VIB-K.U.Leuven scientist Kevin Verstrepen develops a tailor-made yeast for beer with more flavour

19 January 2011

“We want you to create a strain of yeast for a very special kind of beer. It has to have a lot character, but it shouldn't be too heavy.” This was beer brewer Bart Landuyt's assignment for the lab of Kevin Verstrepen, one of VIB's yeast specialists.

By crossing various yeasts with each other, Verstrepen, who works for VIB and K.U.Leuven, managed to obtain a tailor-made yeast which had exactly the properties that the brewer was looking for. The beer, known as Tumulus 800, is now ready for marketing. It was launched on 22 January 2011 in Landen as a festive beer to celebrate the 800th anniversary of Landen and will be available for tasting at the Patroons festival of the Katholieke Universiteit Leuven on 2 February.

Kevin Verstrepen: “My laboratory uses brewer's yeast as a model for genetic processes in complex cells. At the same time, Dr Sofie Saerens leads a group in the laboratory that makes yeasts for industrial applications. This ranges from the production of beer, wine, bread and chocolate to bio ethanol and medicines.” The laboratory has a collection of hundreds of yeasts, from the most varied environments, from collections of friendly scientists and breweries or from trees and rotting fruit.  

Bart Landuyt, a K.U.Leuven scientist who also brews beer in his spare time, contacted the laboratory. “During my studies to become a bio-engineer, I chose beer brewing as a specialisation. Together with a number of amateur brewers, we had been brewing beer for our own consumption for some time. From the start, we did not intend to copy any existing beers but to brew modern beers using scientific methods.”

“Our first beer - Tumulus Magna - had a alcohol content of 9%. We were asked to come up with a beer with a lower alcohol content - a light, easy to drink type of beer that could be consumed at receptions," says Landuyt. He started looking for a beer with character, which usually means bitterness, without being too heavy. To achieve this, he called upon Kevin Verstrepen. The recipe for the new beer was tried out in the laboratory using various yeast bases, says Verstrepen. “We crossed various yeasts with each other to obtain a super yeast with exactly those properties that the brewer wanted. In this case, we obtained a yeast which makes a great deal of aromas but at the same time with a very high yeasting level. In this way, you get a beer with many aromas that is nevertheless extremely drinkable". 

The chemical analysis of the aroma components, rather than the tasting, was crucial in choosing the yeast explains Landuyt. “On the basis of that investigation, we chose the yeast base with the most fruity aroma. If you smell the new beer, you can detect traces of apple, pear, lychee and banana. Even some flower aromas.” In this way, a refreshing beer for hot days was born - Tumulus 800, a bitter blond full malt beer with 6% alcohol content.