The following notes are meant to help readers get the most out of the information contained in the data sheets. The following items describe the properties of hops:
These are brief remarks about the ancestry of a variety. In the case of very old varieties like Saaz or Hallertau, there is no ancestral information, we know only that this particular varietal type was selected over many years by growers and brewers in that particular area. More modern varieties can often be traced back through two to three generations of crosses often involving other known hop varieties. It is important to note that the qualities of a hop variety are only partly determined by the genes it receives--of at least equal importance is the selection for particular characteristics practiced by the hop breeders.
This is a statement of the time in the hop harvest season at which the particular variety reaches optimal maturity. Harvesting in this country occurs from about August 20 to September 20. Of current U.S. varieties, the aromatic types tend to be earlier maturing than the bitter type hops.
This is the kiln dry weight of hops normally produced by that variety in commercial production in the U.S. On average the aromatic types tend to be lower yielding and hence more highly priced than the bitter types. As with other crops, yields vary markedly from farm to farm and year to year. Hence, the range in yields can be quite wide.
Hop varieties vary widely in structural aspects such as general vigor, lateral (or side-arm) length, and the overall vine structure. These characteristics can make a variety more or less easy to pick and handle.
Different varieties can display a wide range of reaction to various hop diseases. Of great importance in this country are the fungal disease downy mildew (caused by Pseudoperonospora humuli ) and the viral disease ring-spot (caused by Prunus necrotic ring-spot virus). Clusters and Galena are rather sensitive to downy mildew infection whilst Cascades and Tettnang rarely exhibit disease symptoms. Galena, when infected with ring-spot virus, shows extreme symptoms under changeable climatic conditions. Certain interesting responses to pests also occur. Nugget, for example, is very sensitive to two-spotted mite attack ( Tetranychus urticae ).
This is another characteristic which is of direct concern to both grower and brewer. If a hop is known to pick well, one can expect a good clean sample. If a hop is difficult to pick, one is more likely to see shattered cones and a higher proportion of leaf and stem in a sample.
Some varieties are more difficult to dry than others and some tend to shatter more than others when being baled. Growers can adjust practices to accommodate these peculiarities but the more difficult a variety the more likely it is that mistakes will be made.
Certain physical properties of hop cones while relatively unimportant in the brewing process, are strongly characteristic of a particular variety. For example, Nugget has heavy dense cones while those of Tettnang are relatively light and much looser. The cones of Fuggle are markedly square in cross section. Chinook has long cones and the individual bracts (petals) are reflexed (turned back) at the tip. Light loose cones are much more prone to shatter during harvesting while heavy dense cones like those of Nugget pick beautifully as they roll well and hang together.
Hop lupulin may vary in color from pale yellow to an intense golden color. It is not known if lupulin color affects brewing performance but it is a fairly strong characteristic of a variety. It is certain that the bitter hops have much greater quantities of lupulin than the aromatic types.
Much is spoken of the organoleptic quality and intensity of dried hop aroma. These are again strong varietal characteristics. There does appear to be a general relationship between the type and heaviness of a hop aroma and the flavor and aromatic properties of a resultant beer. However, this relationship can be obscured by the manner of using the hops. A skilled, comparative aromatic evaluation of samples of one variety can detect those samples which have been picked too early or too late, over dried, or stewed. Moreover a trained evaluation can select particularly favorable growths of a variety from within the normal range of aroma exhibited by that variety in a particular season.
These are a major component of the soft resins. When isomerized, these materials provide the main bitter compounds associated with beer. The alpha acids content varies widely amongst hop varieties from levels of 3-4% w/w in aromatic type hops to levels of 13-14% in the bitter hops.
Another soft resin component, the beta-acids, are not bitter in the natural or isomerized form. Some of the oxidation products do provide bitterness, and the beta-acids can be chemically transformed into light-stable bittering forms.
The alpha acids exist in three analogous forms, humulone, ad-humulone, and co-humulone; and the proportions of these analogues vary markedly with variety. It is widely held that relatively high levels of co-humulone produce a harsh, unpleasant bitterness and have a negative impact on head retention. Although this belief is still being questioned, varieties with relatively low co-humulone levels are still strongly favored.
Oxidation of alpha acids removes their ability to be isomerized to the required bitter isomers. In comparable circumstances some varieties lose a greater proportion of their alpha acids to oxidation than do others. Cold storage and anaerobic conditions can both delay oxidation, but the innate property of a variety in this context is important in commerce. Interestingly, some oxidation of essential oil components is necessary to produce the compounds thought to be important in beer flavors so controlled ageing is important for hops required for both bittering and aromatic properties.
This characteristic varies widely amongst seasons, varieties, and growths from 0.5 mls to about 3 mls per 100 g of hops. Whilst the soft resins are responsible for providing the bitterness of a beer, the quantity and composition of the essential oils are responsible for the amount and quality of hop flavor and aroma in beer. A brewer when deciding on which varieties and how much to use will always consider the hops' contribution to flavor and aroma as well as its bittering potential.
These are four major component of the essential oils and between them they account for about 60-80% of the essential oil of most varieties. The amount of these constituents, and particularly the ratios between them, can be used as clear varietal characteristics. These compounds are all highly volatile hydrocarbons; and during boiling the wort, most if not all of them are driven off and so contribute little to hop flavor compounds, such as the humulene oxides, are thought to be positive contributors to beer flavor and hence sufficient ageing of aromatic hop varieties is necessary to allow these products to be formed.
Over a number of years a hop variety will find a particular role or niche within the brewing industry, and its particular properties will become well known and accepted. This general perception is helpful to brewers considering the use of a variety new to them.
Substitutions are a best guess based on similarities of varieties, chemical analyses, and brewer's preferences. This can be quite subjective and we have included this section only to give indications, to the best of our knowledge, in what we believe to be the best substitutions. Your preferences may be different from our opinions, and we can appreciate those opinions, since this is such a subjective area. When possible it is always nice to be able to blend an originally used variety with a substitution to minimize any flavor and aroma differences in any given beer.
This can be fairly straight forward to quite subjective, depending on individual interpretations. While we have made a general guide to what we consider the best style to use with the hops listed in this guide, we want the brewer to use their imagination in creating their own unique recipes.
Sometimes additional information unique to a variety like its release date, its relationship to other varieties, or some comment about nomenclature is important and is noted here.