Skip to main content

Yeast Experiment: Growth #2 – Is Yeast Alive?




  • Two glass measuring cups, 1-cup capacity each
  • Measuring spoon: teaspoon
  • Granulated sugar
  • Thermometer (to measure water temperature)
  • Warm water (110-115°F)
  • One packet of Red Star Active Dry Yeast (packet is ¼-ounce or 2 ¼ teaspoons)


  1. Make a yeast solution using 1/2 cup warm water (110° to 115°F), 1 teaspoon sugar and 1/4 ounce package of Active Dry Yeast.
  2. Each day, transfer 1 teaspoon of original yeast solution to a NEW solution of 1/2 cup warm water (110° to 115°F) and 1 teaspoon sugar.
  3. Make another sugar solution and add 1 teaspoon water daily.
  4. Keep a record of your progress for five (5) days.


  1. What do you observe happening to each of your containers?
  2. Does the yeast culture continue to multiply even though it becomes diluted by the daily transfer?

Review & Comments

Mathew Crow | Reply

Hi, I did an experiment with my daughter where we made a whole jar of starter, starting from a single granule of active yeast mixed with 1/8 teaspoon water and flour and feeding it double its weight each day until it was huge. It worked remarkably well. We wondered- approximately how many yeast cells does a single granule contain? Thank you!

Red Star Yeast | Reply

Hi Mathew – Sounds like a fun experiment! One standard packet (0.25oz/7g) contains billions of yeast cells, so one granule probably contains thousands of yeast cells. Naturally occurring yeast is also present in the flour and air, and since you only used 1 granule of yeast, most of the fermentation was from the wild yeast (and lactic acid bacteria).
I hope you will find this information helpful!

Donna marie | Reply

Never used yeast..bought RED STAR yesterday I want to make the Mother process for
Sour dough bread. Where do I start. Thanks dmc

Red Star Yeast | Reply

Hi Donna Marie – You can find our sourdough starter recipe here, and recipes to use the starter here. If you have further questions, we’d love to help! Contact us here.
Happy baking!

Leave a Reply