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Elements of Beer: Recycling Hops in the Brewhouse

Think you need to throw out all that fragrant green sludge? Maybe you don’t. A few American brewers are experimenting with reusing spent dry hops, and the results are intriguing.

Stan Hieronymus Apr 24, 2020 - 11 min read

Elements of Beer: Recycling Hops in the Brewhouse Primary Image

Paul Farnsworth was 16 years old when he began working as an apprentice at Truman, Hanbury & Buxton’s brewery in Burton-upon-Trent. By the time he got his Ph.D. from the University of London in 1973, one of the tasks he had performed was calculating how much bitterness could be obtained by boiling hop cones that had already been used in the hop back.

He arrived in the United States in 1976, and ever since he has watched American brewers use hops less and less frugally. Along with teaching at various universities, he built and equipped 50 breweries and fermentation plants around the world, set up quality-control programs for dozens of small breweries, taught brewing, and occasionally brewed himself. Officially retired, he still consults with breweries that interest him.

“The United States changed dry hopping,” he says. At Truman, he was part of a three-man team that dry hopped individual casks, adding Goldings at a rate comparable to six ounces per U.S. barrel. Today there are brewers using more than 15 times that amount. Almost always, the hops are discarded after a single use, although research at Oregon State University recently revealed that they are still rich in compounds brewers covet.

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