Chapter 3

Hops

Isomerized Hop Products

With isomerized hop products, the alpha acids have been isomerized to iso-alpha acids to improve alpha-acid utilization and minimize boil times, both of which reduces costs. As a result, they can be added to the kettle not only during wort boiling, but also-unlike non-isomerized products-during the conditioning phase. Products included in this group widely used by brewers are as follows:

Isomerized Hop Pellets

Isomerized hop pellets are basically conventional Type 90 pellets in which the alpha acids have been converted to iso-alpha acids. Isomerized pellets can be added at any stage of boiling while maintaining high utilization. Consequently, late additions of aroma hops optimize utilization of the alpha acids not usually converted with typical hop aroma late kettle additions. Isomerized pellets can be added to the kettle 15 minutes prior to knockout if the goal is to add hop flavor and aroma to the beer (30).

Isomerized Extracts

Isomerized extracts represent the most recent technology in the development of hop products. The processes for producing isomerized extracts are sophisticated chemical processes that convert the alpha acids to iso-alpha acid compounds and formulate them in concentrated form. The main advantage of using isomerized hop extracts is the significant increase in utilization that can be achieved.

Isomerized Hop Extracts

somerized hop extracts can be used as a partial replacement of kettle hops, as a means of improving utilization, or as a final adjustment of beer bitterness prior to filtration.

Isomerized Kettle Extracts

Isomerized kettle extracts contain iso-alpha acids, other soft resins (including beta acids), and essential oils. If the oils are removed prior to processing, the isomerized extract is used only for kettle bittering unless it is reconstituted (oil added back after processing), in which case it can be used for both bittering and aroma (15).

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