Root Beer Production

Introduction:

In this laboratory you will be demonstrating the action of yeast on a mixture of sugar, water and flavorings through both aerobic and anaerobic respiration. Yeast are microbes that will break down sugar into water and carbon dioxide--the latter causing the root beer to become carbonated. The oxygen present will eventually be depleted, causing the yeast to revert to anaerobic respiration. Be sure to follow aseptic technique and use only food-grade containers for this experiment. You will be responsible for making a control sample following the formula below and at least one other batch of root beer in which you have changed only one factor. You need to hypothesize what differences your experimental group will have as compared to your control. You must submit a proposal on what your experimental group(s) will entail before beginning this laboratory work.

Materials:

Bottles--washed and sterilized

Wine corks or caps and crowns

Stirring spoon

Large (20 liter or 5 gallon) enamel kettle or pot--DO NOT USE ALUMINUM!!!

*59 mL Schillings root beer concentrate

*2.27 kg sucrose (table sugar)

*19 liters chlorine-free water

*Containers to measure out needed volumes of materials--your choice--see procedures

*9.5 g yeast dissolved in 236 mL warm water

*see caution 2 below

Cautions:

1. Wash hands thoroughly with antibacterial soap and water before and after completing each step of the laboratory.
2. Alter the volumes and measures (by using proportions) to best suit your needs.
3. Wear goggles and laboratory apron.

Control Group Procedure:

Day 1

1. Make sure all materials, equipment, and your hands are as clean as possible. Wash hands before handling any materials.
2. Place sucrose and root beer extract into kettle.
3. Gradually add chlorine-free water
4. Add yeast/warm water mixture and stir well.
5. Immediately place mixture in clean/sterile bottles, leaving approximately a 5 cm airspace at the top.
6. Tightly cork or seal the bottles and place them on their sides in a warm (25-30 degrees celsius) location.

Day 2

• Record observations

Day 3

• Record observations

Day 4

• Once refrigerated, your root beer should be ready for consumption

Reference:

Nancy Heitel, et. al., "Production of Home Brewed Root Beer," Mankato State University, Mankato, MN, 1988

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