Today in 1971, US Patent 3625843 A was issued, another invention of Heinz Doevenspeck, for his “Method For Treating Beer.” There’s no Abstract, although in the description it includes this summary:

It is an object of the present invention to develop this prior art method and, in particular, to render it applicable with advantage to the treatment of liquids, preferably of beer. The method is intended to be developed in a manner as to enable the same to be carried out at temperatures of only about 25 C, thereby to prevent changes in flavor and color of the liquids to be treated and to obtain, at the same time, pasteurization and/or sterilization as well as stabilization of the liquids for the purpose of increasing the durability thereof.