After previous charts describing bitterness, gravity and colour, I’ve decided to continue my exploration of the BJCP style guide. This time I’m looking at beer alcohol content.
I want to be honest and confess that I’m generally not interested in the alcohol content of home brew.
Provided it’s more or less within range I’m happy. Other than approximate checks to make sure a session bitter isn’t 8% or that a barley wine isn’t watery, I’m not too bothered.
I imagine many of you are the same.
However, in the spirit of completeness, I’ve continued to investigate the BJCP numerical guide to beer (a.k.a the style guide). Previously I’ve covered bitterness, original and final gravity and beer colour.
The BJCP guide contains descriptions and statistics for all categorised beer styles. In some ways it’s unrealistically precise, on the other hand it’s a way of comparing and contrasting different brews from around the world.
I don’t think about beer in such meticulous terms, but the guide is a useful starting point when planning a brew.
It suggests types of beer and combinations of ingredients that you possibly hadn’t condsidered before, and often opens up new avenues of beer exploration.
To round off this series I’m going to use the guide to design a beer recipe from scratch – check back soon.
Alcohol in Beer
Alcohol is one of the beer ingredients that we think least about. Perhaps because it’s not something added, but magically produced.
The basic premise of beer making is that yeast convert sugar in wort to alcohol and CO2 in a process known as fermentation.
The reason this works is because it takes advantage of the reproductive process of yeast. In order to multiply they take in sugar, naturally producing gas and alcohol as they go.
They expand in numbers quickly, which explains why fermentation is a vigorous activity and why relatively little yeast is needed to ferment a full batch of home brew.
After consuming all fermentable sugar the yeast drop to the bottom and the fermentation stops.
In wine making the amount of alcohol reaches levels where yeast can no longer live. Beer making, however, is usually limited by the number of fermentable sugars in a particular wort.
To make extra-strong alcoholic drinks additional techniques are used. For instance, distillation in whisky making which concentrates the alcohol through a process of evaporation.
Alcohol in Home Brew?
Alcohol in beer is measured precisely in laboratories. You can also estimate it at home by taking gravity readings during the brew.
Just before you pitch the yeast into the fermenter on brew day, use a hydrometer to measure the original gravity. This will tell you the amount of sugar in the wort.
Then, just before bottling or kegging, take another reading. This will give you the final gravity. If the fermentation has worked there will be less sugar, with alcohol and gas in its place.
Using these two numbers (original and final gravity) you can approximately determine the alcohol content by referring to a chart such as this one here.
Chart of Beer Alcohol Content by Style
Alcohol in beer is usually expressed as percent by weight. The BJCP guide adheres to this tradition.
For every beer style a target range of ABVs is suggested. This is one of the variables, along with bitterness, original and gravity and beer colour that you can tweak when designing recipes.
If you prefer, a pdf version can be found here: chart of beer alcohol content.
Whether or not you consider the alcohol content of your beers important, it’s certainly one more variable to bear in mind when designing your brews.
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