Final answer:
The term used for fortifying wine during fermentation is simply called fortification, which involves adding distilled spirits to the wine to increase alcohol content and halt fermentation.
Step-by-step explanation:
The term used for fortifying wine during fermentation is fortification. This process involves adding a distilled spirit, typically brandy, to the wine in order to increase the alcohol content. The fortification of wine is usually done to enhance its flavor, to stabilize it for long-term storage, and to prevent fermentation from continuing to a point where all sugars are converted into alcohol, resulting in an overly dry wine. Since yeasts are responsible for converting sugars into ethanol and carbon dioxide, the addition of alcohol in the form of spirits kills or deactivates the yeast, thus halting the fermentation process.
It is noteworthy to mention that fermentation, as a general process, is a form of anaerobic cellular respiration where microorganisms like yeast convert sugars into ethanol and CO2. In the context of fermentation tanks, they are often equipped with valves to release the pressure build-up from CO2 production.