In an attempt to make wine you and your friends put some yeast a sweet grape juice mixture in open pot After several days find that the sugar levels have dropped but there is no alcohol?

- Oxygen Exposure: Yeast needs oxygen to grow and reproduce, but too much oxygen can inhibit alcohol fermentation. An open pot allows air to circulate freely, exposing the yeast to excessive oxygen levels that can slow down or even halt the fermentation process.

- Temperature Fluctuations: Yeast thrives within a specific temperature range. If the temperature in your environment was too low, the yeast might have gone dormant, slowing down or stopping fermentation. On the other hand, if the temperature was too high, the yeast may have died, preventing fermentation altogether.

- Yeast Strain: Not all yeast strains are created equal. Some yeast strains are more efficient at converting sugar into alcohol, while others are better suited for different purposes like flavor development. The yeast you used might not have been the best choice for winemaking.

- Nutrient Deficiency: Yeast requires certain nutrients to carry out fermentation, such as nitrogen and phosphorus. If your grape juice mixture lacked these essential nutrients, the yeast may have struggled to grow and ferment effectively.

- Competing Microorganisms: Leaving the pot open could have introduced competing microorganisms, such as bacteria or mold. These microorganisms can consume the sugar and nutrients intended for the yeast, leading to spoilage and the absence of alcohol production.

Suggestions for a Successful Batch:

- Use a fermentation vessel with an airlock: An airlock allows carbon dioxide to escape while preventing oxygen from entering the vessel, creating an anaerobic environment suitable for fermentation.

- Control the temperature: Keep the fermentation environment within the optimal temperature range for the yeast strain you are using. This usually falls between 15-25°C (59-77°F).

- Choose the right yeast strain: Select a yeast strain specifically designed for winemaking and follow the manufacturer's instructions for rehydration and inoculation.

- Add nutrients: If you suspect nutrient deficiency, consider adding a specialized nutrient supplement for winemaking.

- Prevent contamination: Keep the fermentation environment clean and minimize exposure to external microorganisms by using sanitized equipment and avoiding unnecessary stirring or opening of the fermentation vessel.

By addressing these potential issues, you can improve your chances of successful winemaking and enjoy a delicious homemade alcoholic beverage.