Today in 1959, US Patent 2898209 A was issued, an invention of James E. Grant, Charles J. Krueck, Milton E. Lavrich, Justin J. Murtaugh, and Donald G. Ruff, assigned to the Blatz Brewing Company, for their “Method of Extracting Hops.” There’s no Abstract, although in the description it includes this summary:
Our invention relates to a new and improved hop extract; to a new and improved method of making a hop extract; and to a new and improved hopped beverage, such as alcoholic malt beverages exemplified by beer and ale.
While the invention applies to the treatment of any part of the hop plant, it refers particularly to the treatment of the cones of the hop plant. These cones are preferably extracted in the whole state, but they may be cut, ground, or otherwise comminuted.
After a lengthy discussion, in the last page of the application, they set forth their claims, summarized:
1. A method of extracting solid starting material, said stafting material having substantially the composition of vine-fresh hops, which consists in extracting said material with methanol at a maximum temperature of 65 C. to produce an original liquid extract of said starting ina– terial, said original liquid extract including water which is extracted from said starting material, said water being mixed with said methanol in said original liquid extract, said original liquid extract including water-insoluble and methanol-soluble material which is extracted from said solid starting material and which is dissolved in the methanol of said original liquid extract, said original liquid extract including water-soluble and methanol-insoluble material which is extracted from said solid starting material and which is dissolved in the water of said original liquid extract, said methanol-soluble and waterinsoluble extracted material including alpha-resin and beta-resin, the weight of said alpha resin being at least 40% of the weight of the total soft resin; separating said original liquid extract from the undissolved, residual part of said starting material; flowing the separated, original liquid extract forwardly through an externally heated zone in the form of a thin, rapidly forwardly-flowing stream to heat said forwardly-flowing stream substantially uniformly within’ said heating Zone without substantially evaporating methanol or water from said forwardly-flowing stream within said heating zone, forwardly flowing said forwardlyflowing stream within said heating zone at a sufliciently high velocity to substantially prevent the solutes of said forwardly-flowing stream from coating the inner face of said heating zone; flowing said forwardly-flowing stream out of the outlet of said heating zone into an evaporation chamber; evaporating a part of the methanol and water in said evaporation chamber from the stream which is flowed into said evaporation chamber and thus providing a residue of said stream within said evaporation chamber, flowing the evaporated methanol and water out of said evaporation chamber; flowing the residue of said stream out of said evaporation chamber forwardly through said heating zone and back into said evaporation chamber in cyclic succession while evaporating a part of the methanol and water from the stream which is flowed into said evaporation chamber during each cycle and flowing the part of the methanol and water which is thus evaporated durmg each cycle out of said evaporating chamber, maintaining said evaporation chamber at a maximum temperature of substantially 65 C. and at a maximum pressure of substantially millimeters of mercury, and continuing said cyclic succession to produce a concentrate of said original extract in which the weight of said alpha-resin is at least 40% of the weight of the total soft resin.
2. A method according to claim 1 in which substantially all the methanol is evaporated in said cyclic succe’ssi’on within said evaporation chamber from said original extract.
3. A method according to claim 1, in which the cyclic succession is stopped when said concentrate includes an aqueous phase of residual water and a non aqueous methanol resin phase in which said resins are dissolved, and said aqueous phase is separated from said methanol resin phase. I
4. A method according to claim 3, in which said aqueous phase is separated from said methanol resin phase by dissolving a water-soluble salting-out agent in said aqueous phase.
5. A method according to claim 3, in which the weight of said aqueous phase is at least substantially 70% of the weight of said concentrate.