To halt fermentation, one option is to add potassium sorbate to the wine. This compound acts as a yeast inhibitor, preventing the yeast from reproducing and continuing the fermentation process. It is commonly used in winemaking to stabilize wines and prevent re-fermentation in the bottle.
When using potassium sorbate, it is recommended to add 1/2 teaspoon per gallon (4 liters) of wine. This dosage is generally effective in stopping fermentation and preventing any residual sugar from being fermented further. It is important to note that potassium sorbate does not kill yeast cells, so it is best used when fermentation is almost complete or has reached the desired level of sweetness.
Another method to stop fermentation is through fortification, particularly for wines that are intended to be Port-style or aperitifs. This involves the addition of a distilled spirit, typically brandy, to raise the alcohol content. The higher alcohol concentration creates an environment that is unfavourable for yeast growth, effectively stopping fermentation. The added spirit also contributes to the flavor profile and character of the fortified wine.
Fortification can be a creative and exciting technique to control fermentation and add complexity to the wine. It allows winemakers to balance the sweetness and alcohol level, resulting in a fortified wine with unique characteristics. It is important to consider the desired style and balance when deciding whether to fortify a wine.
In my own experiences as a brewer and sommelier, I have used both potassium sorbate and fortification techniques to halt fermentation in different situations. For wines that require a touch of residual sweetness, potassium sorbate has been a reliable tool to prevent further fermentation while maintaining the desired level of sweetness. This is particularly useful when making off-dry or semi-sweet wines.
On the other hand, fortification has been a fascinating technique to explore when crafting fortified wines. The addition of brandy not only stops fermentation but also imparts unique flavors and aromas, enhancing the overall complexity of the wine. It is a method I have used when making fortified dessert wines or fortified aperitifs, and it has always yielded intriguing results.
In summary, to stop fermentation in winemaking, potassium sorbate can be added at a rate of 1/2 teaspoon per gallon (4 liters) of wine. This yeast inhibitor prevents further fermentation by stopping yeast reproduction. Alternatively, fortification with distilled spirits, such as brandy, can be employed to raise the alcohol content and create an unfavorable environment for yeast growth. Both methods offer winemakers the opportunity to control the fermentation process and achieve the desired style and sweetness in their wines.