How to Grow Yeast Using Yeast Extract
- 1). Pour one tsp. of yeast extract into a bowl.
- 2). Pour one tbsp. of sugar into the bowl with the yeast.
- 3). Add two tsp. of warm water into the bowl, and mix well with a spoon.
- 4). Soak the tip of a cotton swab into the mixture, and then rub the soaked tip onto an agar-coated petri dish. Agar is a microbial-free gelatinous substance that detects bacteria. You can purchase petri dishes precoated in agar. If you have a dish that is not precoated, combine four tbsp. of pure agar powder --- available at any school supply store --- in a bowl with four tbsp. of warm water. Stir well and pour the mixture into the petri dish. Wait 30 minutes for the agar to set.
- 5). Place the lid onto the petri dish, and place the dish in a dark area for three days. After the allotted time, yeast grows inside the dish.
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