Key factors inhibiting wine fermentation:
1. Abnormal temperature: Temperatures exceeding 30℃ or falling below the optimal range (20-30℃ for primary fermentation, 10-20℃ for secondary fermentation) will inhibit yeast activity and may even cause fermentation to stop.
2. Oxygen imbalance: Insufficient oxygen supply will result in insufficient yeast numbers, while excessive oxygen supply may lead to over-proliferation or oxidation problems.
3. Excessive sulfur dioxide: Adding too much sulfur dioxide will directly poison the yeast, affecting its reproduction and metabolism.
4. Raw material problems: Mold, damage, rot, or pesticide residues in grapes will inhibit yeast growth.
5. Low pH: When pH < 3.0, yeast fermentation capacity decreases significantly, easily generating volatile acids or ceasing activity.
6. Accumulation of fermentation products: Excessively high alcohol concentration or substances such as fatty acids produced by yeast metabolism will inhibit the continued fermentation process.