Image above by Kevin from The Beginning at Last
Beer Styles
Look at that happy and friendly beer muse above. That is Kevin’s picture. Wouldn’t you like a beer? I like beer and I also brew beer at home. My dog Rollo loves it when I spill wort on the kitchen floor. The wort is what you have before fermentation. It is like a grainy sticky sweet soup, and he likes to lick it up. However, my wife does not like it when there’s sticky wort all over her kitchen floor and the stove. Everyone has their own perspective.
Beer is one of the oldest alcoholic beverages in the world, dating back over 7,000 years to ancient Mesopotamia. There are more than 100 different styles of beer worldwide, with the main categories being lagers and ales. The beer advocate currently lists 120. Below are a few examples of Lagers and Ales.
Lagers : Pilsner, Märzen (Oktoberfest), Adjunct Lager, Pale Lager, Scwarzbier (a black lager), Bock.
Ales : IPA, Stout, Porter, Wheat Beer, Belgian Beer, Blonde Ale, Saison, Barley Wine, Lambic, Geuze
Brewing Beer at Home
When you brew beer at home you start by boiling the wort. You boil water and you add the malts and the hops for the flavoring and the aroma at specific times. This all depends on the recipe you are following. Warning! The wort easily boils over. Then you cool the wort (I use an ice bath to do this), add the yeast, and you let it ferment, typically for a couple of weeks.
You can add various things for flavoring, such as whiskey infused wood chips if you want your beer to have a taste of whiskey and wood (yes, I have done that). Whiskey and wood are great added flavors in stouts. After the two weeks of fermentation, you add sugar and bottle the beer and let it ferment for a few weeks before you put it in the fridge.
A few words about the bottling process. The bottling process below is using siphoning instead of pouring to achieve some filtering and to avoid splashing. Splashing can cause excessive oxidation which can ruin the beer the same way bananas turn brown. This seems to matter for New England style IPAs, but not so much for other beer styles (my observation).
Measuring the alcohol content in home brews
When you brew beer at home you don’t have the advanced equipment that breweries sometimes do so measuring the alcohol content is a challenge. However, you can do it with an indirect method using a hydrometer. I will explain how to do this. There are instruction booklets, books and online websites that explain how to do this, but I will keep it short and succinct.
During the fermentation process, yeast converts sugars into alcohol (and carbon dioxide). As the sugar is used up, the wort slowly becomes less dense. By measuring the density before and after fermentation (using the hydrometer), you can calculate how much alcohol is in the finished beer. In the beer world this is called measuring the gravity, not to be confused with the fundamental force of attraction between objects with mass. You can buy a hydrometer in a lot of places including Amazon.
The density/gravity of water is used for reference as 1.000. To be exact, it also depends on the temperature, but for now we’ll ignore that. After the initial boil of the wort, and before you add the yeast, there is no alcohol in the wort. This is a good point to measure what is called original gravity (OG).
I should mention that you need to let the wort cool off before doing your measurement. The temperature at this point should be around room temperature, 72 degrees (60 to 75 degrees). Then after fermentation (in your container, carboy, whatever) you measure it again. This is called the final gravity (FG).
I should add that after the fermentation in your container/carboy is done you add a little bit more sugar (called priming sugar), you bottle the beer, and you let it ferment a little bit more, which will add a little bit more alcohol as well as carbon dioxide. You want some carbon dioxide in the beer but not too much. This extra amount of alcohol is not accounted for using the final gravity. However, it is typically around 0.2% and if you wish to include it, you can just add that number.
Using the original gravity (OG) and the final gravity (FG) you can now calculate the ABV, Alcohol by Volume, by using the formula below. For this brew, an IPA (India Pale Ale), I got OG = 1.072 and FG = 1.018. Ideally FG is around 1.010, but for whatever reason I did not get there.
ABV = (OG – FG) x 131.25 = 0.054 x 131.25 = 7.1%
So that would be 7.3% with the bottle fermentation. That is a good enough measurement, but if you want precision, there is a more exact formula.
ABV = (76.08 x (OG – FG) / (1.775 – OG)) * (FG/0.794) = which in my case yields ABV = 7.23% which would yield 7.43% with the bottling. I can add the recipe predicted ABV = 7.5%. There are even more exact formulas that account for the temperatures at the points of measurement of original gravity and the final gravity. But that would be really nerdy.
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