NAME:______DATE:______PERIOD:______

Fermentation and Root Beer

Root beer is a truly “American” drink. In colonial times, it was made by soaking the sasparilla root in water and adding it to a mixture of yeast, water and sugar. Yeast was used to make the drink alcoholic. The alcohol preserved the drink and made it last longer than plain water. Colonial people considered beverages fermented with yeast to be healthier than water, because people often become sick and died from contaminated water.

Yeast uses the process of alcoholic fermentation to break down glucose and create ATP. As a result, carbon dioxide and ethyl alcohol are also produced. This is the way that wine, beer and champagne are made.

In the late 1700’s scientists developed a way to create carbonated water or “fizzy” water without using yeast. It was considered to be a healthy alternative to drinking regular water. People experimented with flavoring the fizzy water, and soda was born.

In the early 1900s however, scientists discovered that safrole, a chemical found in

sassafras root, was a carcinogen (cancer-causing agent) and human consumption was banned. Now, a mixture of other herbs and spices makes up “root beer extract” which can be bought in stores. Root beer made commercially today does not use yeast and therefore is not alcoholic.

The alcoholic content of the beverage we will make is between 0.35 and 0.5 %, a very small amount compared to the 6% alcohol found in a 12-ounce beer. Persons with metabolic issues who cannot metabolize alcohol properly, those with a religious prohibition against alcohol, or those avoiding sugar should not consume this beverage.

You can use the following recipe to make root beer at home. You can change the amount of sugar and root beer extract you use, depending on your taste.

Ingredients:

1 twenty ounce bottle of room-temperature spring water

3-4 teaspoons of sugar

a small “pinch” of baker’s yeast

20 drops or a teaspoon of store-bought root beer extract (McCormick brand can be bought at Walmart)

Procedure: (Be sure your hands and measuring devices are clean because you will drink what you have made)

  1. Pour out the contents of the spring water bottle into a clean cup. You will use the empty bottle for mixing.
  2. Measure 3-4 teaspoons of sugar in the measuring cup. Use the funnel to pour it into the empty spring water bottle.
  3. Your teacher will add a small pinch of yeast to the bottle using the funnel.
  4. Add 2 ounces of the spring water to the bottle using the funnel. Cap it tightly and shake it to mix well. Be sure all the sugar dissolves.
  5. Let the bottle sit undisturbed for 10 minutes. While you are waiting, read the introduction and answer the questions.
  6. Add the spring water back to the bottle using the funnel. There should be at least 2-3 inches of empty space at the top of the bottle. DO NOT FILL THE BOTTLE TO THE TOP.
  7. Add 20 drops (1 teaspoon)of root beer extract using the pipette.
  8. Close tightly. Shake well.
  9. Label your bottle with your names.
  10. Leave the bottle in a warm, dark place overnight. You will know that it is ready to be refrigerated when the bottle feels swollen. DO NOT LEAVE THE BOTTLE IN A WARM DARK PLACE FOR MORE THAN TWENTY FOUR HOURS. DO NOT OPEN THE BOTTLE UNTIL YOU HAVE PLACED IT IN THE REFRIGERATOR.
  11. Place the bottle in the refrigerator for a minimum of 3-4 hours.
  12. When you are ready to drink it, DO NOT SHAKE THE BOTTLE. There will be sediment on the bottom of the bottle that you do not want to drink. Also, it will behave in the same way as a shaken bottle of soda.
  13. OPEN IT VERY CAREFULLY AND SLOWLY WHILE POINTING THE BOTTLE AWAY FROM YOUR FACE.
  14. Enjoy! (It tastes awesome poured over vanilla ice cream!)

Questions:

  1. What is the equation for alcoholic fermentation?
  1. How much ATP is produced by alcoholic fermentation?
  1. Are the yeast using oxygen during alcoholic fermentation?
  1. Why is this drink called root “beer?”
  2. What was the purpose of the room-temperature water? Why not hot or ice cold?
  1. What would happen if we left the yeast out of this recipe?
  1. What would happen if we left the sugar out of this recipe?
  1. What will happen inside the bottle overnight?
  1. Why was it important to leave space in the bottle?
  1. Why is the bottle put into the refrigerator?

Questions To Be Completed After You Taste the Root Beer:

  1. Do you notice any bubbles on the surface?
  1. What are bubbles made of?
  1. Does yours taste different or the same as store-bought root beer?
  1. If you thought it tasted different, what ingredients did we use that are not found in store bought root beer?
  1. What would happen if we allowed the bottle stay in a warm dark place for more than one night?
  1. Are the yeast still alive after being the refrigerator?

7. Write 5-10 original sentences on a separate piece of paper describing how your favorite store-bought soft drink is carbonated.

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