What is an Alcoholometer?

Mary McMahon
Mary McMahon

An alcoholometer is a measuring device which is used to estimate the alcohol by volume in a fluid. The device does not measure the presence of alcohol directly, instead measuring the relative density of the fluid when compared to water to determine how much alcohol may be present in the mix. A number of factors including dissolved sugars and other impurities can throw off the reading, making it an estimate rather than a firm measure, but in the right circumstances, the device can be a very useful tool for people making or working with alcohols.

Knowing the alcohol content of a drink can be important for someone who consumes large amounts of alcohol.
Knowing the alcohol content of a drink can be important for someone who consumes large amounts of alcohol.

The alcoholometer is a specialized type of hydrometer. It has been calibrated specifically with alcohol in mind, allowing people to take readings from the device to measure presumed alcohol content in various products. These devices work best with distilled spirits, as they are less likely to contain impurities. With things like wine and beers, the reading can sometimes be significantly off, and the accuracy of the reading can also be complicated by a low alcohol content.

The alcoholometer consists of a tube, much like a thermometer, which is lowered into a sample of the fluid. The reading is taken by looking for the meniscus of the fluid and seeing which line on the alcoholometer it matches. Depending on how dense the fluid is, the meniscus will settle at varying points on the alcoholometer. The device can be used at various stages of the brewing and distilling process to measure and monitor the production process.

As can be seen, the device really measures density, not alcohol content, although it has been calibrated with alcohol in mind. Anything which makes the fluid more or less dense will throw the reading off. Home brewers sometimes use such devices to arrive at a ballpark estimate of alcohol content, also relying upon their experiences with previous batches and on other factors.

Knowing the alcohol content of a fluid can be important for a number of reasons. Alcohol sold for consumption is usually required to be labeled with a disclosure of the alcohol content, as this information is believed to be beneficial for consumers. Alcohols used in various industrial processes also need to be tested to confirm that their alcohol content meets the needs of the application. For example, if an alcohol is being used to sterilize, an alcohol content which is too low could cause it to be less effective, which could potentially be dangerous.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


@Azuza - I'm sorry the alcoholometer didn't work out for your brother-in-law. I'm glad that commercial meters seem to work better- I would hate to get an inaccurately measured batch of alcohol.

I know sometimes you can tell how strong something is by the way it tasted, but sometimes that doesn't work. I know I for one have gotten accidentally drunk a few times on some delicious drink that barely tasted like alcohol.


My brother-in-law brews his own beer. He tried using an alcoholometer, but he was frustrated with the inaccurate readings.

He brewed a batch of beer that supposedly wasn't that strong according to the meter. He and his friends drank two beers apiece and they all ended up rip-roaring drunk! He later told me when he was drinking it he thought it tasted a little strong but he went by the meter reading. Bad idea!

Now they just guesstimate how strong each batch is, which in my opinion is about as accurate as using the alcoholometer.


@aLFredo - I was thinking the same thing (about giving it to my home-brewing friends as a gift). I found the alcoholmeters to be relatively inexpensive but I would have to find a local store that sells them so that I could ask questions!

One of my questions would be - why do the alcoholmeters range in price from five to twenty five dollars? And are there different meters for different types of alcohol?

Living in North Carolina we have a full range of people making home-brews from muscadine wine (wonderfully delicious) to moonshine to beer and I don't know if the different processes have different alcoholmeters.


I know some home brewers and I think they would love to add something like this to their brewing repertoire! They just came over the other day and spent 5 hours brewing to make about 30 beers, but I appreciated the beer they were making because it was a dark beer and they had added chocolate for flavoring - yum!

Has anyone tried to use this device at home? Is it easy to use? Inexpensive? Might make for a good home-brewer fanatic gift as a thanks for the beer they made!

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