Which process converts sugar and yeast into alcohol and carbon dioxide?

• A. Crush
• B. Maceration
• C. Press
• D. Fermentation

Answer: (D)

The main concept is fermentation, the process where yeast consumes sugars and produces alcohol and carbon dioxide. In wine-making, grape juice provides sugars like glucose and fructose. When yeast is present, it metabolizes those sugars anaerobically, turning them into ethanol (alcohol) and carbon dioxide. The CO2 bubbles off, while the alcohol remains in the liquid.

Crushing is just breaking the fruit to release juice, not converting sugar to alcohol. Maceration is soaking crushed fruit to extract color, flavor, and tannins from the skins—again not about producing alcohol. Pressing extracts juice from the solids, but the conversion from sugar to alcohol happens during fermentation, powered by yeast.