Welcome to the new “How to Talk Like A Beer Geek” A-to-Z addition!
Okay class, settle down, and please take your seats!
Dan, I said DAN! Put that refractometer away, and take your seat please! Quickly now!
Class is now in session. In this class we will be taking a look at commonly used terms in the brewing industry, and break them down so that next time you are at the brew pub with your friends, you too can Talk Like A Beer Geek and impress the masses. So grab your pencil and note book, and kick back with us! Prost!
Today in How to Talk Like a Beer Geek we will be talking about the letter A:
A is for Attenuation: Now let me start off by stating that the word Attenuation as two meanings, one in the scientific world, and one in the brewing. Scientifically speaking attenuation is the reduction of strength of a signal. For example when light hits water it loses strength the deeper it goes. The red, yellows, and orange light gets absorbed first by the top layer of water, and as it gets deeper you are left with the blues and violets. This is why large bodies of clear water looks blue, like the ocean.
In brewing “Attenuation” takes on a whole new meaning, but with some familiar properties found from the scientific definition. In brewing we are talking about how much of the fermentable sugars are being converted by the yeast. So in essence we are talking about the reduction of fermentable sugars from the wort/unfermented beer. Generally, beers with higher attenuation will have a drier taste, and be more alcoholic than a beer produced with the same wort, but had the fermentation process stopped before it reached full attenuation. Attenuation can also cause problems if they are under-attenuated. Beers that are under-attenuated will be more cloyingly sweet. While this my not be as noticeable in some bigger beers, it will be greatly noticeable in small ABV beers, and lighter beers. This can sometimes be fixed by brewers by activating the yeast. This can be done by agitating the yeast, getting the yeast to the proper temperature, and other various tricks of the trade for a crafty brewer. However if the yeast has died out at this point, it could signify that the batch is heading for the drain.
Brewers can measure attenuation by measuring gravity with a tool called a hydrometer:
When a brewer is finished with the boil or cooking process of the beer they take a gravity reading using the hydrometer. This reading is called the “Original Gravity”. We will talk about gravity in a future article, but for now it refers to the density of a certain compound. Now as the wort sits and begins its long journey into becoming beer, it has to attenuate first. The brewer will often collect samples of the beer and monitor the “Current or Final Gravity”. Then using a formula they can reach the “Specific Gravity”. Here is that formula:
This formula will help produce a number that will tell the brewer how close the beer is to finished, and also how much alcohol is in the beer.