Analysis and prognosis of bitter acids content in Czech hop varieties - year 2018 and long-term comparisons and trends

This article presents the results of the harvest forecast of the alpha- and beta-bitter acids of the Czech hop varieties in the 2018 harvest, the results are discussed in relation to the long-term averages, the composition of the bitter acid analogs and the stability of the varietal characteristics. 180 hop samples were analyzed using EBC 7.7 (HPLC) method. The alpha-acid content of the most important Saaz variety (2.9% in dry matter) was identical to the 2017 harvest and 18% rel. lower than the 26-year average. The alpha-acid content of Sladek (5.0%), Premiant (4.8%), and Saaz Late (1.6%) varieties was significantly lower than the long-term average. The harvest of the hops of the Kazbek and Agnus varieties was close to the long-term average. The ratio of alpha- and beta-acids, the relative content of cohumulone and the relative content of colupulone were consistent with long-term averages for the tested varieties. It was confirmed, that the harvest forecast gives timely information on the alpha-acids content of the harvest, the results were in good agreement with the values of the final evaluation of all harvested hops samples.