Ethanol Fermentation Lab Report

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Hypothesis If the type of yeast affects the rate of ethanol fermentation, then Non-expired Bread Machine will result in the fastest rate followed by Non-expired Quick Rise, Non-expired Traditional, and expired Quick Rise because Bread Machine has the smallest yeast granule size allowing it to dissolve faster, the pellet size of Quick Rise is smaller than Traditional suggesting that Traditional has a slower rate, and expired yeast loses its potency over time so it has the slowest rate of ethanol fermentation. Procedure The dependent variable is the rate of ethanol production. As sucrose reacts with the activated yeast, carbon dioxide gas will be produced. The dependent variable was measured by observing the amount of carbon dioxide gas produced. This was measured by inverting a graduated cylinder filled with water into a beaker also filled with water. A tube was inserted into the mouth of a graduated cylinder that was fully submerged in the beaker. The initial height of the water in the graduated cylinder was recorded in millilitres using the markers on the graduated cylinder. The other end of the tube was attached to the top of a test tube stopper. The ethanol fermentation occurred in a test tube. After five minutes, the test tube stopper connected to the tube was firmly secured to the top of that test tube, allowing the carbon dioxide gas to only travel through the tube into the submerged graduated cylinder. Gas bubbles were produced when the …show more content…

Type of Yeast Culture Trial Number Displacement of Water (mL) Average Rate of Ethanol Fermentation (mL/min) Initial Height of Water Final Height of Water Difference in Height Control: Non-expired Traditional 1 13.60 13.70 0.10 0.05 2 13.70 13.70

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