What is Hops?

Written by George on December 23, 2015
Hops Photo credit: Paul Miller
Photo credit: Paul Miller

Hops are the female flower clusters or seed cones of the hop vine Humulus lupulus, which are used as a flavouring and preservative agent in nearly all beer made today.

Hop vines Photo credit: Bernt Rostad
Hop vines
Photo credit: Bernt Rostad
They have been used for medicinal and food flavouring purposes since ancient times; by the 7th century in Carolingian monasteries in what is now Germany, beer was being made with hops, though it isn’t until the thirteenth century that widespread cultivation for use in beer is recorded.

Before the thirteenth century, beer was flavoured with plants such as yarrow, wild rosemary,

Yarrow Photo credit: Peter O'Connor
Photo credit: Peter O’Connor

and bog myrtle, and other ingredients such as juniper berries, aniseed and ginger, which would be combined into a mixture known as gruit and used as hops are now used; between the thirteenth and the sixteenth century, during which hops took over as the dominant flavouring, beer flavoured with gruit was known as ale, while beer flavoured with hops was known as beer.

Juniper berries Photo credit: Ken Bosma
Juniper berries
Photo credit: Ken Bosma

This vine is cultivated between the 35th and 55th degree Latitudes in both the North and South Hemispheres, because they need specific summertime day lengths to trigger flowering. They are large, beautiful plants that would look amazing as ornamental plants in any garden.

However, the most prized varieties are tied to specific locations. Saaz, which happen to be my favorite, gets it’s spicy character from the orange soil of western Bohemia. The herbal Hallertau grows in a district with the same name in northern Bavaria. Similary, the East Kent Holdings grows just southeast of London.

India grows hops in the Lahaul region of Himachal Pradesh. The plants grown here are high in Alpha acids which are ideal for bittering. Unfortunately, these do not seem to have done well in the brewing industry, and all our breweries are importing hops from overseas. I understand from a recent blog post made by John Eapen at TalesOfFroth that Bira are sourcing and using Indian hops in their beers.

Inside the hop cone is a small stem that holds all the leafy parts together. All around this stem are tiny little blobs of a waxy substance called lupulin. This is what contains the aromatic oils and bitter resins that gives beer its wonderful flavours. The bitter resins are divided into Alpha and Beta acids. The alpha acids are the measure used for describing the bittering power. Alpha acid contents range from 2% up to almost 20%.

Hop cone with visible lupulins Photo credit: bizzlenj
Hop cone with visible lupulins
Photo credit: bizzlenj

The lupulin also contains numerous aromatic oils, each with its own characteristic. Every region and variety of hops has it’s own uniqueness. Aromas like floral, fruity, earthy, minty, spicy, to name a few add great personality to beer. German hops tend to be herbal, while English hops are spicy to fruity. The amazing Saaz hops has a nice distinctive spiciness. American hops are varied, but most seem to demonstrate a piney to resiny character.

Then there is a variety of hops that are referred to as “Noble”. These are typically used for aroma in Lagers. These include the Saaz, Tettnager, Spalt, and Hallertauer Mittelfruh.

In addition to aroma hops, there are very high alpha varieties that have been developed over the past 100 years. Some examples are Chinook, Columbus, Agnus, Centennial, and Apollo.

There are also dual use hops that combine moderate alpha acids with pleasant aromas.

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