After 48 hours at the high temperature, the wine is allowed to stand over night at room temperature. Then the wine sample is carefully inspected for protein haze or sediment. The free sulfur dioxide content of all wines should be measured and raised to about 30 milligrams per liter a few days before bottling. Bottling wine with less than 30 milligrams per liter of free sulfur dioxide will result in a short-lived product. Residual Sugar Wines containing more than 0.2 percent residual sugar are not biologically stable, and these wines can start fermenting anytime.
Most wines are a complete loss when fermentation restarts after the wine is bottled.
To avoid such catastrophic losses, additional precautions are always required when off-dry or sweet wines are bottled. Generally, four methods can be used to deal with the residual sugar problem. The wine can be pasteurized to kill the yeast. Sterile filtration can be used to remove all of the yeast cells when the wine is bottled. A special material can be added to prevent yeast in the wine from fermenting the residual sugar.