Joan Montasell, Lallemand, Milwaukee, WI, U.S.A.
Coauthor(s): Sylvie Van Zandycke,
Yeast, Fermentation, and Microbiology II
Thursday, October 12
Sour beers are by no means a new style; before the advent of microbiology all beers were slightly sour due to the presence of wild yeast and bacteria. It was only after the implementation of modern day beer-making techniques that brewers were able to control flavor outcome. Sour beers are experiencing a renaissance these days; examples of the style are American Wild Ale, Berliner Weisse, Flanders Red Ale, Gose, Lambic, and Oud Bruin. The market is growing and consumers are demanding more variety and organoleptic experience. Sour beers can be made using several techniques with the souring culture introduced either before or after wort boiling. Sour mashing and wort souring are both performed prior to wort boiling. During sour mashing the wort is left in the mash tun for 1–3 days at temperatures between 45 °C and 49 °C before sparging and inoculated with a pure culture of Lactobacillus or uncooked grains (naturally containing bacteria and wild yeast); then, the boil proceeds as usual. Wort souring follows the same concept but is performed after sparging. For both methods it is advisable to pasteurize the wort. The availability of Lactobacillus cultures in freeze-dry form provides a means of souring wort rapidly and reproducibly using a convenient addition system. In the present study, different lactic acid bacteria cultures were evaluated for their acidification properties and flavor profile. The target was to achieve pH 3.5 or lower within 48 hours of fermentation with high lactic acid and low acetic acid concentrations. The selected culture was used in a brewery setting and various parameters were measured (i.e., pH, time, lactic/acetic acid, sensory, etc.) to ensure successful souring and the development of an exciting product. The practicality of a selected freeze-dried culture of bacteria will be highlighted.
Joan Montasell is Lallemand Brewing’s technical sales manager in Spain. He previously worked as head brewer for Haandbryggeriet (Norway) and as R&D technician for Mahou-San Miguel (Spain). His passion for brewing brought him to study in Belgium, Denmark, the UK, and the U.S.A., and he is currently waiting for his IBD Diploma in Brewing.