Today in 1974, US Patent 3814003 A was issued, an invention of Nickolas Lothar Vacano, assigned to Rainier Companies, for his “Brewing Apparatus.” Here’s the Abstract:

A large size thin-shelled outdoor metal tank, such as for making beer, with a conical metal bottom having a shallow slope of no more than 25 DEG from the horizontal, a conduit communicating with the tank interior at the apex of the conical bottom, a circular cylindrical vertical metal wall joined to the bottom, a metal roof joined to and supported by the vertical wall, insulation exterior of the bottom, wall and roof, a vent opening in the roof, a manifold centrally located in the tank spaced above the bottom and the level of unsuspended solids which may settle therein, said manifold having a plurality of openings through which carbon dioxide gas can exit into liquid in the tank, and a pipe leading from outside the tank to the manifold for supplying carbon dioxide thereto. The tank can have a tubular ring positioned inside the tank adjacent the periphery of the bottom, a pipe communicating with the ring and the exterior of the tank for supplying fluid to the ring, and a plurality of holes in the ring from which fluid under pressure can be ejected along the slope of the bottom to wash solids to the conduit in the bottom for removal.