HOPS HARVEST
Happy September – it is hop harvest time in the United States Pacific Northwest. Hops are huge in beer and the Pacific Northwest is the largest hop growing region in the US. The weather has been better this year for hops in Oregon and it is expected that there will be a record yield of hops. What do hops provide to beer – read on!
Hops in beer provide balance to the sweetness and toasty flavors of malt and compliment the fruity flavors produced by ale yeast. Beer can be made without hops, but it might be unrecognizable to many as even a beer.
The hop plant is a climbing vine with the Latin name of Humulus lupulus. Doesn’t that sound like a spell in “Harry Potter”. Hops can perform magic in beer due to the chemical makeup of the hop cones. The cones are the flowering part of the hop plant, and the cones contain all the good stuff of hops. Only female hop plants flower so commercial hop growers pull up the male plants. Back to the good stuff. Within the cone flower are little glands called lupulin which contain a golden yellow powder which is referred to as lupulin.
Lupulin contains the resins that provide bitterness to beer as well as the oils that provide aroma and flavor. An important resin is alpha acid. On their own, alpha acids are not bitter, but when the alpha acids are heated, they isomerize to form iso-alpha acids. Sounds like a few more spells from “Harry Potter”. Iso-alpha acids are the bittering agents in beer. When making beer, the liquid wort is boiled for an hour or more. The isomerization of alpha acids is a slow process, and hops are added to the wort at the start of the boil to get the desired bitterness of the beer. If you want a less bitter beer, add the hops later in the boil, but usually the boil including hops would not be less than 45 minutes.
What about the oils in lupulin? These oils provide flavor and aroma. There are hundreds of different oils, but all are very important in the flavor and aroma of each type of hop. Oils evaporate when boiled with the wort so to provide flavor and aroma to beer, hops must be added later in the boil. A single beer may have multiple types of hops. A hop for bitterness would be added at the start of the boil. A hop for flavor would be added about halfway through the boil, and a hop for aroma would be added near the end of the boil or even after the boil is complete.
A term that might be seen on a menu at a craft brewery is “dry hopped”. When the beer is dry hopped, hops are added to the beer after fermentation is complete. The hops become wet in the beer. At this phase in the brewing process, there is no heat so there will be no formation of iso-alpha acids (bitterness). Adding hops at this point in the process will provide extra aroma to the beer.
There are hops that have a higher level of alpha acids in the lupulin and hops with higher levels of oils. This leads to the terms bittering hops and aroma hops. All hops have both alpha acids and oils but through breeding, some have more of one compound versus another. There are hop varieties associated with locations in the world and they are known for the properties imparted to the beer.
German and Czech hops are known for their floral, perfumy, minty and peppery properties. Hallertau, Tettnang and Saaz are three well known hop varieties from this region.
United Kingdom hops are known for their herbal, earthy and green tea properties. Some well-known hops are East Kent Goldings and Fuggle.
American hops are known for big aroma and flavors including grapefruit, pine resin, tropical fruit and even catty and oniony aromas and flavors. Some well-known older American varieties include Cascade, Centennial and Chinook. Some newer varieties include Citra, Simcoe and Mosaic.
Many countries have hop breeding programs working on disease resistance, new aroma and flavor varieties and how global warming is impacting the hop crop. Hops are big business globally and the changes to climate are impacting traditional hop growing regions like Germany and the United Kingdom as well as in America in the Pacific Northwest where wildfires are a big issue. Hops are grown all over the world and the climate, soils, and water all have an impact on the hops flavor and aroma profile.
So, hooray for hops and all that they add to beer. Bitterness, flavor and aroma to match many different palates would make any witch or wizard proud. Humulus lupulus!
