Are the hops in your beer alpha or beta acid dominant?
Last weekend I was at The Chesapeake – Real Ale Festival in Baltimore, MD where 20 or so beers were represented. Though majority were not, some were labeled with the type of hops they were brewed with.
Have you ever looked into how beer is brewed and specifically the role hops play? My interest was piqued…
To understand the role hops play, check out this process flow of how beer is made and then see if you can find how your favorite brewery brews beer. Here’s Guinness for example.
In the beer making process, after barley is malted, milled, mashed; the resulting concoction, wort (pronounced wert), is ready to be brewed, and seasoned, so to speak, with hops.
Hops have two primary chemical compounds that create flavor and aroma; alpha-acids and beta-acids:
Alpha-acids (can be notated as α-acids) are what makes beer taste bitter. During the brewing process alpha-acids must be brewed so that they isometrize (chem lingo for a compound keeping the same molecular formula, but changing its structural formula) by heat, release flavor, and become iso-alpha-acids (1) (4).
Beta-acids (can be notated as β-acids)are only slightly bitter, lose most of their flavor while brewing and do not isometrize like their alpha-acid counterpart (2).
Since the beta-acids compounds are delicate and evaporate quickly, finishing hops or high beta-acid hops may be added toward the end of the brewing process to develop the aroma of the beer (2) (3). Bittering hops tend to have higher concentrations of alpha-acids, and aroma hops have lower concentrations of alpha-acids (2).
So, aside from hops’ chemical behavior, what the heck are they? BeerAdvocate.com summarized it best:
Humulus Lupulus (hops) are the flowering cone of a perennial vining plant and a cousin of the cannabis variety (sorry no THC in this stuff) that typically thrives in climates similar to the ones that grapes do. Hop plants are dioecious, meaning the males and females flower on separate plants – and the female cones are used in the brewing process. Hops are the age old seasoning of the beer, the liquid gargoyles who ward-off spoilage from wild bacteria and bringers of balance to sweet malts. They also lend a hand in head retention, help to clear beer (acting as a natural filter) and please the palate by imparting their unique characters and flavours. Basically, hops put the “bitter” in beer.
To finish describing the beer process loop, once beer is brewed, it goes through a separator to remove the hop cones (and so you know, hops are usually boiled in cone form, but they also come in powdered compressed form which yields to easier extraction (4)), cooled, fermented, matured and packaged.
Now that you know a little about hops, what kinds are there? Here’s a number of hop variety lists: one, two and three including info such as descriptions, types and their α-to-β-acids percentages.
Next time you are at a tasting, a bar or some undisclosed location enjoying beer…pause to analyze how your beer was seasoned. Is it alpha or beta or both?
Sources:
(1) Hop guide. (2012). Retrieved from http://beeradvocate.com/beer/101/hops
(2) Hops. (2012). Retrieved from http://en.wikipedia.org/wiki/Hops
(3) Nice, K. (n.d.). How beer works. Retrieved from http://science.howstuffworks.com/innovation/edible-innovations/beer2.htm
(4) Beer. (2012). In Encyclopædia Britannica. Retrieved from http://www.britannica.com/EBchecked/topic/58378/beer/66626/Mixing-the-mash