Miller Brewing Company

Millercoors LLC

Jay R Refling

Henry Goldstein

Patrick L Ting

Michael A VanSanford

David S Ryder

Aki A Murakami

John R Seabrooks

Disclosed are methods for the production of light stable hop products, useful for the brewing of beer or ale to be stored in clear or green glass containers, which beer or ale will not develop objectionable flavor as a result of exposure to light. Light stable hop products are prepared by double extraction of liquid/supercritical COextracted hop solids with ethanol to remove alpha/iso-alpha-acids. Such alpha/iso-alpha-acids may be further removed from the ethanol extraction filtrate obtained in the double extraction process by subjecting such filtrate to an ion exchange medium, or precipitation by a metal ion, heavy metal ion, or alkali metal ion, or hydrogenation to provide an alpha/iso-alpha-acids free filtrate which may be added to the light stable double extracted hop solid residues obtained in the initial double extraction process.

Preparation of light stable hop products

Disclosed are methods for the production of light stable hops, useful for the brewing of beer or ale to be stored in clear or green glass containers, which beer or ale will not develop objectionable flavor as a result of exposure to light. Light stable hops are prepared by double extraction of liquid/supercritical COextracted hop solids with ethanol to remove alpha/iso-alpha-acids. Such alpha/iso-alpha-acids may be further removed from the ethanol extraction liquor obtained in the double extraction process by subjecting such liquor to an ion exchange medium, or precipitation by a metal ion, heavy metal ion, or alkali metal ion, to provide an alpha/iso-alpha-acid is free extraction liquor which may be added to the light stable hops residue obtained in the initial double extraction process.

Preparation of light stable hops

Carbon dioxide is used as a reaction solvent in the hydrogenation of organic compounds. The carbon dioxide is preferably a liquid or a supercritical fluid. The hydrogenation method can be used advantageously in methods for making tetrahydroiso-alpha-acids from alpha-acids, iso-alpha-acids, or beta-acids. If beta-acids are used to make tetrahydroiso-alpha-acids, an acidic lower alcohol is preferably added to the carbon dioxide reaction medium to act as a promoter.

Hydrogenation of hop soft resins using CO.sub.2

Unsaturated organic compounds, in particular .alpha.-acids and .beta.-acids, are purified prior to hydrogenation by mixing them with an adsorbent capable of adsorbing catalyst poisons, preferably activated carbon, and separating the adsorbent containing the catalyst poisons to recover the thus purified unsaturated organic compounds. A significant reduction in the use of hydrogenation catalyst is realized.

Purification of .alpha.-acids and .beta.-acids

Tetrahydroiso-.alpha.-acids are prepared from iso-.alpha.-acids metal salts by hydrogenating the salts in a reaction solvent of a lower alkanol containing about 5% to about 20% w/w water and in the presence of up to about 5-50 psig hydrogen and a hydrogenation catalyst at about 30.degree.-50.degree. C. to form tetrahydroiso-.alpha.-acids.

Growing community of inventors

Milwaukee, WI, United States of America

Jay R Refling