======Yeast Fermentation and Temperature======


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====Summary====                   
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====Procedure====  
  - Prepare four boiling tubes or similar containers and label them for different temperature conditions.  
  - Add equal amounts of yeast to each tube.  
  - Prepare a warm sugar solution and use a pipette to add the same amount to each tube.  
  - Place each tube in water baths or environments set at different temperatures.  
  - Allow the yeast mixtures to react for a set amount of time (for example, 5-minute intervals over 20 minutes).  
  - Observe and record the amount of foam or gas produced in each tube at each time interval.  
  - Compare results to determine which temperature produced the greatest amount of carbon dioxide.



====Links==== 
Yeast fermentation Experiment 1- Temperature - Ysgol Eirias Technology Department: 
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Temperature and Fermentation in Bread Yeast - Samuel Holloway: 
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====Variations====
  * Use different types of sugar (glucose, sucrose, fructose) to compare fermentation rates.  
  * Test the effect of pH on yeast fermentation instead of temperature.  
  * Use balloons fitted over the tops of the tubes to measure gas volume more precisely.



====Safety Precautions====
  * Use caution with hot water baths to avoid burns.  
  * Dispose of yeast mixtures down the sink with plenty of water after the experiment.  
  * Ensure students aren't tempted to taste the resulting mixture with alcohol.




====Questions to Consider====
  * What is the relationship between temperature and yeast fermentation rate? (The rate increases with temperature up to an optimal point, then decreases as enzymes denature.)  
  * Why does the amount of foam or gas indicate the rate of fermentation? (Carbon dioxide is a product of yeast respiration, so more gas means faster fermentation.)  
  * What happens to yeast enzymes at very high temperatures? (They become denatured and stop functioning.)  
  * How could you make this experiment more accurate? (Use precise thermometers, control all variables, and repeat trials.)