Cascade
Very successful and well-established American aroma hop developed by Oregon State University's breeding program in 1956 from Fuggle and Serebrianker (a Russian variety), but not released for cultivation until 1972. It has a flowery and spicy, citrus-like quality with a slight grapefruit characteristic. One of the "Three Cs" along with Centennial and Columbus. Substitutes: Centennial and Columbus (but they have a higher Alpha Acid content).
Centennial
American aroma-type variety bred in 1974 and released in September 1990 by S.T. Kenny and C.E. Zimmermann, the breeders of this variety. Similar to Cascade and Chinook. The genetic composition is 3/4 Brewers Gold, 3/32 Fuggle, 1/6 East kent Golding, 1/32 Bavarian and 1/16 Unknown. One of the "Three Cs" along with Cascade and Columbus. Centennial is often referred to as a 'Super Cascade', since it has a strong citrus aroma.
Chinook
This green bine cultivar (W-421-38) was released in May 1985 in Washington State and Idaho from a cross between a Petham Golding and a USDA-selected male (63012M). Slightly spicy and very piney. Its alpha acid content ranges from 12 to 14%.
Citra
Citra Brand is a registered trademark used with HBC 394 cv special aroma hop variety developed by the Hop Breeding Company (a joint venture between John I. Haas, Inc. and Select Botanicals Group, LLC). It was released in 2007. Citra Brand hops have fairly high alpha acids and total oil contents with a low percentage of cohumulone content. Citra Brand hops imparts interesting citrus and tropical fruit characters to beer.