Today in 1968, US Patent 3484244 A was issued, an invention of Peter D. Bayne and Joseph A. Kozulis, assigned to Schlitz Brewing Co., for their “Fermenting and Aging a Malt Beverage.” There’s no Abstract, although in the description it includes this summary:

This invention relates to a method of brewing and more particularly to a method of fermenting and aging a malt beverage.

The present invention is directed to a method of fermenting and aging at malt beverage which is based on a concept directly opposed to traditional brewing practices. More specifically, the wort is introduced into a tank and pitched with yeast. Following the addition of yeast, the Wort is continuously circulated from the tank to a heat exchanger and returned to the tank in a closed flow system. A cooling medium is supplied to the heat exchanger to maintain the wort at a temperature in the range of 45 to 70 F. during the fermentation process.

When the fermentation has proceeded to a point where the specific gravity of the wort falls to a predetermined value below 5 Plato the supply of the cooling medium to the heat exchanger is terminated and the fermented wort circulating within the closed system will gradually increase in temperature due to the heat generated by the fermentation process. The temperature of the fermented wort is permitted to rise until it reaches a value at least 4 above the fermenting temperature, and generally in the range of 50 to F., and is maintained at this temperature by controlled circulation of the cooling medium. At this time the yeast is still present in the beer and the beer is continuously circulated through the system for a period of about one to five days and until the diacetyl content falls to a value below 0.2 p.p.m. and the acetaldehyde content decreases to a value below 5 p.p.m. At this time, the beer is considered to be fully aged or matured.

At the end of the maturation cycle, the temperature of the circulating beer is reduced to a value of about 29 to 32 F. approaching the freezing point of beer. With the beer at this temperature, the beer is withdrawn from the tank and pumped through a centrifuge to re move the yeast. Following the removal of yeast, the beer is prefiltered and carbonated, injected with enzymes, and other additives, polish filtered, the carbonation adjusted and then is stored in government storage tanks for packaging in accordance with conventional brewing procedures. In some instances, only one filtration may be necessary to prepare the beer for packaging.

Today in 1964, US Patent 3161522 A was issued, an invention of John Compton, for his “Continuous Lautering Of Brewer’s Wort.” There’s no Abstract, although in the description it includes this summary:

This invention relates to a method of lautering, i.e., straining and recovery of wort liquid from mash grains in the brewing of beer. Lautering has been one of the most critical of the numerous operations involved in brewing and has heretofore required a great amount of skill and experience on the part of the operator to produce quality beer without lost time.

This method may generally be defined as a method of continuous lautering which comprises the steps of feeding a mixture of grains and wort liquid from a mashing operation in a brewing process onto the upper flight of a moving continuous perforated belt at a point adjacent one end of said upper flight, regulating the speed of said belt, and the rate of feed of the mash thereon to, to form a filtering bed of grains on said belt, collecting a filtrate of clear wort liquid which has passed downwardly through said grains and through the upper flight of said perforate belt, subjecting the filtering bed to water-spraying to sparge out residual sugar values and removing said bed of grains from said belt in the region of the other end of said upper flight.

Today in 1957, US Patent 2816031 A was issued, an invention of Wilhelm Eberhard Schultheis and Walter Specht, assigned to Ultra Technik G M B H, for his “Beer Brewing Process.” There’s no Abstract, although in the description it includes this summary:

We have found that the production of beer may be made more economical and that beers of superior qualities may be obtained by the application of ultrasonic waves, which term is generally understood to define waves whose frequencies are greater than those which affect the human ear, that is, greater than about 18,000 per second. The ultrasonic irradiation, called hereinafter sonoration, may be applied to various stages of the brewing process. For instance, hops in the presence of water or aqueous solutions, intermediary products such as mash, wort, glattwasser (last wort), or by-products, such as trub, may be treated, singly or severally, also in mixture with each other, with ultrasonic waves to obtain advantages.

