Rainier Develops the Unitank for Fermentation and Maturation

In 1968, Rainier Brewery in Seattle developed a vessel known as the unitank for carrying out fermentation and maturation in the same tank. Its relatively squat proportions and shallow conical bottom distinguished it from the taller Nathan-type vessel. Cooling equipment handled both the heat released during fermentation and the subsequent chilling needed for maturation. The unitank joined stages commonly divided between fermentation and lagering cellars, reducing the need to transfer beer between vessels. Its name described a way of organizing production as well as a tank design. Although unitanks became closely associated with cylindroconical fermenters, the two terms emphasize different things: one-vessel processing and vessel geometry. Rainier’s development was therefore a distinct step within the longer history of enclosed fermentation.