A Comparison of Hop Drying with Unheated, Dehumidified Air Versus Traditional Drying with Heated Air

MBAA TQ https://doi.org/10.1094/TQ-55-3-1108-01 | VIEW ARTICLE
Val Peacock (1), Bill Arendt (2), Randy Thiel (3), Matt Gura (4), and Luke Chadwick (5). 1. Hop Solutions Inc., Edwardsville, IL, U.S.A. 2. Arendt’s Hop Haven, Nekoosa, WI, U.S.A. 3. New Glarus Brewing Co., New Glarus, WI, U.S.A. 4. Hop Head Farms, Hickory Corners, MI, U.S.A. 5. Bell’s Brewery Inc., Galesburg, MI, U.S.A.
The traditional hop drying method in the United States is to pile them 24–32 inches deep in a large box and force 120–150°F heated air through the bed. The result is uneven drying, even under the best circumstances, with the bottom hops at about 5% moisture and the hops at the top at 15–20% moisture. The process is hard to control and can result in quality problems, including fire danger. Overheating the hops often results in the formation of an undesirable onion/garlic aroma, which can be avoided by not heating the hops. Drying a 24–30 inch deep bed of hops with unheated, dehumidified air results in a less than 1% moisture difference between the top and bottom of the bed, and the process is easy to control. Traditional hop drying is extremely energy intensive, and it was hoped that drying with unheated, dehumidified air would reduce energy use. The system studied uses an almost identical amount of energy per pound of hops, but the system could probably be optimized to reduce this. The disadvantage of drying with dehumidified air is that it requires 24–48 h versus 5–13 h for traditional drying.


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