Our ancestors were aware of hops; however there is no compelling evidence to suggest that the first brewers actually used hops. The first record of hopped beer comes from pot remains dated around 0 C.E. a quite unexpected location, northern Italy, a detail which I imagine angers many Germans.
Hops emerge in our medieval records around 800 C.E., with suggestions of their use in beer around one century later. The runaway success of hopped beers seems to have started in northern Germany, possibly in Bremen, and swiftly found their way to trading league cities such as Hamburg. It took another century, but sooner or later the Dutch learnt how to create hopped beer, and another century later, the Flemish did too. By around 1420, hops made the jump and landed in Kent, southern England, this is still the main hop growing region in Britain today. In 1600, their fresh, bitter aroma, and preservative value could be found in pretty much every beer in Europe. Even at the beginning, it was clear that particular areas produced good-quality hops. All the present hop-growing regions have been growing and trading hops for many centuries. Hops necessitate a particular midsummer-day length in order to stimulate cone production, as such; cultivation is limited to particular latitudes. Moisture and drainage needs are also extremely specific; hops are a fairly fragile plant, in danger to numerous pests and diseases.
In the entire world, just a few places have the correct environments to produce great hops. The flaming orange soil of the Goldbach Valley in western Bohemia, close to the rural town of Saaz, and the Mittelfrüh sub-region of the Hallertau are two of the most famous. Wine experts use the phrase terroir to denote that certain combination of climate, soil, and all the other factors which makes a wine from one specific region unique from all others. Beer isn’t as terroir-dedicated as wine, but hops definitely display it in full measure.
Not many regions had more than one hop variety which grew well, and turnover in breeds was measured in centuries, so hops emerged naturally and were titled by the areas in which they were grown. Lots of these cherished old varieties still give great service. In recent times, the production of new breeds has increased at a ridiculous rate, meaning we have plenty of new flavour possibilities emerging. I personally used to feel I had a pretty understanding of hop varieties, however these days it seems there is a new one to learn every week.
Hops’ Structure and Function
Hop cones, after they’ve been harvested and dried, come either packed “whole,” with no further processing, or shaped into pellets. Dried hops are finely crushed and put through a circular die, producing small pellets glued together by the resins from the hops. While pellets are the more common appearance, some homebrewers believe that whole hops have fresher flavours due to their cellular membranes not being destroyed by the pelleting process. However there are problems with whole hops, they aren’t too compact, they don’t store particularly well and only a few types are obtainable by homebrewers. Processing hops further presents different aromatic oils and bittering compounds, but these constituents are not commonly often in homebrewing.
Hops provide a number of different qualities to beer. Besides the bitterness and pleasurable aromas, hops offer some antibiotic against gram-positive (an extensive class of bacteria which includes beer-spoilage organisms Lactobacillus and Pediococcus) bacteria, which results in the beer being more stable. Hops also hold chemicals known as tannins (polyphenols) which are attracted to proteins in during the boil, facilitating the removal of unwanted, long-chain proteins from the wort. The outcome is a sharper beer in the end. The bitterness originates from the alpha acids, and also the related beta acids. Every hop crop is examined and traded with an alpha acid percentage which ranges from 2 to nearly 20—this signifies its bittering potential. Hops, obviously, have significantly different aromas; however the quality of the bitterness is always the same, although the percentage may differ. Aroma oils also differ, unfortunately there is no common available analyse for this, this is one reason why brewers often evaluate hops them prior to purchasing.
Alpha acids aren’t stable; both time and temperature have an effect on their bittering power, this is why hops usually stored cold or frozen, and with restricted access to oxygen. Some kinds are more volatile than others. Though the specifics do vary, even hops which are correctly stored can lose a third or more of their bittering power in one year. If you’re a homebrewer who desired a well-tuned brew, you’ll need to take this into account if you’re using hops which are a few months old.
Brewing With Hops
In its unprocessed state, alpha acid is not particularly bitter or even very soluble. An energetic boil is required in order to make a chemical change, known as isomerisation, in which some parts of the alpha acid molecule are rearranged; no atoms are added or lost during isomerization. The amount of alpha acid isomerization rises with boil time. The majority of it will take place within the first hour, but minor increases continue to happen for around another two hours. Afterwards, the wort becomes less bitter due to the degradation of alpha acids. The quantity of bitterness obtained from the hops is known as utilization, and is given as a percentage, typically somewhere in the region of 5 to 30 percent for homebrewers, and is affected by a number of variables, such as time, pH, wort gravity, boil temperature and vigour. The amount of bitterness varies significantly from beer to beer, and is a vital parameter of any style. It ranges from under 10 BU (Bitterness Units) for beers which are lightly hopped, including American adjunct lagers and German wheat ales. All the way to 70 BUs for double IPAs. People have been attempting to make beers bitterer than this; however it has stalled due to solubility limits at around 100 BUs; however there are still people attempting to climb even higher.
Boiling removes a lot of aromatics, therefore to keep this aroma hops need to be added later in the boil. Aroma hopping can be carried out a few different ways: either in the last 5 or 10 minutes of the boil, right at the end of the boil when the flame has been switched off, running the hot wort through hops in a tool known as a hop back, or later through conditioning, or in the serving cask, this is the technique used for real ales. The method of adding hops to beer during the conditioning phase is known as “dry hopping” and is prevalent when making IPAs and other hop focused beers.
An additional technique known as “first wort hopping” is also used to add hop character. Aroma hops are inserted to the kettle as the wort is run off the mash, producing in a luscious hop aroma and flavour. This does present additional bitterness, around a third of what could be anticipated from a full 60-minute boil. Though the mechanism is still unknown, it is believed to concern compounds known as hop glycosides, chemicals in which various hop aroma elements are stuck to sugar or other carbohydrates. Providing that the aroma components remain stuck to the sugars, they aren’t unstable; therefore they can endure the boiling and fermentation processes. These chemicals are vital for good hop flavour. The compounds are fairly different from the aromatic hop oils, contributing a lot of fruity and spicy character.
Beer is usually brewed with hops which have been dried; but a common harvest specialty these days is “fresh hopping,” using fresh hops straight off the vine. Undried hops are not usually obtainable commercially; therefore lots of homebrewers and small breweries are harvesting hops which are grown locally. These fresh hopped beers are tend to have fresher, “greener” aromas and a particular just-picked sharpness.