As an ultrasonic generator, e. g. the immersion device type T 300a, rotation irradiator with high frequency generator (1000 kilocycles), built by Ultrakust G. m. b; H., Ruhmannsfelden, Lower Bavaria, may be used. The apparatus is preferably operated with full output, whereby it transmits about 300 watts ultrasonic energy to the treated batch.

The sonorat-ion is preferably carried out at elevated temperatures, e. g. between about 50 to 100 (3., which temperatures should be kept constant, and with at least temporary circulation of the treated solution.

A well known drawback of the conventional hopping process, where hops as such are added to the wort, is due to the fact that in the boiling process only about one-third or one-fourth, generally not more than 35 percent, of the bitter principal ‘(resins) contained in the hops pass into the wort, and that, in addition, considerable amounts, e. g. about 3 to 7 percent, of aid resins are precipitated during fermentation and storage.

According to the invention, these drawbacks are obviated by subjecting hops to sonoration in the presence of water or aqueous solutions, e. g. softened brewing water, wort, or last wort; hereby the valuable resins of the hops are dispersed in the extracting liquid without objection: able loss, and the thus obtained resin extracts are used for hopping the wort.

As the hop resins are difficulty soluble in water, only limited amounts of said resins can be dissolved in the water or aqueous solutions used as solvents. In addition, the dissolved resins readily precipitate again, particularly in the presence of absorbent substances, such as spent hops, trub, yeast, or carbon dioxide bubbles. The separation of the resins is further assisted by the fact that the pH of the sweet wort changes during fermentation from United States Patent 2 5.5 to about 4.5, which reduces the solubility of the resins.

We have found that ultrasonic waves have the elfect of producing a fine colloidal dispersion of the difficulty soluble resins in the extract, and at the same time, a stabilization against objection-able precipitation of said dispersed resins in the extract and later in the wort. We believe that this stabilizing action is due to colloidal substances which pass by the sonoration together with the resins into the aqueous liquid, and also to colloidal substance contained in the wort; This may explain the phenomenon that res-ins isolated by sonoration from the hops and dispersed in the aqueous phase can be concentrated in the extract; even in the acid range, to a considerable’ extent and that on addition of the resin extracts thus obtained to the boiling wort objectionable precipitation of resins is substantially avoided. Therefore, the resins are essentially retained in the wort and do not pass, to the extent experienced heretofore, into the trub or during fermentation into the so-called curls or into the yeast.

The extraction of the resins by scnoration may be carried out separately in a metal vessel of a suitable size for the hatch, e. g. in the hop strainer available in breweries, and the resin extract thus obtained will be admixed to the wort in suitable amounts. For instance, we may mix the allotted amount of hops with the extracting liquid, which has been heated to about 50 to 60 C. or even higher, and first agitate the mixture, for instance by circulator, for several minutes to obtain swelling and only subsequently start the sonoration. As extracting liquid, we may use decarbonate’d brewing water, or the glattwasset (last wort) obtained by washing (sparging) the spent grains separated from the first wort, or even the first wort itself. The amount of liquid to be added to the hops depends on the desired concentration ratio between hops arid liquid. In determining the optimum working conditions, it must be taken into account that the maximum extraction effect is not only dependent on said concentration ratio, but also on the nature and composition of the extraction liquid, the pH value, the extraction temperature, the ultrasonic intensity and the sonoration time. Our experiments were carried out at a temperature of about 5060 C. and the temperature was kept constant throughout the extraction period. Under these conditions, a sonoration period of about one hour lproved generally to be sufficient; sometimes it was necessary to apply a somewhat longer sonoration, e.g. up to two hours, in order to obtain optimum results. The extraction by means of sonoration may, however, be carried through also at higher temperatures, e. g. between 60 and C. with a shortened sonoration.

After completion of the extraction, the resinous extract may be separated from the spent hops, e.g. by filtering with suction, and separately processed.