Is A Wine Refractometer A Good Alcohol Tester For Wine?

Refractometer With Grape Being SqueezedI have been told that a wine refractometer works real nice as an alcohol tester for my wine must and also at the end is this true?
Hello Gary,
Thanks for the great question. Testing the alcohol level of a wine is a subject that always seems to have some confusion among home winemakers.
A refractometer can not be used as an alcohol tester for wine. It will not test the alcohol level. A refractometer will only test the sugar level of a wine must or finished wine. This is no different than what a wine hydrometer can actually do. They both measure the sugar in a wine, not the alcohol.
By comparing two sugar level readings, one taken before the fermentation and another after, you can determine how much alcohol was made. This is because wine yeast consume sugar and turn some of it into alcohol. If you know how much sugar was consumed by the wine yeast, you can then determine how much alcohol was made.
This principal is exactly the same for a refractometer as it is for a hydrometer. Neither are alcohol testers, but they will allow you to calculate the alcohol level of a wine must or finished wine by comparing a current sugar reading (brix) with a beginning reading.
What makes the refractometer extremely useful — and more handy than a hydrometer in some cases — is that you can take accurate sugar readings with very small liquid samples — just a couple of drops is all that is needed. This makes it ideal for checking the ripeness of the grapes while out in the vineyard. You only need to squeeze the juice from a single grape to see how sweet the grapes are becoming. This is very valuable when trying to determine when to pick your grapesShop Refractometers.
Alternately, the hydrometer needs enough sample for it to float. This could take as much as 4 or 5 ounces of wine or must. A hydrometer jar is also needed to hold the sample. So as you can see more time and effort is involved to take a reading with a hydrometer. This pretty much rules out taking a sugar reading on the fly as you might with a refractometer.
Gary, to answer your question more directly, a refractometer is a great tool for any winemaker to have. It is very handy, and it provides a quick way to get a sugar reading almost anytime, anywhere. But a wine refractometer is not an alcohol tester. It will not directly give you the alcohol level of your wine. This can only be done by comparing a beginning reading (before fermentation) with a current reading.
Happy Wine Making,
Ed Kraus
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.

7 thoughts on “Is A Wine Refractometer A Good Alcohol Tester For Wine?

  1. Ed, most commercial grape vine growers pick about 24 brix–which usually measures out to about 12-13% alcohol. In my experience and preference for sweeter wines, I do late harvest and, using my field refractometer, don’t pick grapes until they are about 26-28 brix or about 15-16% alcohol. Commercial growers add water to bring their higher brix levels down before bottling to make it more stable, drier and not subject to ABC taxes.

  2. Hi ED
    I am not happy with this answer,ref.are not so handy they are only used to test (brix)sugar before FERMENTATION begins,after that it is a mess and home wine makers will be confused with readings(in the presence of alcohol)
    DR/Wilson from EGYPT

  3. Hi Ed,
    This was a great explanation. I used my refractometer today for the first time. I am making a Riesling type of wine kit and the instructions indicate that I need to have a Brix reading of .5%before putting the wine into another carboy. The scale goes only to 1%. So, do I wait until it gets to 1% and give it a bit more time of is there a way for me to tell if it’s OK to rack the wine into another carboy?

    • Dan, I think it would be safe to go ahead and transfer the wine to the secondary fermenter.

    • There are two types of refractometer. One is used in wine making and beer making and has a dual scale for Brix and specific gravity. Gives you a good measurement of sugar before and after fermentation of beer or wine. You can then use any number of Home brew calculators (as the conversion is the same for wine) that are available on the internet or available as apps on your phone (I prefer to use an app). Retrospectively to clarify there ARE refractometers that actually DO measure alcohol in %ABV, however these are used only for distillation of hard liquor (whiskey, gin, moonshine, rum, etc) and they CANNOT be used for wine or beer as the high sugar concentration will throw off refraction and not give an accurate reading. For a demo go to YouTube and search for a channel called Still It. He gives a wonderful demonstration of how to use a refractometer for newbies. Hope that helps.

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