This experiment outlines the process for making homemade wine using yeast fermentation. Yeast is added to fruit juice and sugar water, which are then sealed and allowed to ferment for a month, producing alcohol. Lemon juice is added to help regulate the acidity level and pH of the wine, promoting a favorable environment for the yeast to ferment the sugars into alcohol.

1. Experiment/Project: Making Home/Lab-made Wine
Biotechnology is the production of materials using biological organisms or their processes. In this
experiment, the cellular respiration of yeast is utilized in a process known as fermentation to produce
carbon dioxide and alcohol.
WARNING: It is important to follow the directions as closely as possible. Nobody wants to drink
wine contaminated with chemicals or harmful bacteria. To ensure this, all materials will be
provided by each group.
Materials and Apparatus:
1-1.5L fresh 100% fruit juice or puree
1-1.5 cups sugar
Juice of 2 lemons
Distilled water
Yeast
1.5-2L container
Kitchen funnel
Kitchen plastic wrap
Rubber bands
Cloths
Closed bag
Procedure:
1. Sterilize all equipment (including the closed bag and the containers for sugar, lemon juice, etc.)
by soaking in a solution of bleach and water for 20 minutes. Rinse thoroughly with warm water
to get rid of the chlorine smell as much as possible. Store all equipment in a clean sterilized
closed bag, and bring to the laboratory. Closed bag is important to minimize exposure to air,
which could contain bacteria.
2. Lay down a clean sterilized cloth on the laboratory table. Do not lay any equipment on the table
itself as the table may be contaminated with chemicals.
3. Turn on the Bunsen burner. Remember to wash your hands afterwards as the Bunsen burner
may be contaminated with chemicals. Heat kills bacteria, so a nearby Bunsen burner minimizes
the amount of bacteria in the air that could contaminate the wine.
4. Wash your hands and your gloves to remove any contaminating bacteria.
5. Mix sugar with just enough distilled water (water that is not distilled may contain bacteria) to
dissolve the sugar.
6. Pour the sugar solution into the clean sterilized 1.5-2L container using a clean sterilized funnel.
7. Add the fruit juice and the lemon juice into the clean sterilized 1.5-2L container. Stir with a
clean sterilized long wooden or metal stick.
8. Put a piece of kitchen plastic wrap on top, and secure with a clean sterilized rubber band. Store
at room temperature in the dark overnight.
9. The next day, take off the rubber band, and add a spoonful of yeast into the 1.5-2L container.
Again, the Bunsen burner must be on. Read the packet of yeast for any additional instructions;
some yeast may need to be activated before use. Yeast that does not need to be activated is
preferred.
10. Replace the kitchen plastic wrap with a new piece, and secure with a rubber band. Store in a
warm and dark place for a month to ferment.
11. Light-colored, sweet fruit juices are preferred because more sugar means more alcohol
produced, and the light color will allow the sediment to be clearly seen. After one month, pour
into a glass/cup, and enjoy. Be careful not to pour the sediment.
Question: What is the purpose of adding lemon juice? (You may do some research beforehand).