Using A Hydrometer To Adjust Wine Sweetness

Adjusting Wine Sweetness With HydrometerMost wine recipes give a SG [specific gravity] for starting fermentation and at the completion of fermentation. My wine usually ends up dry, so when I bottle it I usually stabilize it and back-sweeten most of it. I've been just adding sweetener a little at a time and tasting until I think it is about right, but that's a little hard to hit and very unscientific.

What about using a hydrometer to adjust wine sweetness and is there an approximate hydrometer reading for what they call dry, semi-dry and sweet?

What about white table wines, red table wines, sweet table wines, dessert wines etc do all of these different wines fall under the same category of dry, semi-dry or sweet?

Glen L. – IA
Hello Glen,

While there are certain ranges on the specific gravity scale that one could consider sweet verses dry, these ranges are so narrow on the typical wine hydrometer that it would be very hard to accurately apply them to sweetening a wine. In fact, I could not really tell you what the ranges would be because I have never paid that much attention to them.

There are also a couple of other reasons why using a hydrometer to adjust wine sweetness is not all that practical:

  • Shop Wine ConditionerYou could have two different wines sweetened to the same specific gravity reading and they could have very different impression of sweetness. What is coming into play is how the other flavor components of the wine work with the sugar to form the wine's character. As an example, if the wine is rich and earthy as opposed to crisp and fruity, then more sugar may be needed in the former case than in the later wine to achieve the same impression of sweetness. This is all subjective, of course, but the principle rings true.
  • A wine's body or lack of body could cause two wines that taste equally dry to have two different readings on the wine hydrometer. Body raises the specific gravity without raising sweetness. In this case, if you have a full-bodied wine and a thin, crisp wine and you sweeten them both to the same reading on the specific gravity scale the hydrometer, the full-bodied will have less residual sugar than the thin crisp wine. Part of the SG reading is being made up with body, not sugar.

So as you can start to see, depending on hydrometer readings to adjust your wine's sweetness may not be as accurate as just tasting the wine. After all it is how the wine tastes to us humans – and more specifically, you – that matters most, not what the hydrometer says.

The wine industry does use a sweetness scale to give customers a clue as to how sweet a wine might be before they purchase it. The scale goes from 1-9 with 1 being the driest, and it is based on percentage of sugar by weight in the wine. While this scale may be used as a marketing tool, I find it hard to imagine any commercial winemaker setting out to target a particular number, rather they would do just as you are doing – going by how the wine tastes and how sweetness is working in concert with the wine' other characters.Shop Hydrometers

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.