Hops in Scotland - A Rough Guide

The increasing interest in craft brewing and the development of premium beers has led to a growing interest in the provenance of raw materials, with a desire by many brewers to focus on locally-grown high-quality ingredients. Whilst barley from Scotland is relatively easily sourced, there has until recently been little interest in growing hops here due to the perceived climatic problems, although historically hops were grown in Scotland on a small scale up to the mid-19th century. In order to investigate the potential opportunities for growing hops in Scotland, a small trial was established at the James Hutton Institute in 2014, using protected cropping techniques. This guide is based on the outcomes and information gained from the trial. INTRODUCTION 1 HOPS IN BREWING Hops (Humulus lupulus L.) are perennial plants that grow vigorously during the warmer months, with the crop harvested in September/October before the shoots are cut back to the rootstock during the autumn after harvest. Hops are dioecious (ie. with male and female plants), and cones are formed on female plants. The formation of cones does not require the presence of male plants to produce pollen, and therefore only female plants are grown commercially in the UK. The hop plant produces stems called bines, with abrasive hairs that enable them to climb up support strings or nets. The desirable compounds in brewing come from the lupulin glands with the hop cones ( 1 ). These contain the α-acids that confer bitterness to the beer produced, and also a complex mixture of volatile oils that vary in composition between varieties. Both the α-acids and the volatiles are key to the quality of the eventual brew, depending on the hop additions in the brewing process. 1 Cone showing lupulin glands