How to Measure Alcohol Content

Using an Alcoholmeter

Use an alcoholmeter calibrated to the density of pure ethanol. An alcoholmeter is a hollow glass tube that floats in a liquid. Because alcohol is less dense than water, using a specialized hydrometer that is specifically designed and calibrated to measure alcohol content called an alcoholmeter allows you to measure the alcohol content of a liquid. Alcohol meters are used to measure the alcohol content of high-proof spirits. Check the packaging to make sure your alcoholmeter is calibrated for measuring alcohol content.

Fill a clean container with the alcohol. Use a clear jar or a glass cup that is big enough to allow the alcoholmeter to float in the liquid without hitting the sides or bottom. Pour the alcohol you want to test into the container. Fill the container until it’s about about ¾ full. Most alcohol meters are about 10–12 inches (25–30 cm) long. Leave enough room so the alcoholmeter doesn’t cause the liquid to overflow when you add it.

Lower the alcoholmeter into the liquid. Gently place the bulb side of the alcoholmeter into the liquid that you’re testing. The alcoholmeter should float freely in the center of the liquid. If it rests against the side of the container, move it back toward the center.Tip: Hold the alcoholmeter by the end as you lower it to prevent the oils or dirt from your fingers getting into the liquid and affecting the reading.

Rotate the alcoholmeter to remove any bubbles attached to it. In order to accurately read the alcohol content, the alcoholmeter needs to be free of any bubbles. Gently spin the alcoholmeter floating in the liquid to release any air bubbles that may be attached to it. Allow the hydrometer to stop spinning on its own and settle back into the center of the container.

Look at the bottom of the meniscus on the alcoholmeter. The surface tension of the liquid will form an arc on the side of the hydrometer. Check the bottom of this arc in order to get an accurate reading. The number at the meniscus will tell you the proof of the alcohol in the container. The proofing scale number on the alcoholmeter corresponds to a percentage of alcohol content. So if the number at the meniscus reads “65,” then the liquid in the container has an alcohol content of 65%.

Proofing with a Distiller’s Parrot

Use a distiller’s parrot to measure the alcohol content of distilled spirits. A distiller’s parrot is a device that holds a spirit hydrometer, also known as an alcoholmeter. The alcohol is poured into a collection cup at the top, down the tubing and into a chamber that holds the alcoholmeter, allowing you to view the proof of the alcohol. Use a parrot for spirits with high alcohol contents. Don’t use a parrot for beer, wine, or liqueurs as the sugar content will affect the reading.

Insert the alcoholmeter into the parrot. Place the alcoholmeter into the holding chamber of the parrot. Lower the bulb end gently. There isn’t any liquid in the container so if you drop it in, it could crack or break the alcoholmeter. Hold the alcoholmeter by the end of the stem to keep it clean from oil and dirt that may be on your fingers.

Set a clean container beneath the spout of the parrot. When you pour the spirit into the parrot, it will run out of the spout at the other end. Place a clean container beneath the spout to collect the alcohol as it pours out of it.Tip: Use a clean, clear glass jar so you don’t contaminate the alcohol with dust or dirt.

Fill the parrot with the alcohol. Once you’ve placed the alcoholmeter into the parrot and placed a container to collect the runoff, pour the alcohol into the collection cup. Add enough alcohol to completely fill the chamber with the alcohol meter. The alcohol should start to pour out of the spout into the container beneath it.

Read the scale on the side of the alcoholmeter. As the alcoholmeter floats in the chamber, take a reading at the bottom of the meniscus, or the arc in the liquid against the alcoholmeter. This reading will give you the proof of the alcohol and tell you its alcohol content. For example, if the number at the bottom of the meniscus is “97” then the alcohol content is 97%.