Today in 1973, US Patent 3773222 A was issued, an invention of Erich Fiebinger, assigned to Draft Systems, Inc., for his beer yeast “Dosing Installation.” Here’s the Abstract:

A dosing system for continuously dosing and dispensing the respective quantities of auxiliary filtering substances to be added in connection with a settling filtration to a cloudy liquid, especially beer, for the cooling and yeast sediments, according to which for dispensing an auxiliary filtering substance for the cooling sediments as well as an auxiliary filtering for the yeast sediment there is provided one dosing device each equipped with a flow meter while both devices which are directly connected to the cloudy liquid conveying conduit are preceded by a flow meter and a device for measuring the total cloudiness of the liquid and by a measuring device provided with a heating zone for measuring the yeast sediment in the cloudy liquid conveying conduit. The dosing installation includes a control device for controlling the dosing devices in conformity with the cloudiness measured by the respective devices.