Yeast Fermentation

Students investigate how different sugars (white sugar, brown sugar, and honey) affect the rate of yeast fermentation by measuring the amount of carbon dioxide produced, observed through balloon inflation.

1. Dissolve a packet of active dry yeast in warm water as directed on the package.
2. Label three bottles: “White Sugar,” “Brown Sugar,” and “Honey.” Add one tablespoon of the corresponding sugar to each bottle.
3. Pour equal amounts of the yeast solution into each bottle and mix gently.
4. Stretch a balloon over the opening of each bottle, securing it tightly with a rubber band if necessary.
5. Place the bottles in a warm location to encourage fermentation.
6. Observe and measure balloon circumference at regular intervals (e.g., every 30 minutes) for 1–2 hours.
7. Record results, compare the rates of inflation, and determine which sugar produced the most carbon dioxide.
8. Analyze whether the results support the hypothesis and consider further experiments.

Fermentation and Yeast Experiment - Beverly Biology:

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📄 Yeast Fermentation Experiment - Sarah McClelland: https://littlebinsforlittlehands.com/yeast-fermentation-lab/

• Test additional sweeteners such as artificial sugar substitutes, corn syrup, or fruit juice.
• Compare fermentation rates at different temperatures (cold, room temperature, warm).
• Change the amount of sugar added to see how concentration affects fermentation.

• Use warm water, not hot, to avoid killing the yeast.
• Do not taste or drink the yeast mixtures, as they are not safe for consumption.
• Handle glass bottles with care to prevent breakage.

• Why does the balloon inflate during fermentation? (The yeast consumes sugar and produces carbon dioxide gas, which fills the balloon.)
• Which type of sugar produced the most carbon dioxide, and why? (Sucrose in white sugar is readily broken down, while other sugars may take longer due to composition.)
• How is yeast fermentation important in everyday life? (It is used in baking bread, brewing beer, making wine, and producing biofuels.)
• What might happen if oxygen were present during fermentation? (The yeast would undergo aerobic respiration instead, producing more energy and less carbon dioxide.)