Glycerine, also known as glycerol, is a natural sugar alcohol that is found in many fruits and vegetables, including grapes. It is a versatile additive that can be used in winemaking to improve the mouthfeel, sweetness, and body of wine.
 
Glycerine is a colorless, odorless, and viscous liquid that is soluble in both water and alcohol. It is a non-fermentable sugar, so it will not add alcohol to wine. However, it will add sweetness to wine and make it feel more full-bodied and viscous in the mouth.
 
Glycerine is often used in winemaking to improve the mouthfeel of red wines. It can also be used to sweeten white wines or to add body to lighter-bodied wines. Glycerine can be added to wine at any stage of the winemaking process, but it is typically added after fermentation is complete.