Comparison of phytochemical and brewing characteristics of Cascade and Kazbek hop cultivars

Abstract

A four-year study compared the secondary metabolite profile of two flavour hops, the widely used Cascade and the new Czech variety Kazbek. The average alpha-acids and total essential oil of Kazbek and Cascade grown in Europe did not differ, while alpha-acids were 20 % higher in Cascade grown in the USA. Cluster analysis of essential oil composition distinguished the varieties, the markers being mainly farnesene derivatives. US-Cascade had higher terpenoids (geraniol, geranial) and lower fatty acid methyl esters than EU-Cascade. Both varieties have high and comparable levels of geraniol esters (230–360 mg/kg total) and low levels of free geraniol. The sulphur-containing volatile profile of US-Cascade and EU-Cascade hops differed significantly, probably as a result of treatment with different pesticides. The profile of hop-associated essential oils and aroma components of the single-variety experimental beers Kazbek and Cascade was similar for both whirlpool-hopped and additionally dry-hopped beers. Citrus and fruit notes were the dominant descriptors. Two independent sensory panels did not clearly distinguish or prefer beers hopped with Cascade and Kazbek hops, demonstrating the possibility of alternating between the two varieties in brewing. A new finding is that genetically distant hop varieties can provide similar sensory profiles in late- and dry-hopped beers.