banner 62. A comparison of quality: Freeze-dried versus kiln-dried Cascade hops

V. ALGAZZALI (1), M. Hodel (1), S. Garden (1); (1) John I. Haas, Yakima, WA, U.S.A. 

Poster Presentation

This study investigates freeze-drying hops (Humulus lupulus) and its effects on hop and beer quality. Cascade hops grown in Yakima, WA, were harvested from a single plot and then both freeze-dried and kiln-dried. A 5 kg proportion of the Cascade hops was freeze-dried at Oregon State University, and the remaining Cascades hops were conventionally dried in a commercial kiln. Instrumental analysis showed the freeze-dried hops contained substantially more oil than the kiln-dried hops (2.5 mL per 100 g vs. 1.6 mL per 100 g) and had a lower HSI than the kiln-dried hops (0.26 vs. 0.33). GC analysis of the hop cones indicated that the freeze-dried and kiln-dried Cascades also had differences in hop oil composition. Sensory analysis was carried out in beer to determine the flavor impact of the hop drying methods. A single malt lager was prepared as the control beer, bittered with high α extract to 20 BU. Forty liters of the lager was dry hopped with the freeze-dried Cascade hops and another forty liters was dry hopped with the kiln-dried Cascades hops; both at a level of 5.7 g per L (1.5 lb per bbl). A 14 member trained panel was capable of distinguishing the beers in triangle testing (P = 0.01, N = 14). In descriptive analysis testing, the panel scored the freeze-dried beer higher in grassy and earthy attributes, and the kiln-dried beer higher in fruity attributes. The drying method of the hops significantly impacted the aroma profile of the dry-hopped beers. Although the kiln-drying method produced hops with lower oil content and higher HSI, desirable flavor characteristics of the hops were transferred to the finished beer.

Victor Algazzali is a research and development scientist with John I. Haas in Yakima, WA. Victor joined John I. Haas in July 2014 and has focused his efforts on sensory analysis of hops and beer, hop product development, and instrumental analysis. Prior to joining John I. Haas, Victor earned his M.S. degree in food science at Oregon State University, working in Thomas Shellhammer’s lab. Victor is a hop and beer enthusiast who particularly enjoys the many attributes of a well-hopped stout.

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