Residual sugar is the natural sugar left in a fermented beverage, most often wine, after fermentation stops, whether because the yeast consumed all the sugar it could or because fermentation was deliberately halted early. It isn't sugar added afterward; it reflects how much of the original sugar converted to alcohol. Residual sugar shapes body and perceived sweetness and is used to classify wine style, roughly from bone-dry (under about 1 gram per liter) to dessert-sweet (over 45 grams per liter), with legal 'dry' thresholds varying by region and grape acidity. It also affects the character of spirits distilled from sugar-rich bases, such as rum or whiskey, and matters in jam and preserve-making, where it affects set and shelf life.