S.s. Steiner, Inc.

Richard J H Wilson

Robert J Smith

Gerhard J Haas

Adam M Gimbel

Trevor R Roberts

Harald Schwarz

This invention describes natural hop products that are stable solutions of alpha-acids, as well as their preparation and their use for post-fermentation addition to beer for the purpose of improving the foam quality, as measured by foam stability and foam cling. Improvements in the stability (both physical and chemical) of the alpha-acids are described by incorporation of iso-alpha-acids and tetrahydroiso-alpha-acids as well as various brewery-acceptable co-solvents. The alpha-acids also improve the physical stability of the reduced iso-alpha-acids, including tetrahydroiso-alpha-acids.

Natural and stable solutions of alpha-acids and their use for the improvement of foam quality of beer

An improved flavoring composition and process for brewing malt beverages is disclosed. In one embodiment of the invention, the flavoring composition is formed from a high solids percent, room temperature stable, partially aqueous composition of a potassium salt of iso-&#x3b1;-acids. Such composition may be added to the wort kettle or else used as a post-fermentation additive, preferably after dilution with demineralized water. In another embodiment, the flavoring composition comprises a mixture containing reduced (rho-) iso-&#x3b1;-acids in alkali metal salts form, &#x3b2;-acids and hop oil. This latter composition is useful as a substitute for normal kettle extract, hops or hop pellets, allowing easy preparation of beer that resists formation of unpleasant, 'skunky' flavors but has otherwise similar flavor and physical properties.

Flavoring composition and process for brewing malt beverages

A process for the direct hydrogenation of hop resin acids in the absence of a liquid, organic solvent by reacting the hop resin acids with hydrogen in the presence of a noble metal catalyst at a temperature at which the resin acids are sufficiently fluid to allow easy mixing with the catalyst and suitably facilitate the hydrogenation reaction. Alternatively, the necessary fluidity may be achieved at relatively low temperature by subjecting the reactants to a high pressure of COgas such that the quantity of this gas that dissolves into the resin is sufficient to substantially reduce its viscosity, the pressure of the COgas being either less than the liquefaction pressure at temperatures below the critical temperature or less than that which would cause the density to exceed that at the critical point for temperatures above the critical temperature. A further variant allows for the hydrogenation of the resin acids as a suspension in water and is considered most appropriate for the processing of resins that are of relatively more viscous nature in circumstances where the application of a high pressure of gas may not be possible for mechanical reasons. Particularly useful applications for the process are the conversion of iso-&#x3b1;-acids to tetrahydroiso-&#x3b1;-acids and rho-iso-&#x3b1;-acids into hexahydroiso-&#x3b1;-acids. The resinous products of the hydrogenation process may be readily converted to aqueous, alkaline solutions suitable for use in brewing beer. The process may also be worked in a continuous manner, wherein hop resin acids in suitably fluid state and under high pressure are contacted with hydrogen gas and the resultant mixture passed over a bed of noble metal catalyst particles. The necessary fluidity is achieved either by heating the hop resin acid or by dissolving COgas into it or a combination of both. The resinous product of the hydrogenation reaction is collected by depressurization of the fluid exiting the catalyst bed, conveniently causing release of any excess dissolved gas.

Process for the hydrogenation of hop resin acids

The alkali metal salts form of &#x3b2;-acids dissolved in propylene glycol is used to control microbial growth in food products, process streams and other applications, including in cosmetic formulations.

Application for hop acids as anti-microbial agents

A process for the direct hydrogenation of hop resin acids in the absence of a liquid, organic solvent by reacting the hop resin acids which hydrogen in the presence of a noble metal catalyst at a temperature at which the resin acids are sufficiently fluid to allow easy mixing with the catalyst and suitably facilitate the hydrogenation reaction. Alternatively, the necessary fluidity may be achieved at relatively low temperature by subjecting the reactants to a high pressure of COgas such that the quantity of this gas that dissolves into the resin is sufficient to substantially reduce its viscosity. Particularly useful applications for the process are the conversion is iso-&#x3b1;-acids to tetrahydroiso-&#x3b1;-acids and rho-iso-&#x3b1;-acids into hexahydroiso-&#x3b1;-acids. The resinous products of the hydrogenation process may be readily converted to aqueous, alkaline solutions suitable for use in brewing beer. The process may also be worked in a continuous manner, wherein hop resin acids in suitably fluid state and under high pressure are contacted with hydrogen gas and the resultant mixture passed over a bed of noble metal catalyst particles. The necessary fluidity is achieved either by heating the hop resin acid or by dissolving COgas into it or a combination of both. The resinous product of the hydrogenation reaction is collected by depressurisation of the fluid exiting the catalyst bed, conveniently causing release of any excess dissolved gas.

An improved flavoring composition and process for brewing malt beverages is disclosed. In one embodiment of the invention, the flavoring composition is formed from a high solids percent, room temperature stable, partially aqueous composition of a potassium salt of iso-&#x3b1;-acids. Such composition may be added to the wort kettle or else used as a post-fermentation additive, preferably after dilution with demineralized water. In another embodiment, the flavoring composition comprises a mixture containing reduced (rho-) iso-&#x3b1;-acids in alkali metal salts form, &#x3b2;-acids and hop oil. This latter composition is useful as a substitute for normal kettle extract, hops or hop pellets, allowing easy preparation of beer that resists formation of unpleasant, 'skunk' flavors but has otherwise similar flavor and physical properties.

Iso-&#x3b1;-acids and reduced iso-&#x3b1;-acids in their free acids states are converted into mobile resins by the addition of concentrated solutions of alkali metal hydroxides. The products may be used in brewing for the bittering of beer and are most effectively used in an apparatus that automatically blends the product with water and injects the resultant, aqueous solution into beer.

Bittering of beer

Iso-&agr;-acids and reduced iso-&agr;-acids in their free acids states are converted into mobile resins by the addition of concentrated solutions of alkali metal hydroxides. The products may be used in brewing for the bittering of beer and are most effectively used in an apparatus that automatically blends the product with water and injects the resultant, aqueous solution into beer.

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Copthorne, United Kingdom

Richard J H Wilson