If you are wondering how to use a hydrometer to measure alcohol in your homebrew or distilled spirits, then this is the guide for you.
Hydrometers are one of the most important tools for brewers and distillers as it allows them to accurately measure the ABV (alcohol by volume) of their beverage. Thanks to the specific gravity of a liquid, it is possible to calculate the ABV of any alcoholic beverage with the help of a hydrometer.
By measuring the specific gravity of the alcohol brewers can make sure that their beer or spirit recipe is consistent from batch to batch and can use this information to make adjustments if needed.
Let’s learn more about the process of using a hydrometer!
What is ABV?
The ABV or alcohol by volume gives you an indication of the strength of your beer or distilled spirits. It is typically expressed as a percentage, with higher percentages representing stronger beverages.
For brewing beer, brewers need to be specific about the ABV so that they can accurately replicate each batch. The higher the ABV, the higher amount of alcohol present in the beer.
Even for some sweet wines and ciders, ABV is important, as it is the amount of residual sugar in the beverage, which affects its taste and sweetness.
What is a hydrometer?
A hydrometer is an instrument used to measure specific gravity of liquid solutions, also known as the density of a solution relative to pure water. This is important in determining the alcohol content (ABV) by weight of fermented beverages like beer and typical wine (wine thief or wine juice, for example)/sweeter wine.
It is comprised of two main parts: a stem with a bulb-shaped weighted end, and an adjustable float. The float is set to the liquid’s surface and, depending on the specific gravity of the solution, it will sink or rise in the liquid indicating a corresponding ABV value.
The original gravity (OG) on a Brix scale is taken as soon as the wort (unfermented typical beer or wine/sweeter wine) has been made. This helps in determining the final ABV since it gives you a reference point to work from.
And the final gravity (FG) on a specific gravity scale is taken after fermentation has been completed. This helps in determining the actual ABV of the beverage since it gives you a reference point for changes in specific gravity during fermentation.
Hydrometer reading
If your hydrometer has one or more scales printed on the hydrometer scale, you can use it to measure the specific gravity of a liquid. To do so, fill the jar with the liquid and insert the hydrometer. Give it a spin to remove any air bubbles, then let it settle on its own.
Wait until the hydrometer has stopped before taking specific gravity readings from the appropriate scale. The liquid temperature must be 60°F (15.5C) for an accurate measurement; if not, make adjustments to your specific gravity reading.
To read a transparent liquid, place your eye slightly below the surface of the liquid. Slowly raise your eye until you see an ellipse. Once the ellipse appears as a straight line, record the point on the hydrometer scale.
If the liquid is not clear enough to read from the surface, you will need to hold the hydrometer above the liquid and estimate as accurately as possible where the liquid rises on it.
Conclusion
Using a hydrometer is an important part of making sure you get the correct ABV measurements for your beer. With some patience and practice, it can become an easy process that will help to ensure your brews turn out as expected. By following the steps outlined above, you can accurately measure the specific gravity of liquids and use the accurate reading to calculate the alcohol content of your beer. Happy brewing!
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