Hops are the flowers of the Humulus lupulus plant, a member of the hemp family. Humulus lupulus grow on both coasts of the US, and in Europe. Hops are an essential ingredient in beer because they contain slightly to very bitter essential oils that help to give beer, ale and the like its tang. Generally beer makers strive to find the perfect blend between malt, which is sweet, and hops to provide that sweet/sour taste with which every beer drinker is familiar.
Beer making aside, hops come from an interesting plant. The plants grow in tall vines that can reach heights of 18 feet (5.49 m). The leaves of the plant are a deep verdant green, and the conical, light green flowers burst into bloom in late summer. The plants are perennial, and though they may require some trimming back, once they’re well established they come back each year.
Brewers only use the hop plant’s flowers, ignoring the leaves. Once these are harvested, they are frequently dried. Both home and commercial brewers know that hop flowers can significantly change the taste, flavor notes and aroma of beer. As microbreweries have become more popular, interest in where and how the hop plants are cultivated, grown and harvested has increased. Serious beer tasters report that hop flowers can impart numerous flavors to beer. Some have greater citrus or herb notes, while others impart a flower fragrance.
There are plenty of varieties of this flower and one of the most commonly known is the Noble. These tend to give a lot of flavor and fragrance to beer but don’t make the drink too bitter. Other hops are certainly favored too, and some are specifically used to make beer bitterer and have higher acidic contents.
Hop flowers are also useful in helping to preserve beer, and this likely became a reason for using them about 1400 years ago. The first known use of hops was in Germany in the 8th century. Britain, well known for many of its many different beers didn’t start using hops until the 15th century.
In brewing, hops may be added at different points during the brewing process to change the flavor of beer. Bitters, a type of hop, are boiled with the beer ingredients. Adding hop flowers during the later part of the boiling process will mean more aromatic beer with less bitterness. Some brewers use a process called dry hopping; they add hop flowers to the beer after it has cooled. This provides lots of aroma but keeps the beer taste relatively sweet.