Because we are celebrating National IPA Day, let’s talk a little about hops…
Ahh, hops. The mystical, magical ingredient, you find only in beer. Think about it. You’ll find any herb, spice, plant, animal in a variety of foods, but the hop plant, Humulus Lupulus, today is found in one product only. Beer.
It wasn’t always that way for beer. Prior to the use of hops, it was common to use a combination of herbs and other local plants and animal products as an addition to beer in order to provide balance, flavoring to the beer. This mixed bag of flavoring agents was called gruit. It wasn’t until the 16th century that hops became the primary flavoring additive to beer. What came about through discovery, trial and error was that beer that used more hops did not spoil as quickly, and the appearance and flavor of the beer improved. The acids in the hops are a natural preservative and the oils give aromas and flavors that are favorable and also help promote foam stability. Using this ingredient, meant the beer lasted longer in storage, has a cleaner, more complex taste and longer lasting aroma. All good things for a beer.
Hop cultivation has traditionally been within the specific latitudes of 35-50 degrees north. These latitudes also intersect the major barley growing regions.( Coincidence or fate?) The part of the plant that is used for making beer is the cone of the female plant. Some people call it a flower, but technically that is incorrect. It is a cone which is structurally similar to a pine cone. Hops are a perennial that produces annual vines from a permanent rootstock, climbing clockwise up a trellis almost 30 feet in a single season. Hops are picked at the peak of their maturity to maximize their resin content. They are dried and then shipped for immediate use or processed into pellet form or extracted into oils to be used in brewing.
Does that “skunky” flavor come from hops?
Well, if you get a skunky flavor in beer (aside from a famous Mexican lager which you dose with a lime to cover it up), something has gone wrong. But yes, it does come from the hops. That “skunk” aroma will be found in a beer in a clear glass bottle which gets exposed to light. This causes a chemical reaction in the hops that create a chemical we recognize as being “skunky”. Beer that is packaged in kegs, cans, or in dark glass bottles that block out UV rays, will not get skunky.
The wide range of flavors you get from hops comes from the various hops varieties that are grown around the world. Just like different varietals of grapes produce different wines, the different varieties of hops will add different flavors to the beer. The use of hops can be broken down to these three contributions. Bittering, flavoring and aroma. Bittering from hops come from the alpha-acids present in the hop resin. As the hop is boiled, acids are dissolved into the liquid. The longer the hop is boiled, the more bittering agents are released. Hops which are not boiled as long, release oils that provide flavor and aroma. Hops which have the shortest time in the boil, or are added later in the finishing process (dry-hopping), only provide aroma. Different hop varieties will have characteristics / flavors that can be expected based on the alpha-acid content and the concentration of the oils present at harvest.
The range of flavors you can get from hops, depending on the variety, will be earthy, spicy, floral generally for the European and English varieties. The American varieties create flavors that are have citrus or pine-like flavors. So this is part of the reason why a German lager will taste different than an English ale or an American Pale Ale.
Hops play a big role in determining a style of a beer, but are only a small portion of the recipe. You may have hundreds of pounds of barley, but may only have a few pounds of hops in any given batch. Think of it as the “spice” that gives beer life.
-John Gestautas, Keg Keeper
Master Brewers Association of America Beer Steward