VUB research lambic beer: less nostalgic than often thought
Taste and character mainly determined by micro-organism, less by grains used
In his PhD at the VUB, "Lambic beer production: impact of traditional wheat varieties and maturation, and identification of inoculation sources", Dries Bongaerts (Research Group Industrial Microbiology and Food Biotechnology) investigated how the changing production process, and especially the use of other grain varieties, affects the age-old production of lambic. Bongaerts studied how those changes affect the production and taste of lambic.
Lambic is a beer with a history dating back to the 16th century. It is characterised by spontaneous fermentation, the use of unmalted wheat and a maturation that can last up to three years in wooden barrels. Although the production process has remained largely unchanged, the ingredients have evolved over time. Whereas brewers used to use local wheat varieties in the past, today they mainly use modern wheat varieties from the world market.
The research shows that it is not so much the raw materials but mainly the environment and the production process that determine the final result. "We saw that not the raw materials, but the spontaneous inoculation and process conditions are the most important factors for the outcome of the lambic beer production process," says Bongaerts. In other words, the microorganisms that spontaneously enter the beer and the way the beer matures play a decisive role in flavour and character.
The research mapped exactly where those micro-organisms come from. The wooden barrels in which lambic ferments and matures proved to be a crucial source, as did the so-called 'house microbiota' in the brewery itself. "The wooden barrels and the microorganisms in the brewery air and on surfaces such as walls and ceilings are the main sources of inoculation," Bongaerts explains. This unique microbial environment helps create the typical character of lambic.
In addition, the research shows that lambic continues to evolve even after bottling. During re-fermentation and maturation in the bottle, the flavour changes further due to the activity of specific yeasts. "The flavour of lambic can still change during re-fermentation and maturation in glass bottles, mainly due to the continued metabolism of Brettanomyces yeasts," Bongaerts said.
About the researcher
Dries Bongaerts holds a master's degree in bioengineering and a master's degree in business administration from VUB. He carried out his PhD at the VUB within the Industrial Microbiology and Food Biotechnology Research Group, in collaboration with a lambic brewery, with support from the VUB Research Council and the SME portfolio (VLAIO). He has co-authored six scientific publications in international peer-reviewed journals. Through his research, he contributes to a better understanding of one of Belgium's most authentic beer traditions and helps preserve and strengthen knowledge around lambic production for the future.
More info:
Dries Bongaerts: dries.bongaerts@vub.be
https://cris.vub.be/ws/portalfiles/portal/225259769/Dries_Bongaerts_PhD_thesis.pdf
