Hops, with their brash attitude, inspire legend.
Hops contain two types of acid known as alpha and beta acids, which both act as natural preserving agents by killing or hindering the growth of various bacteria. British brewers took advantage of this by brewing intensely-hopped beers (which eventually became known as India Pale Ale, or IPA) in order to prevent spoilage on their long journey to British colonies in India. Hops become a component of British beer in the 16th Century, and it was another century until hops appeared in the states.
The hop is a climbing plant related to hemp, and there are both males and females. Hops grow on trellises that are usually 18 feet tall. The Cannabaceae family has two genera: Cannabis and introducing Humulus, better known as hops. Only the female produces the flowers that are used for brewing.
Alpha Acids - Found in the resin glands of the flowers of the hop plant. When isomerized by boiling, give bitterness to beer.
International Bittering Units (IBU) – A chemical measurement of the actual bitterness in beer. An IBU is defined as one milligram of isomerized alpha acid per liter of beer.
Lupulin Glands – Bright yellow nodes at the hop petal base that contains alpha acids and essential oils.
Bittering hops usually have a high alpha acid content. Aroma hops, with low-to-medium alpha levels, mainly impart characteristic hop aromas to beer.
At the base of each petal are lupulins, glands that contains alpha acids that give beer this bittering aroma and flavor. As their name implies, bittering hop varieties are those that impart bitter flavor to beer and have high alpha acid levels. They typically have a high alpha acid content. Aroma hops, with low-to-medium alpha levels, mainly impart characteristic hop aromas to beer.
The largest producers of hops are Bavarian Germany, the United States, China, and the Czech Republic. Other important growing regions include England, New Zealand, Australia and Poland. Most of the hops used in the United States are grown in the Oregon/Washington region. Hop plants sprout in the spring, are harvested in Fall, starting in August and continuing into October. After harvested, they can be used as is but are typically dryed for long term storage.
Whole-leaf hops: During harvest, whole dried hop cones are removed from the plants, dried and compressed into bales. Leaf hops are believed to have greater aromatic qualities and are often used after fermentation in dry hopping. To increase hop aroma, leaf hop additions can be made at end of boil to capture more of the volatile oil. Because the leaf can soak up work, you will likely have a loss in volume and they can clog the kettle or wort chiller. Using whole leaf hops can impart a more complex hop profile and flavors.
Pellets: Dried cones are shredded, compressed, and extruded into pellets that retain all of its lupulin ingredients. They are typically the craft beer industry standard, because of the advantages in measuring, storage and shelf life. They stay fresher longer, because they have less surface area to oxidize. There’s also higher extraction due to more exposable surface area. However, because their composition is altered, they tend to lose some of their aromatic quality.
Varieties of hops are chosen for the properties of bitterness, flavor, or bouquet.
Hop varieties are chosen for the properties of bitterness, flavor, or bouquet that they lend to the beer and help to balance the sweetness of malt sugars. Beer would be annoyingly sweet without it.
American Hops: American hop varieties are high in citrus, grapefruit, piney, resinous and fruity notes. Cascade, Centennial, Chinook, Willamette and Amarillo are among the most widely used American-style hops. Here’s just several:
- Cascade: One of the most popular varieties, it has a moderate bitterness level and a fragrant, flowery aroma. It’s typically used in West Coast ales. The iconic Sierra Nevada Pale Ale propelled the Cascade hop. Other notable cascade beers include Deschutes Brewery, Mirror Pond Pale Ale and Anchor Brewing, Liberty IPA.
- Chinook: With a high 11-13% acid range, Chinook has distinctive pine and spicy flavors. The alluring pine forest and grapefruit aroma makes it a popular variety for hopping many beer styles including American-style Pale Ales.
- Amarillo: Used primarily for aroma, these medium bittering hops hale from Washington. They give off unique flowery, citrus notes and are commonly used in American IPAs, American Ales and wheat beers. To taste what a single-hop Amarillo beer tastes like, pick up a Rogue’s Yellow Snow IPA or Mikkeller Single Hop Amarillo IPA.
- Centennial: A relatively new hop on the market, Centennial is responsible for highly-hopped pale ales and IPAs. Notable Centennial beers include Bell’s Brewery, Two Hearted Ale and Flying Dog Brewery, Centennial Single Hop Imperial IPA.
- Citra: The widely popular and aromatic hop resulted from a cross-breed of several varieties from the UK, Germany and the U.S. After Sierra Nevada introduced Citra in 2009 in its Torpedo IPA, it quickly became one of the beer world’s most sought after hops. Imparting an unusual mix of passion fruit, tropical fruit and citrus flavors, it’s become one of the trendiest and elite hops to use in beers such as Three Floyds Zombie Dust and Kern River Citra.
Since 2007, there’s been talk and speculation about hop shortages. The craft beer revolution, debilitating drought and the infatuation with IPAs and DIPAs (relying on more temperamental aromatic hops) have made many of these hop varieties more scare in the U.S.
Craft brewers use roughly six times more hops than beers produced by large corporate brewers and craft beer now claims 8% of the US beer market.
According to Esquire, there’s been an increase by as much as 2 million pounds of the precious flower from 2012 to 2013. With the price of hops doubling in the US over the last 10 years, it is likely one of the reasons we’re seeing more ‘single-hop’ craft beers.
As Boston Beer President Jim Koch once stated, “hops are to beer what grapes are to wine.”
Tests done on hop oils have found over 400 different compounds in hop oils with more being found all the time. That’s a lot of flavor potential. With this dynamic range of flavors and aroma from potent citrus to resinous pine, hops not only put the bitter in beer, but the character in the craft.