Some want to stop fermentation during the process of winemaking because they have tasted their wine and have decided that they like the amount of sweetness or bitterness that the wine has absorbed. Stopping the fermentation at a certain level preserves the level of sweetness. The wine would develop and become more bitter with each passing day. Wine will stop fermenting on their own but at this time the wine would become completely dry as the wine yeast turns them into alcohol. There is not a process to stop wine fermentation completely but we can indeed slow the wine fermentation process down significantly.
Use Sodium Bisulfite or Campden Tablets
The sulfites that are found in Sodium Bisulfite or Campden Tablets do not kill all the wine yeast to stop fermentation activity. But it significantly slows down the process.
Use Potassium Sorbate
Potassium Sorbate is another ingredient to stop the fermentation process. You simply add the Potassium Sorbate along with the sugar that you added to sweeten your wine. Potassium Sorbate does not kill the yeast at all but it rather makes the wine yeast sterile. In other words, it stops the yeast’s ability to reproduce.
Stop Fermentation with Cold Shock
This method does not tarnish the flavour or aroma potency for your wine. This method is simple to understand you just have to cool your wine to a temperature that will cause the yeast to stop its activity and precipitate on the bottom of the demijohn. You can start doing this by placing the wine in a very cold room or in the refrigerator for 3-5 days. It is essential that this wine stays above freezing point so please carefully monitor your wine. During this process, the fermentation will completely stop and the yeast will precipitate.
Stopping the Fermentation through Pasteurization
This is the most efficient method to kill wine yeast. Pasteurization is the process of heating your wine above 40 degrees Celcius.
Stopping the Fermentation with Alcohol
Adding more alcohol to your wine actually stops wine fermentation. When you reach a concentration of about 16% this is when fermenting stops. Racking the wine one more time before bottling might be necessary if the fermentation process does not stop.
Learn more about winemaking at Macedo U-Vin. Visit our facility we can help you get started even if you are a beginner.