Aeration and agitation are necessary for ethanol production because they provide oxygen and help mix the fermenting mixture. Oxygen is necessary for the growth and activity of yeast, which is used in ethanol fermentation, and aeration helps maintain the oxygen supply to the yeast. Agitation helps mix the mixture, prevent sedimentation, and increase the contact between yeast and substrate, which improves the fermentation efficiency.
The fermentor used for making wine is typically a closed batch fermentor, also known as a tank or vat. This fermentor allows for precise control of temperature, aeration, and mixing, which are essential for optimizing the growth and activity of yeast during fermentation. The fermentor is typically made of stainless steel or other food-grade materials and is equipped with a cooling jacket and temperature probes to monitor and control the fermentation temperature. The fermentor also has an outlet for the fermentation product and an inlet for adding nutrients or other additives.