Today in 1965, US Patent 3201328 A was issued, an invention of Rees Philip Williams, for his “Continuous Fermentation Apparatus For Beer Production.” There’s no Abstract, although in the description it includes these claims:

This invention relates to the manufacture of beer, and more particularly to the fermentation of Brewers Wort, i.e. wort plus yeast as well known in the art, under steady rate conditions.

Hitherto, the fermentation process has been carried out, on a commercial scale, by batch processes which are relatively slow and involve the utilisation of relatively very bulky vessels for adequate production in quantity.

The object of the present invention is to provide apparatus suitable for use in carrying out such fermentation as a continuous process, with the advantages of relatively smaller vessels and higher production rate.

Fermentation of wort by yeast, in the production of beer, may be carried out by a continuous process including a first step of forming a mixture of sterile wort and yeast in first vessel means under temperature conditions selected to ensure multiplication of the yeast, a second step of continuously removing wort and yeast mixture which has dwelt in the first vessel means for a predetermined period of time and passing said removed mixture through second vessel means at a rate and under temperature conditions selected to ensure rapid fermentation by the yeast and production of a yeast crop, and a third step of continuously removing wort which has dwelt in the second vessel means for a predetermined period of time and passing said wort through third vessel means at a rate permitting settling.

According to the present invention, apparatus suitable for use in carrying out the above-described method, but not limited thereto, comprises a first vessel for making a ferment mixture such as sterile wort and yeast, means for controlling the temperature of the mixture in the first vessel, a second vessel having an inlet and an outlet, the inlet being connected to the outlet of the first vessel, means for controlling the temperture of mixture in the second vessel, a third vessel having an inlet and an outlet, the inlet being connected to the outlet of the second vessel, and means for controlling the temperature of fermented liquid in the third vessel.

The second vessel means could be simply a single vessel in which substantially the whole of the vigorous fermentation took place, but it is preferred to constitute the second vessel means by two vessels through which the mixture passes in succession, whereby the second method step referred to above itself includes two successive stages the first of which is a continuous passage of the mixture through a vessel at a rate and under conditions of temperature ensuring rapid fermentation, and the second of which is passage of the product through a further vessel at a rate and under conditions of temperature ensuring continuation of the rapid fermentation and a climax of the yeast crop production.

According to the type and characteristics of the beer to be produced, and of the wort and yeast to be used in the process, it is desirable to be able, at will, to both speed up and slow down the rate of fermentation. For

this purpose, gas or a mixture of gases may be introduced in the first and/or the second vessel means according to the effect sought. For example, air or pure oxygen may be introduced to boost the fermentation action, i.e. to rouse the yeast, and carbon dioxide or nitrogen may be introduced to slow down the fermentation process.

During the latter part of the active fermentation phase a yeast head is produced, e.g. in the second vessel means (and in the second of the two individual vessels where two in series are used). This head my be continuously removed together with a small content of wort, this wort being separated and recirculated, e.g. introduced back into the flow path for example immediately after the second vessel means.

It is preferred to arrange the apparatus so that the entire flow occurs by gravity through vessels arranged in series at progressively lower levels.

In a preferred embodiment, the second vessel is in two parts which are connected serially and are each provided with their individual means for controlling the temperature of the mixture therein. It is further preferred to have the temperature controlling means acting independently at separate levels, e.g. by two or more fluid jackets arranged along the vessels wall.

Preferably also, each vessel is provided with means, such as a simple conduit connected to a pump or pressure source, for the introduction of gas for quickening (e.g. rousing) and for slowing of the fermentation.

The first vessel, wherein multiplication of the yeast takes place, may be provided with agitator means adjacent the inlet end for assisting the flow and a stirrer adjacent the outlet end for ensuring mixing.

Where the process involves the production of a head on the fermented material, e.g. a yeast head, means are advantageously provided for continuous removal of such a head from the vessel in which it occurs, e.g. means for removal of the relatively copious head formed during the climax of fermentation in the third vessel. Means may also be included for continuously treating the removed head material by pressing it for removal of its wort content for recirculation.

In a preferred embodiment, for use in brewing of beer, the series of vessels are arranged successively at lower levels to give a flow of liquid through the apparatus by gravity, the inlet of each vessel being adjacent to the lower part of that vessel and the outlet of each vessel being adjacent the upper part of that vessel.

Where a gas or gases are given off during the process, one or more of the vessels may be provided with means for continuous removal of the gas, e.g. for continuous removal of carbon dioxide from the second vessel.

Where the process being carried out involves the formation of solid deposits, means may be provided for its continuous removal, e.g. for the removal of sludge from the bottom of the second of the two serially connected parts of the second vessel.

Carbon dioxide gas may also be injected in the third vessel for gasifying-of the liquor.

Where a relatively longer dwell time of the liquid in any vessel is desired, the cross-section of the vessel may be proportionately increased. Thus, by varying the size and cross-section of the vessels, the apparatus and process can be adjusted to suit the natural characteristics of the particular yeast which the brewer wishes to use.