Refermentation and maturation of lambic beer in bottles, a necessary step for gueuze production

The application of refermentation and maturation of blends of lambic beer in bottles is a common way of lambic brewers to cope with the high variability among different lambic beer batches. The resulting gueuze beers are much more carbonated than the lambic beers and are supposed to possess a unique flavor profile that varies over time. To map this refermentation and maturation process, a blend of lambic beers was made and bottled, whereby one of the lambic beers was produced with the old landrace Zeeuwse Witte. Through the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and high-throughput sequencing of bacterial and fungal amplicons, in combination with metabolite target analysis, new insights into gueuze production were obtained.