Residual Sugar Testing

Knowing where your wines residual sugars are at is an important part of winemaking. Dry wines should contain less than 2 g/L (0.2%) RS (residual sugar) to be considered stable. If you choose to have residual sugar levels that are higher than this in your wine, that is fine, but then you will need to make sure to properly stabilize the wine before bottling. This is done by making sure the free SO2 level is correct and, if possible, doing a 0.45 Absolute micron filtration as well. 

Accurate Residual Sugar Testing:
Hydrometers are a great tool to get a rough idea of the residual sugar content of a wine, but only a Clinitest will give a clearly defined, set value you can definitively work with. To use the kit, simply place 0.5 mL of wine into the test tube and drop a tablet into it. The tablet will react with the wine and boil for a few seconds until it dissolves. As it boils, it will change color. Once the boiling stops, wait 30 seconds and compare the color in the sample tube to the color chart for the results.

Helpful Hint:

• Dry red wines are usually in the 0.05 g/L RS range
• Dry white wines are often under 1 g/L RS. 
• Residual sugar is one of the elements that can bind free SO2 in your wine. So if you have residual sugar above 2 g/L in your wine, make sure to watch your free SO2 levels carefully to avoid them falling too low.