Guide to Hops
As defined in Lee's Brewery Glossary page, a hop is vine whose flowers are used as a bittering agent in beer. Hops also contribute to the beer's aroma and can even increase the beer's shelf life.
Hops can be purchased in four forms; leaf, pellet, plug and extract. Lee's Brewery preferred hop form is the pellet. (Look left for a photo of hop pellets.) Pellets are easier to handle as well as weigh than leaf hops. Hop plugs are also easy to handle, but their standard 1 ounce size makes them impractical for small recipe additions. Both pellet and plug hops store much better than leaf. Of course if you're dry hopping your beer, then you must use leaf hops. (As an alternative to dry hopping, try adding a "hop tea" to the secondary fermenter.) Lee's brewery has yet to use hop extracts in its beer. Hop extracts are expensive and seem, well, just plain unnatural.
Hops come in many varieties, some of the more popular include Saaz, Hallertau, Cluster, Cascade, Fuggles, Kent Goldings and Tettnanger. Each hop variety will have its own range of alpha acid percentage or AA% (Alpha acid is a resin contained in the hop plant that is responsible for the bitterness in beer.) as well as aroma characteristics. When you purchase hops, their packaging will display the hop's AA%. This percentage of alpha acid is an important value that determines how much bitterness will be added to the beer. It is important to note that even within the same hop variety the AA% will vary year to year. For instance, adding 1 ounce of Cascade hops to a beer will not necessarily produce the same bitterness in a beer year after because of differing AA%.
In order to obtain consistent beer bitterness from year to year, a measurement called Alpha Acid Unit, or AAU, was established. (AAU is also sometime called Home-brew Bittering Unit or HBU) Where 1 AAU = (AA%) X (hop weight in ounces). This assumes a 5 gallon batch of beer. Use the JAVA Beer calculator in the Beer Math page to convert from AAU to hop ounces and from hops ounces to AAU.
Besides bitterness, hops contribute to a beer's aroma. Usually a hop cannot be a good contributor to both bitterness and aroma. In fact hop varieties generally fall into one of two categories, "bittering" or "aroma" hops. A bittering hop will have a high AA% (good for bittering) but may not be aromatic. Conversely, lower AA% hops are generally more aromatic but are not significant contributors to overall bitterness.
Hops are added at different times during the wort boil depending upon their intended contribution to the beer. Bittering hops are added early in the boil, from 60-30 minutes before the end of the boil. The alpha acids in the hops will take 60 minutes to fully break down into the wort. While aroma hops are added between 15 and 2 minutes before the end of the boil. Boiling aroma hops too long will "boil out" their aromatic contributions to the beer.
For the ultimate in hop aroma in your beer, try dry hopping. To dry hop, place 2 ounces of aroma leaf hops into a hop bag and let it float in your secondary fermenter. As a more sanitary alternative, add a hop tea to you secondary fermenter. A hop tea is made by boiling a pint of water with 2 ounces of pelletized aroma hops, then adding it, cooled and strained, to the secondary fermenter.
Revised: Friday, May 22, 1998 17:27:09
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