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Hops Oils & Aroma: Uncharted Waters

Researchers recently have begun to unravel the mystery of hops aroma, but many unknowns remain.

Stan Hieronymus Mar 16, 2016 - 11 min read

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First, the bad news. Although both Citra hops and coriander contain significant amounts of the essential oils geraniol and linalool, substituting coriander for Citra hops in an India pale ale recipe will not produce an award-winning IPA. There’s good news to come, but first, let’s dig into a few basics.

Hops Oils 101

A hops cone contains 40 to 50 percent cellulose, 15 percent protein, and 10 percent water, but it is the alpha acids (from 2 percent to occasionally 20-plus percent) and essential oils (as little as a half a percent) that interest brewers. Isomerized, alpha acids provide bitterness; volatilized, the compounds in essential oils contribute to—and sometimes dominate—aroma and flavor.

The composition of oils varies based first on the hops variety, then on multiple other factors, but most of the compounds (50 to 80 percent) will be hydrocarbons (from 20 to 50 percent oxygenated hydrocarbons) and less than 1 percent sulfur compounds.

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