 After the boil, the beer was cooled and fermented in open wooden vats at 14 – 16°C (57 – 61°F). The two strains of yeast were added at the same time, and fermentation would proceed rapidly. After one day of fermentation, the thick foam that formed on the top of the fermentation vat was skimmed off and discarded. After 60 hours, up to 50 % of the available sugars would have been fermented by the yeast, and thick clumps of yeast were skimmed off of the surface and harvested for reuse. The beer was then pumped with sterile air into clarification tanks. Isinglass was added to clarify the beverage, and then it was bottled.
