Leopold Nathan and Hans Bolze Patent an Enclosed Brewing System

On September 29, 1908, Leopold Nathan and Hans Bolze received U.S. Patent 899,756, “Process of Brewing Beer,” following an application filed in 1901. Their process used closed, sterilizable equipment, including an enamel-lined vessel with a heating-and-cooling jacket and an agitator. It sought to control fermentation and accelerate the treatment of young beer. Nathan’s wider work developed enclosed vertical vessels with cylindrical bodies and conical bases, connecting fermentation control with sediment removal and conditioning. Nathan’s work was an important early stage in the development of enclosed vertical fermentation technology. Later cylindroconical tanks adopted related geometry and operational advantages, but modern CCT practice emerged through further changes in vessel scale, cooling, cleaning, pressure control, and process design. The patent therefore marks a significant precursor, not the solitary invention of the modern CCT.