GB1011160A - Sequential fermentation process for the production of alcoholic cereal beverages - Google Patents

Abstract

In fermenting wort containing fermentable sugar with yeast to produce an alcoholic cereal beverage such as beer, a carbon dioxide atmosphere is established in a closed fermentation vessel, the carbon dioxide atmosphere is maintained in the vessel while a batch of wort is introduced into the vessel and the fermentable sugars in the wort are fermented to produce alcoholic beverage, while the alcoholic beverage is withdrawn from the vessel, and while the vessel is cleaned for the reception of another batch of wort, and thereafter the steps of introducing a batch of wort, fermenting the sugars and withdrawing alcoholic beverages are repeated in the presence of the carbon dioxide atmosphere on at least one other batch of wort. Sterile air or oxygen may be admitted to a filled fermentation vessel for the purpose of being dissolved in the wort to promote yeast growth, while at the same time maintaining the carbon dioxide atmosphere in the vessel. Carbon dioxide pressures in the range from about 0.1-10.0 lbs. per sq. inch gauge pressure are suitable. Two methods of operation are described in considerable detail. According to one, Figs. 1-5 (not shown), the materials in the vessel are settled upon completion of fermentation to form a yeast layer which is removed hydraulically after withdrawing the alcoholic beverage. Thus, cold water is sprayed through downwardly directed nozzles in a 10 second burst at 40 lbs. per sq. inch gauge pressure over each 3 minute cycle for a period of two hours, then the water is sprayed during similar 3 minute cycles alternately through both upwardly and downwardly directed nozzles for a further two hours, by which time yeast has been completely removed from the vessel. Next, cleaning solution is sprayed under the same condition through the upwardly directed nozzles for about 1 hour, then alternately through both the upwardly and downwardly directed nozzles for a further one-half hour period; this cleaning removes any crusty reddish-brown ring or beer stone within the vessel. Lastly, rinse water is similarly sprayed alternately through the upwardly and downwardly directed nozzles on 3 minute cycles for a one-half hour period. The cleaning solution should be acidic (such as one using phosphoric acid including sequestering and wetting agents, or sodium carbonate) rather than alkaline (sodium hydroxide or tri-sodium phosphate), since the latter will react with the carbon dioxide atmosphere. Experimental runs were made using one or more rectangular fermenting vessels 45 feet long, 9 feet 9 inches high and 10 feet 2 inches wide, wherein the floor was pitched so that it was 6 inches higher at the back of the vessel than at the front, and the attemperating coils or jackets for the vessels carried a liquid coolant such as propylene glycol, brine or ice water. In the other method, Fig. 6 (not shown), the wort and yeast are agitated during fermentation and the alcoholic beverage withdrawn from the vessel carries suspended yeast, which is subsequently separated off in a centrifuge.