Alcohol by Volume or ABV, is an important criteria in home brewing.  ABV measures the percentage of alcohol in the beer and can really impact the flavor and tasting experience.  Technology has played a significant role in measuring and controlling the ABV of beer.  Let’s go explore the ways it’s used in the home brewing industry.

Hydrometers

Hydrometers are used by brewers to measure the specific gravity of the beer – these are very important in determining the ABV. Some types can be difficult to read accurately and need to be handled carefully to avoid contamination.

Refractometers

Refractometers are used to measure specific gravity of the beer but they use a very different method than hydrometers.  They use light refraction to measure the concentration of sugar in the beer, this can then be used to calculate the ABV.  Refractometers are easier to use and require less sample volume than hydrometers, but they can be affected by temperature and other variables.

Gas chromatography

Gas chromatography is a lab technique used to measure ABV.  This method involves separating the alcohol from other compounds in the beer using a column filled in a stationary phase – then measuring the concentration of alcohol in the separated compounds.  This method is very accurate and reliable, but the equipment is expensive and thus not very practical for most breweries let alone home brewing.

Infrared Spectroscopy

This is another laboratory technique used to measure ABV.  This involves passing infrared radiation through the beer and measuring how much radiation is absorbed by the alcohol. This method is very accurate and requires less sample prep than gas chromatography, but still spendy for the equipment and not practical again for most breweries.

Digital refractometers

Digital refractometers are a newer method for calculating ABV.  They use a small sample of the beer, a light sensor then measure the specific gravity to calculate ABV.  These are very portable, easy to use and most of all provide accurate results. These are becoming more and more popular among home brewers and smaller breweries.

So, if you’re just starting out as a home brewer or running barrels through your system, you have several tools and options for calculating the ABV of your beer.  Cheers!

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