CA1093484A

CA1093484A - Fermentation process

Info

Publication number: CA1093484A
Application number: CA314,811A
Authority: CA
Inventors: George E.A. Van Gheluwe; Finn B. Knudsen; Robert L. Weaver; Miroslav Dadic
Original assignee: Molson Companies Ltd
Current assignee: Molson Breweries of Canada Ltd
Priority date: 1978-10-30
Filing date: 1978-10-30
Publication date: 1981-01-13
Also published as: GB2032953B; DK457379A; FR2440401B1; MX5825E; BE874493A; SE440365B; SE7905086L; GB2032953A; DE2932572A1; FR2440401A1

Abstract

Case 53 ABSTRACT OF THE DISCLOSURE

The fermentation time for wort is reduced as much as 25-50% by adding an anti-foaming agent to the wort during fer-mentation to control the foam level, the anti-foaming agent being an ethanolic extract of ground malt; and continuously vibrating the wort to promote the escape of carbon dioxide.

Description

10~33~184 This invention relates to a fermentation process and in particular to an accelerated fermentation process utilizing an anti-foaming agent and vibration.
Applicant's copending Canadian patent application Serial A No. 31~, ~/æ , filed October ~t~ 1978 discloses a process for pro--ducing a novel anti-foaming agent by the ethanolic extraction of a gr~und malt.
The effect of foaming or fermentation processes are well known. There are presently available many anti-foaming agents and methods such as, for example that disclosed by U.S. Patent No.
5, ~t ~,085,70~, which issued to I.G. Farbenindustrie AG on June 29, 1937. The I.G. Farbenindustrie patent discloses a method of com-bating foam during fermentation using a liquid mixture of a solid alcohol (more than 12 carbon atoms) and a liquid aliphatic alcohol (at least 8 carbon atoms per molecule). U.S. Patent No. 2,762,7~0, which issued to S.E. Kulakow on September 11, 1956 discloses an anti-foam composition including sugar cane oil, an oil-soluble emulsifier, and possibly an oil-mi5cible fluidizing carrier.
U.S. Patent Nos. 3,249,515 and 3,354,050 both of which issued to K. Rungaldier et al on May 3, 1966 and November 21, 1967, respectively are of general interest because they disclose a method and an apparatus for controlling foaming by removing waste gas from a culture medium, separating entrained medium from the gas and adding an anti-foaming agent to the culture medium in accordance with the rate of separation of entrained medium. ~ow-ever, the patents do not disclose any specific anti-foaming agent.
In general, the case of anti-foaming agents reduces fer-mentation time. Applicants have found that the use of their novel anti-foaming agent and simultaneously vibrating or stirring the 3~ - 1 -..

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-~ ` 10!.:~3~4i fermenting wort substantially reduces the fermentation time, i.e.
by as much as 25 to 50~.
Thus, tlle present invention relates to a fermentation process comprising the steps of preparing a fermentation mixture;
adding an anti-foaming agent to said mixture during fermentation, said agent being an ethanolic extract of ground malt; and vibrating said mixture during fermentation to promote the escape of carbon dioxide and reduce the fermentation time.
The anti-foaming agent used in the fermentation process is produced by the extraction of ground malt with ethanol having a concentration above 75% at a temperature of 50C, as disclosed in detail in applicant's copending patent application identified here-inbefore.
The speed of fermentation is controlled by several factors, including pi`tch-iPg rate~ the q~ant~ty o~ xe~st i~ suspens~on~ t~e amount of carbon dioxide in solution and the sterol concentration.
The sterol formation is partially controlled by the presence of lipids and lipoproteins. Mo~eove~ the presence of sterol increases ester formation. The time for the fermentation of wort can be re-duced by keeping yeast in suspension and promoting the escape ofC2 by stirring or vibrating the fermenting wort. Carbon dioxide has an inhibitory effect on fermentation. An advantage of the anti-foaming agent is a dispersing action and control of the foam head, particularly during the active fermentation.
The vibrator used in the process of the present invention may be similar to those used in pouring cement. Such a vibrator is easy to operate, requires little energy input as compared to mechanical stirrers and is microbiologically acceptable.
In experiments, fermentations were carried out in an

- 2 -10~3~4 ` ;all glass "Unitank" type 25L fermenter with a vibrator mounted 2 inches from the bottom. The ethanolic extract of ground malt was used as the anti-foaming agent, and the vibrator was operated continuously from the start of the fermentation. A high gravity wort was end-fermented in 4 days. A control wort fermented under the same conditions without vibration took 6 days to reach end-fermentation. Additional experiments with the vibrator proved that low frequency vibration (below 2000 vibrations/minute) was more effective than high fre~uency vibration in promoting the }0 escape of carbon dioxide from the fermenting wort.
Experimental ale and lager fermentations carried out in pilot plant fermenters showed an average two day shorter fermen-tation cycle, a higher bitter units and no differences in foam retention of the finished beer when the fermentation is conducted with the vibrator and the anti-foaming agent.
In a commercial fermenter, upper and lower foam sensors would be used, the lower foam sensors being used to cut off the ` addition of anti-foaming agent. The anti-foaming agent is sprayed onto the surface of the fermenting wort, with one or more low frequency vibrators installed near the bottom of the fermenter.
Logically, the ant~-~fo~ng agent is added automatically when foam reaches the upper sensor.
Upon completion of the fermentation, the anti-foaming agent is separated by filtration. The anti-foaming agent added is used up, and no harm is done even if it is not used since the agent constitutes a normal constituent of beer.
At least in theory, the method of the present invention can be used in any microbiological fermentation, e.g. in the production of yeast or antibiotics.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A process for fermenting beer comprising the steps of preparing a beer-producing wort; adding an anti-foaming agent to said wort during fermentation to control the foam level, said agent being an extract of ground malt produced by extracting the ground malt with ethanol having a concentration of above 75%; and continuously vibrating said wort during fermentation.