Homebrewing has become a very popular pastime among beer enthusiasts. The pride that goes along with creating and sharing one's own personal brew is almost as enjoyable as consuming the finished product itself. While homebrewing is a relatively easy hobby to break in to, it is still by its very nature a technical discipline, and that means that you can expect to encounter a number of terms and phrases in the beginning that may be confusing. Much of the slang of the homebrew process is taken directly from chemistry and microbiology, while other bits and pieces are unique to brewing. This article presents a few of the more commonly encountered brewing terms and phrases that often leave newcomers scratching their heads.
It is not unusual to hear experienced home brewers discuss the relative merits of bottom-fermenting and top-fermenting yeasts. If you listen to such discussions long enough, you are sure to hear the words "aerobic" and "anaerobic" thrown in as well. Bottom-fermenting yeasts do not require oxygen in order to complete their metabolism whereas top-fermenting yeasts do require oxygen. Since "aerobic" indicates a process that requires oxygen and "anaerobic" is the opposite, it is clear that bottom-fermenting yeasts are anaerobic, whereas top-fermenting yeasts are aerobic. Note that top-fermenting yeasts are unable to metabolize many types of sugar, which means that beers that use top-fermenting yeasts will often have a more sweet and fruity taste than beers that utilized the anaerobic bottom-fermenting yeasts.
Another commonly used bit of jargon that one encounters in the micro and homebrewing world is the international bitterness unit (often referred to by its abbreviation IBU). The IBU is a precise way to measure the bitterness of a beer as a function of the hop content. The IBU calculation depends both on the concentration of hops in the beer as well as the composition of the hops.
It is not uncommon to encounter the term "light-struck" in reference to homebrew beer quality. This term refers to the unique and unpleasant aroma that occurs when beer (specifically, the hops in beer) is exposed to excess light. The chemical reactions that occur when chemicals contained in hops are exposed to a large quantity of light result in the creation of certain compounds that have a notoriously pungent odor. In fact, these compounds are identical to those utilized by skunks in their well known defense mechanism. Therefore, if you ever hear someone refer to their beer as "skunky", you can be certain that they are referring an odor reminiscent of skunk oil that is created when a beer is "light-struck".
You will often encounter the term "priming" in reference to refining the fermented beer just before bottling. Priming is the act of giving the yeast a boost of sugar after the main fermentation process. Priming serves two purposes--in the first place, the added metabolite source encourages that yeast to increase their output of carbon dioxide, which means that the beer will be more carbonated. This is the typical reason for priming a beer. Another effect of priming is that the extra fermentation that occurs when a beer is primed causes the alcohol content to rise slightly.
This article has introduced only a few of the most commonly used terms in the world of homebrewing. There are many more that you will undoubtedly encounter as you delve deeper into this satisfying hobby. Many homebrew books for beginners feature a glossary that can help you out if you get stuck on a particular term. The homebrewing community is also a great resource as brewers are always happy to lend their experience and expertise. If you are interested in pursuing homebrewing, then don't let the terminology scare you away. The jargon is fairly limited and, after a few months, you'll feel right at home talking about IBUs, priming, and all of the other technical details that are a part of the fun of homebrewing.
