Capture Wild Yeast

In a previous lesson, you learned that yeast needs warm water and food to awaken and grow. In that experiment, we used dehydrated dormant yeast from the grocery store. Before grocery yeast was available, bakers used wild yeast. Remember that yeast is widely dispersed throughout our environment. Some yeast is good for baking; some isn’t.

How do you capture your own wild yeast? Here’s one simple way.

Activity: Buy organic grapes. Or pick wild grapes (even more fun!). Crush the grapes with the back of a spoon. Place in a plastic container in a sunny spot and cover with plastic wrap. After a a day, or even a couple of hours if the conditions are right, it should start to foam. That means yeast is actively growing and exhaling carbon dioxide gas.


  1. Where is the water in this experiment? Remember yeast needs water to grow.
  2. Why do you need to put the plastic container in a sunny place?
  3. What is the food provided in your experiment?
  4. Why do you use organic grapes?
  5. Where did the yeast come from? (the grape skins)