How to Kill Natural Yeast Before Fermentation

Decide if you prefer to brew with wild yeast or a yeast packet from the store. "Natural" yeast is a term often used to refer to wild yeast. Note that all yeast, even yeast that has been cultured, is natural. There is no such thing as artificial or fabricated yeast. The decision to use wild or cultured yeast relates to the amount of control you want over the fermentation process.

Purchase campden tablets if you choose not to use wild yeast. Campden tablets are a useful sterilizer for your brewing equipment but can also be used to kill wild yeast prior to fermentation. Note that if you are using a wine kit, you need to add yeast to get any fermentation. During processing all yeast organisms in the grape concentrate have already been removed. If making wine from fresh juice or grapes, you can kill wild yeast using campden tablets.

Create a "must" from fresh grapes. Follow the beginning steps of the wine-making process. Add water to the fermenter, and aerate the water. Sprinkle Bentonite into the water. Pour in fresh grape juice and stir. Add water to mixture until vat is filled (depends on the recipe and size of your equipment). At this point you have created a must.

Crush one campden tablet per gallon of liquid in the must. Turn the tablet into a fine, powdery substance to help the tablet dissolve more evenly throughout the must mixture. Do this 24 hours prior to pitching your wine yeast.

Continue with the fermentation process as you normally would.