts. However, during mashing, you can influence how much of these types of sugars are produced.
Now we need a little biochemical digression.
At the beginning of the mashing process, there is no sugar at all: only the starch from the malted barley grains. Starch consists of many sugar molecules linked together (a polysaccharide). Two enzymes then come into play, alpha- and beta-amylase, which split the starch into the smaller sugar molecules. The latter is mainly responsible for producing very short sugar molecules. But at high mash temperatures, this enzyme is destroyed and the starch division slows down.
So, can you simply set the boiler up to the maximum temperature?
No! If the temperature is too hot, too much starch will remain in the mash, and this needs to be avoided too. In an experiment, we tested five different mash temperatures from 86–95°C and with four different durations. The sugar profile was best at 82°C and a 60-minute mashing time.
What does that mean for the alcohol content in the finished beer?
Conventional brewing yeasts can be used with this method to brew beers with 0.7% ABV. Maltotriose-spurning yeasts, such as our Windsor or London varieties, can be used in the same way to achieve beer with 0.6% ABV.
Is there anything else that brewers need to consider when mashing at such high temperatures?
They mustn’t lose control of the pH value, which will rise much more than normal. You have to counteract this with acidity or dark malts.
And have you already brewed beer with this hot mash method?
Not ourselves, but Good Things Brewing has developed a recipe following our findings and brewed a rather hoppy pale ale. Not at 82°C, but at 78°C – so there was a little more alcohol in the final product. Personally, I’m really happy with the product and it was well received by attendees at BrauBeviale 2019.