Fermentation
Introduction
Beer and wine are produced by the fermentation of glucose by yeast. In this experiment, a glucose solution is left to ferment. The resulting mixture, is then tested for the presence of any fermentation products.
Apparatus
Boiling tube, Conical Flask, Delivery tube for boiling tube & conical flask, Yeast Powder, Lime Water, 10% Glucose solution
What to record
What was seen to happen to the limewater.
What to do
Lesson 1
- Put 5 g of glucose in the flask and dissolve it in 50 cm3 of warm water. (Becomes 10% Glucose Solution)
- Add 1 g of yeast to the glucose solution and plug the top with delivery tube.
- Wait 20 min while fermentation takes place.
- Remove the delivery tube and pour the invisible gas from the flask into the boiling tube with lime water. Take care not to pour any of the liquid as well.
- Gently swirl the lime water round the tube and observe what happens.
Lesson 2
- Note the smell of the solution.
Safety
Wear eye protection. Do not taste the product.
Questions
- What gas is present in the flask after fermentation?
- Yeast contains a chemical called zymase, which is an enzyme. Complete the word equation for fermentation.
zymase
Glucose ------------> +
