The term Noble Hops referrs to four low-acid, high aroma varieties that orignated in central
Europe. These are : Tettnanger, Hallertauer Mittelfrueh, Spalter, and Saaz. Their particular
aromatic properties are the backbone for the traditional aroma and flavor of many classic styles
including Pilsener, Dunkel, and Oktoberfest/Märzen.
While the origins of the phrase "Noble Hops" is not known, it is likely that these varieties where termed this way due to their long history of use that has defined many classic and wonderful European styles and brands.
Like wine grapes, hops take on the various characteristics imparted by their geographic growing regions. This is known in winemaking as 'terroir' - a term which could rightly be applied for these hop classifications. For official purposes, the term "Noble hops" can only be applied to these four varieties when they where grown in their original location. For example, Tettnanger originated a small town in southern Baden-Württemberg Germany called Tettnang.
You may hear the English Fuggle and East Kent Golding referred to as Noble Hops. They share many characteristics with the four 'true' Noble Hops, and are the backbone of several longstanding beer styles. However, technically speaking, they are not truly Noble Hops.
Due to the pressures of land usage in their native growing region, as well as various hopyard pests, the supply of true Noble Hops is decreasing. Growers have responded by producing hybrid varities such as the Liberty hop, which is mating of Hallertauer Mittlefruh with a disease-resistant US cultivar. Mt. Hood is another example of a higher acid hop (5 to 8%) hybrid.
Typical Use : Usually Aroma/Dry Hopping, but certainly in smaller AAA beers for all stages
Alpha Acid : about 2 to 7% AAU
Origination : Europe
Commercial Examples : Pilsner Urquell, various Hefeweizens, lots of European, classic beers.
Characteristics : Clean, Flowery, "Refined"
Styles : Pilsener, Dunkel, Oktoberfest/Märzen, Weizen, some Belgians, and many other classic European styles.