Q&A: VIB scientists trace domestication of beer yeasts

Why are yeasts so important in beer and wine production?
Yeasts are micro-organisms that can convert sugars into alcohol, carbon dioxide and aroma compounds – thus giving specific flavours and aromas to beer and wine. With the help of the VIB bio-informatics team at Ghent University, we determined the origins of about 150 yeasts. Most of these were developed in Belgium, but we also analysed yeasts from other European countries and the US.

Did early beer brewers realise what yeasts were doing?
We discovered that brewers as far back as the 16th century were domesticating yeasts, so before the actual discovery of what micro-organisms were, which occurred a century later. People have been making beer for about 8,000 years, but the craft became more commercial and professional in the 16th century.

What do you mean by “domesticating” yeasts?
The brewers kept a small part of a previous brew that had fermented well to mix it with a new batch, which made the fermentation process quicker and more consistent. Without realising it, they were selecting and transferring yeast cultures from one batch to the next, allowing the microbes to continuously adapt to the man-made environments. This domestication process is very similar to what humans did with livestock, crops and pets like cats and dogs.

Is there a difference between beer and wine yeasts?
Wine yeasts show fewer signs of domestication, probably because they are only used to ferment grape juice once a year and for the rest of the year survive in and around the winery – where they can interbreed with wild yeasts. You could say that beer yeasts are like dogs, “tamed” and adapted to their relationship with humans, while wine yeast have the wilder character of cats.

How can these insights be put to use?
We can use the information to create better yeast variants, further improving the flavour and aroma of beers and wine. The results of our previous yeast research is actually already applied by brewers to enhance their products, but these new findings will further boost our collaborative efforts.