Wine is made from fermenting fruit juices through the addition of yeast, which converts the natural sugars into alcohol and emits carbon dioxide. Once the wine has fully fermented, wine stabilizer is added to completely end fermentation, thereby preventing secondary fermentation, which can affect the quality of the wine and prevent build-up of carbon dioxide gas, from taking place. Wine stabilizer also allows the winemaker to add sweetness to a finished wine. Potassium sorbate (Sorbistat K), in conjunction with potassium or sodium metabisulfite (Campden tablets), are the most commonly used additives to achieve this. These additives are readily available from home brew supplies stores.
Prepare your wine according to whichever recipe you are following. Leave the wine to ferment according to the instructions and until there is no further fermentation evident from observation.
Add one crushed Campden tablet per gallon to the wine. Camden tablets contain sulfite either as sodium or potassium metabisulfite. The tablets react with the wine to form sulphur dioxide gas that dissolves in the wine and is released into the air. Yeast is intolerant of sulfites.
Measure 1/4 teaspoon of potassium sorbate per gallon of wine if you do not intend to further sweeten your wine before bottling. Use 1/2 teaspoon per gallon if you are adding further sweetening.
Add the potassium sorbate to a cup of the wine and stir until it dissolves. Pour the wine and potassium sorbate solution back into your fermented wine and stir the entire batch thoroughly. Leave the stabilized wine for 10 days before bottling.