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Yeast Fermentation Lab Report

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by Chris Alleman on 12 November 2012

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Transcript of Yeast Fermentation Lab Report

Chris Alleman, Rachel Poulsen, Spencer Koelsch, Jade Jones
Class Period 6
Pre AP Biology Water Temperature and Its Effect on the Fermentation of Yeast Conclusion (Rachel) In this experiment, we tried to answer the question of whether the temperature of water affects the production of CO2 in a yeast/sugar solution. Our group believed that it would have an affect, and that as the temperature of the water increased, so would the production of CO2. Based on our data, this was correct, as the water with the lowest temperature produced no CO2, or at the least, so little it could not be measured, and the hottest water produced the most by far.
If this experiment were to be performed again, it would be more accurate if more than a single trial were done for every temperature. The single test idea has a large possibility for error. There might also have been a couple errors with letting the pipette touch the bottom of the cup for too long, or having it wobble around. In a better experiment, the pipette's position would not be dependent on a human's ability to hold it still.
This experiment shows that water temperature has a direct correlation with yeast fermentation. This can be applied in many areas, such as baking or beer production, as both involve the fermentation of yeast. As with all experiments, new questions come from answers. One might wonder at what temperature the solution would produce the largest amount of carbon dioxide. Perhaps they could wonder the temperature at which the yeast solution is unable to ferment at all. Another question could be that of the temperature best suited for baking different types of food. This experiment has many practical applications. Introduction Background information
Research Question
Variables
Independent
Dependent
Constants
If…and…then statement (hotter the water, the more CO2) Experimental Plan 1.Mass 3.0 g of dry yeast and place in a Styrofoam cup.
2.Adjust the temperature of the water to approximately 35 degrees Celsius.
3.Using a 50 ml beaker or a graduated cylinder, measure 50 mL of the water and add it to the 3.0 g of dry yeast in the Styrofoam cup.
4.Add 1 drop of food coloring to the yeast and water mixture.
5.Stir for 5 minutes to completely hydrate the yeast. Gently break up globs of yeast. Scrape yeast that sticks to the side back into the liquid.
6.Weigh out 2.5 g of sucrose.
7.Add the 2.5 g of sucrose to the yeast and stir for 30 seconds.
8.Place the end of a closed graduated pipet into a Styrofoam cup to collect spillage.
9.Pour approximately 20 mL of the colored sugar water- yeast suspension through the funnel into the pipet. Remove the pipet and pour the remaining colored sugar- yeast suspension into the Styrofoam cup.
10.Invert the graduated pipet into the Styrofoam cup. Then quickly record the height of the fluid in the graduated cylinder and start the timer.
11.Hold the pipet steady, keeping it in the same place within the cup for 5 minutes.
12.Repeat steps 1 through 12 for 20 degree C and 50 degree C water.
13.Record all results. Observations:
The 24 degree water did not produce any measurable CO2, presumably because the water temperature is too cold for the yeast to ferment.
The 35 degree water, the control produced 1.5 mL of CO2, considerably more than the 0 produced by yeast in 24 degree water
The yeast in 44 degree celsius water produced nearly double that of the 35 degree water
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