WSET Level 1 Practice Question · Episode 15
Show Answer & Explanation (try the quiz first)
Practice Question
During the winemaking process, what are the three main products created when yeast consumes the sugar in the grape juice?
- A. Water, Oxygen, and Nitrogen
- B. Alcohol, Carbon Dioxide (CO2), and Heat
- C. Sugar, Vitamins, and Minerals
- D. Color, Tannin, and Maturation Aromas
Answer & Explanation
Answer: B. Alcohol, Carbon Dioxide (CO2), and Heat Explanation: Fermentation is a chemical reaction where yeast consumes sugar to gain energy. During this process, alcohol is produced, turning the juice into wine. Additionally, carbon dioxide (CO2) gas is released, and heat is generated as a byproduct of the chemical reaction. In red winemaking, this heat also helps with the extraction of color and tannin.
Key Theory Summary
Fermentation is the sacred equation that marks the birth of wine. 1. The Equation: Sugar + Yeast → Alcohol + CO2 + Heat 2. The Role of Yeast: Yeast, which is either naturally present on the grape skins or added by the winemaker, breaks down the sugar. 3. Stopping Fermentation: If the yeast consumes all the sugar, the wine becomes 'Dry'. If the process is artificially stopped early, the wine becomes 'Sweet'.
Expert Exam Tip
[Trap]: Thinking "Carbon dioxide is only needed for sparkling wine" is a mistake. Carbon dioxide is produced during ALL fermentations. The difference is that in still wine production, it is allowed to escape, whereas in sparkling wine, it is trapped inside the bottle. [Tip]: In the exam, whenever you see the word 'Fermentation', immediately associate it with the 'Alcohol, CO2, Heat' trio. This equation is the foundation of wine science.