Belgium’s world-famous lambic beer owes its characteristic flavour primarily to microorganisms, and much less to the grains selected, doctoral researcher Dries Bongaerts (VUB ) says after conducting scientific research at the Flemish Free University of Brussels, the VUB. This explains why the flavor has remained remarkably stable over the years, even though the grains used have changed several times. The brewing environment and the wooden barrels play a particularly important role.
Lambic beer owes unique flavour primarily to microorganisms (and much less to the grains used)
Colin Clapson
Published:
Lambic enthusiasts know that it is a traditional Belgian beer that undergoes spontaneous fermentation. Before it is bottled, it matures for up to three years in wooden barrels.
It is a typical regional beer brewed primarily in the Pajottenland region, southwest of Brussels. Nowadays it is also brewed by a few breweries outside that region, notably in West Flanders Province.
Today it is made with unmalted wheat, but that was not always the case. Throughout the brew’s centuries-old history, various grains have been used. But according to Bongaerts, these had little effect on the beer’s flavour.
Microorganisms determine the flavour
The researcher devoted his doctoral thesis to the study of the evolution of flavour. He concluded that it is not grains, but rather microorganisms that largely determine the flavour. This is due to so-called “spontaneous inoculation,” or the natural introduction of yeasts and bacteria. These largely determine the final result.
Wooden barrels and the brewery environment, in particular, appear to be crucial sources of such microorganisms. In addition, the brewery environment itself is also important. “The air, walls, ceilings, and other surfaces collectively harbour a unique in-house microbiota,” says Bongaerts.
The flavor continues to evolve in the bottle
It is also striking that lambic is not “finished” after bottling: the flavour continues to evolve. During secondary fermentation and further bottle aging, the flavour keeps changing.
Through his research, Bongaerts aims not only to provide scientific insights but also practical knowledge for brewers. In this way, he hopes better to understand the tradition of lambic and prepare it for the future.
Bongaerts completed his PhD at the Flemish Free University of Brussels, the VUB, in the Industrial Microbiology and Food Biotechnology research group, where he collaborated with a lambic brewery.