Chemical properties of the naturally dried hop plant and it's influence on the quality of beer

Abstract

In the past five years we have been monitoring the chemical composition of two hop cultivars Aurora and Bobek, harvested during the time of technical maturity and naturally dried on the hop plant in the hop garden. The hop was harvested at the end of November or at the beginning of December. The influence of chemical changes on hop resins, the quantity of essential oil and the composition of the oils was measured in beer, brewed in the pilot brewery. The results show that late harvest of so-called 'Ice Hop' affects the colour of wort and beer (more intense), the content of polyphenols and anthocyanogenes is reduced and the utilisation of alpha acids is better. It also affects the sensory estimates of beer.