Investigating Alcoholic Fermentation and the Affects of Yeast on Dough

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Biology Lab Report

Investigating Alcoholic Fermentation and the Affects of Yeast on Dough

Aim: The aim was simply to investigate whether or not yeast had any affect on causing dough to rise when baked and to experiment with alcoholic fermentation eg. to see if it gave off carbon dioxide.

Introduction: Following a few weeks of fermentation theory, groups of three to four were assigned and told to conduct a series of experiments involving the affects of fermentation. My group consisted of myself, Won Jin, Brendan and Sun-Ho and we chose to investigate alcoholic fermentation and the affects of yeast on dough, more specifically to see if yeast caused the dough to rise in anyway. We followed the instructions in our biology textbook on page 129.

Hypothesis: According to what I've learned, I would expect that the yeast does indeed cause the dough to rise due to the carbon dioxide gas given off by the yeast. For our alcoholic investigation, I can safely assume that carbon dioxide will be given off as the formula for anaerobically respiration in alcoholic fermentation for turning glucose into alcohol is [ Glucose -> Alcohol + Carbon Dioxide + Energy ] so obviously Carbon Dioxide is a part of this. Also I assume that the fermentation will give off heat and the sugar will probably be turned into alcohol.

Materials:ca. 100 g flour
10 per cent solution Glucose
Liquid Paraffin
Four Test Tubes
Lime Water (Used as an indicator)

Practical: Our first experiment was to see if yeast impacted dough in anyway and to do this we brought in supplies such as flour and yeast. We followed the instructions and made three groups of dough. For each group we added 50 g of flour and added a little bit of water while mixing it. Due to my lack of "kitchen skills" I had to throw away my first two attempts, as they had gotten too sticky. But like they say, third time's the charm and we finally made suitable dough.

We mixed warm water and yeast...
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