Is there sugar in wine? Is this called residual sugar?

Sugar in wine refers to the natural sugars found in the grapes (glucose and fructose).

Residual sugar is the sugar left over in the wine after fermentation. Sugar in grapes is necessary for conversion, during fermentation, to alcohol.

For dry wines, the yeast is allowed to do its thing until it has consumed all the sugar however there may still be a certain amount left in the wine.

Please note that in some cool wine areas of the world, the grapes don’t have enough sugar to give the winemakers the level of alcohol required and increasing the sugar level is allowed. Rectified Concentrated Grape Must (RCGM) is added to the juice either before or during fermentation.

There are 4 grams of sugar in a teaspoon. 

According to the Coca-Cola.com site, there are 35 grams of sugar in a 330ml can.

The below table indicates the standard level of grams of sugar per Litre per wine

South African Wine Sugar Levels:

STILL
WINES

SPARKLING
WINES