Patent GB-1188291-A (GB)
Title: Improvement of Beer Flavour
Inventor: HELM ERIK JOHANNES
IPC: C12C11/00
Filed: 1966-08-10
Abstract: 1,188,291. Improving the flavour of fermented beverages electrolytically. ALFRED JÏRGENSEN, LABORATORY FOR FERMENTATION Ltd. Aug. 8, 1967 [Aug.10, 1966], No.35810/66. Headings C6E and C7B. In a method of improving the flavour of fermented beverages such as beers, ciders and wines, by removing hydrogen sulphide produced during fermentation, at least part of the hydrogen sulphide is precipitated by electrolytically dissolving a small quantity of copper in the fermented beverage. The dissolution is conducted by passing the beverage continuously between two electrodes, at least one of which is of electrolytic copper, and passing a direct current of pre-selected strength through the beverage by means of the electrodes, the current strength being so selected that no harmful excess of copper over that required to precipitate all the hydrogen sulphide in the beverage passing the electrodes, is dissolved into the beverage. In the case of beer, the copper is dissolved in the beer after an accelerated maturation but prior to the final filtration, and the accelerated maturation may consist of a second fermentation at a temperature between 4‹ C. and 8‹ C. In a preferred procedure two primary fermentations are undertaken, the one (a) with a flocculent . strain of pure yeast and the other (b) with a non- flocculent strain. At the end of these two primary fermentations the yeast in A will have settled out before the attenuation is completed while B will be completely, or nearly completely, attenuated with much yeast remaining in suspension. The two fermented worts A and B are then mixed together so that the yeast carried over from B will proceed to ferment the residual unfermented sugar in A. If necessary, more non-flocculent yeast may be added to brings its concentration to a level suitable for the accelerated fermentation. An electrolytic cell for the dissolution of copper in alcoholic beverages in small quantities consists of two circular electrodes 5 machined from electrolytic copper, 16 cm. in diameter and 0À6 cm. thick with a central boss for making the electrical connexions. The electrodes 5 are held in place, with a separation of e.g. 2À5 cm., by stainless steel discs 6, from which they are insulated by rubber discs 7. The stainless steel discs 6 are held by threaded and notched rings 8, which can easily be unscrewed for cleaning and replacement of the electrodes. The entry and exit ports 9 and 10 are tapered outwards Fig. 2 (not shown) in a plane parallel to the electrodes and tapered inwards in a plane perpendicular to them in such a way as to preserve an approximately constant crosssectional area throughout the passage of the cell. The entire inner surface of the housing together with the entry and exit ports, is coated with an insulating layer of synthetic resin to prevent any of the applied current from leaking across the housing. An E.M.F. of 5 volts is applied to beer while flowing through the cell at a rate of 1 or 2 litres per second. The direction of the current is reversed at uniform intervals. Mention is made of a laboratory apparatus in which the copper electrodes are mounted against plastic washers on either side of a cell constructed of plastics material.