We're all familiar with the fact that hops are found in our beer. Many of us even prefer "highly hopped" brews. If you have paid attention at all to the beverages you're consuming, then you know that hops are an integral part of the brewing process and have probably at least heard of noble hops. What are they, though? Let's take a closer look at the four noble varieties and what makes them "noble."
All hops are climbing plants that are trained to grow up lattices or other upright structures so that they can be harvested more easily and to help maximize plant growth. Hops are grown around the world, and there are some notable varieties found in many different nations. However, the four types that are referred to as noble come from central Europe. You'll find Tettnanger, Hallertauer Mittlefrueh, Saaz and Spalter. Each of these is low in acid, but high in aroma.
No one knows how the term "noble" became applied here, though some speculate that it has to do with the traditional use of these varieties in many European styles. For instance, you'll find that these hops are required to create several popular types of beer – pilsner, marzen and dunkel, for instance.
Noble hops are prized for their aroma and are usually used in dry hopping, though smaller brewers often used them throughout the brewing process. They contain 2 to 7% AAU of alpha acid, and generally have a clean aroma. Interestingly, the name only applies when the hops are grown in their native region – the town or area where they were traditionally grown throughout history.
As a side note, the supply of these additives is declining. Pests are taking their toll on harvests, but there is also increased pressure in terms of arable land. In order to increase the yield offered, some growers are turning to hybridization – Mt. Hood and Liberty are both hybrid varieties that combine noble hops with US types. The result is a higher-acid additive that still offers a good, clean aroma, though it is not quite the same as the original variety.
Another interesting development here is the fact that many smaller brewers are eschewing the use of these additives in favor of other options. To achieve different flavors and aromas, many are using hops grown in the US, or are turning to Kent or Goldings hops. The result is a unique fusion of aroma and character that enhances the current craft beer industry.