(VinePair) - Sugar is one of the fundamental components necessary to produce a successfully balanced wine and yet, at the same time, it can be one of the greatest manipulators of a wine’s final flavor.

On the fundamental side, sugar essentially creates wine. Yeast cells consume the natural sugars in grape juice and convert them into ethonol/alcohol during fermentation. This is when the magic starts, though not when it ends. Fermentation ends when the yeast cells present have consumed and converted all the sugar they can. Their role in the magic complete, the dead yeast cells rise to the top of the vat. Sugar’s role is just beginning.

When a new red wine is pressed off its skins or a new white wine is racked from the dead yeast cells, called lees, there are leftover sugar compounds. These compounds were either naturally non-fermentable or remain because the yeast cells could not convert them before they died. This leftover sugar is called residual sugar or RS.

Residual sugar is a fundamental component of a wine’s make up, along with acidity, tannin and alcohol. The interplay among these components defines a wine’s “balance.”

• Acidity cleans up the residual sugar, giving the wine depth. This leads you as a drinker to perceive the wine as clean.
• Tannin gives the wine grip, balancing the acidity and the residual sugar.
• Alcohol comes into play adding a slight sharpness to the wine, further cutting through the residual sugar.