The Heritage of Hops

I have been growing hops in my garden for a couple of years now. It is a beautiful, vigorous plant that grows well and easily. It is also a plant with a fascinating heritage and history. The modern hop has been developed from a wild plant as ancient as history itself. As far back as the first Century A.D. they were described as a salad plant and are believed to originate from Egypt. It is also a plant surrounded in fascinating facts and legend - here are a few interesting things that we have learned about the plant:

1. Hops are often referred to as the ‘spice of beer’.
2. Hops have been in regular use as a beer-making ingredient for approximately 1,000 years. It gives beer its distinctive flavour and aroma, acts as a natural preservative, and is a key component in foam quality.
3. A climbing vine, Hops, like cannabis (marijuana), comes from the hemp family Cannabaceae but do not offer the same psychoactive effects as cannabis. Interestingly enough, the hop plant has both male and female forms: the cones on the female plant are used in the brewing process, while male hops are used for breeding the plant.
4. Hop cones contain resins including alpha acids, beta acids and essential oils. The acid components (primarily alpha acid) contribute to the bitterness of beer, while the oils contribute to flavour and aroma.
5. Aroma hops are generally lower in alpha acid content, and have essential oils that are associated with great aroma. Bittering hops have high levels of alpha acids in particular. There are also dual-purpose hops that play for both teams.
6. Hop varietals can impart widely different flavours and aromas, depending on where, and the conditions in which it is grown. Randy Mosher, in his book TASTING BEER, says German hops are generally considered to be herbal, English hops spicy, earthy and fruity, and American hops – while widely variable – are generally more citrus, piney and resiny.
7. The so-called noble hops, traditional varieties from Europe, are: Saaz, Hallertauer Mittlefrüh, Tettnanger and Spalt. These can often be found in traditional lager beers.
8. Breweries use hops in a variety of forms, depending on their needs. This can include pelletized, liquid, dried, or wet hops.
9. Hops are added into the brewing process during the boil where the alpha acids are isomerized. Bitterness is enhanced with a longer boil, while aroma is reduced. This governs the timing of the additions of various hops throughout the boil. Other hopping techniques require the addition of hops at later points in the brewing process (i.e. dry hopping).
10. Hops generally impart bitterness ranging from 5-7 International Bittering Units (IBUs or parts per million iso-acids) for  Light Lagers, and up to 100 IBUs for an Imperial IPA. However these days, some experimental brewers are exploring extreme hopping, creating beers with 1,000s of IBUs. This is a largely theoretical exercise, because the human palate can only perceive a maximum bitterness somewhere in the range of 120 IBUs. This maximum is also related to the solubility of iso-alpha acids in beer.