As an expert sommelier and brewer, I can tell you that the temperature at which fermentation stops can vary depending on the type of fermentation and the specific conditions. In general, fermentation is a complex process that involves the conversion of sugars into alcohol and carbon dioxide by yeast or bacteria. This process is highly sensitive to temperature, and different organisms have different temperature ranges in which they thrive.
For wine fermentation, the ideal temperature range is typically between 20°C to 32°C (68°F to 89.6°F). Within this range, yeast activity is optimal, leading to the desired fermentation process. At lower temperatures, fermentation may proceed too slowly, while at higher temperatures, it may occur too rapidly and result in the loss of desirable flavors and aromas.
In the specific case of red wine fermentation, a slightly higher temperature range is often preferred. This is because higher temperatures can help extract more color and tannins from the grape skins, resulting in a more robust and structured wine. However, there is a limit to how high the temperature can go before it becomes detrimental to the fermentation process.
Once the temperature reaches around 35°C to 38°C (95°F to 100.4°F), the fermentation can be at risk of being aborted. At these elevated temperatures, the yeast cells can become stressed and may even die off, leading to a halt in fermentation. This can have negative impacts on the wine, such as incomplete sugar conversion and off-flavors.
It is important to note that different yeast strains have different temperature tolerances, and some may be more resilient to higher temperatures than others. Additionally, the duration of fermentation can also affect the temperature tolerance, as yeast activity can generate heat during the process.
To ensure a successful fermentation and avoid the risk of it being prematurely stopped, winemakers carefully monitor and control the temperature throughout the process. This can be achieved through the use of temperature-controlled fermentation vessels or by employing cooling or heating methods as needed.
In my personal experience, I have encountered situations where the fermentation temperature went beyond the desired range, either due to equipment malfunction or unexpected weather conditions. In these instances, it was crucial to take immediate action to bring the temperature back within the optimal range. This could involve adjusting the ambient temperature of the fermentation area, using cooling devices, or employing other techniques to cool down the fermenting wine.
The temperature at which fermentation stops can vary depending on the specific conditions and organisms involved. For red wine fermentation, the ideal temperature range is typically between 20°C to 32°C (68°F to 89.6°F). However, once the temperature exceeds around 35°C to 38°C (95°F to 100.4°F), there is a risk of fermentation being aborted. Monitoring and controlling the temperature throughout the fermentation process is crucial to achieving the desired outcomes in winemaking.