Yeast Fermentation Lab

Purpose: The purpose of this lab is to find the ideal conditions for carbon dioxide production in yeast. Determining the ideal conditions for carbon dioxide production would help Jim Baker bake his bread as fluffy as possible in a short amount of time.

Background: Yeast are single-celled fungi. Yeast cells use an anaerobic process called alcoholic fermentation to produce energy in the form of ATP. Not only does this process convert glucose into ATP, but it also breaks down the glucose molecules into ethanol and carbon dioxide. Organisms obtain the energy they need from food. Yeast cells use sugars, such as glucose, as a food source. However, because glucose cannot be used directly by organisms, glucose molecules have to go through the process

To help maximize Mr. Baker’s bread rising process, my group decided to test .5, 1.5 and 2.5 grams of sucrose with 35 ℃ water. We also tested .5 grams of sucrose in 30 ℃, 35 ℃ and 40℃ water. Activity 2 Hypothesis: My group believed that 2.5 grams of sucrose in 35℃ water would produce the most foam.

Procedure:

The procedure my group used was :

Measure six groups of four grams of yeast, four groups of .5 grams of sucrose, one group of 1.5 grams and one group of 2.5 grams of sucrose.

Add 80 ml of 35℃ water in three different cups. To prevent the temperature of the water from decreasing, instantly pour in four grams of yeast. In one cup, add .5 grams of sucrose, 1.5 in another, and 2.5 grams in the last cup. Stir the water for a minute, making sure to get rid of any clumps.

After waiting for 20 minutes, measure the ending temperature and the depth of the foam in each cup.

Next, measure 30℃, 35℃, and 40℃ of water (80 mL of each). As soon as you reach each temperature, add four grams of yeast and .5 grams of sucrose. Stir the water for a minute. Once you get rid of any clumps, let each mixture sit for 20