We have been doing a few yeast experiments this week, some of which are still in the process of being completed. The major part of this week was making our own root beer, which will be covered in another post. Here we have two small experiments that we did as well.
Testing Yeast Experiment.
Before we tried the root beer experiments, we found that the yeast we were going to use (it was champagne yeast from a kit) had expired in 2006, so the first thing we did was to test to see if it was still good with this experiment.
Materials:
Small glass measuring cup
Candy thermometer
Measuring spoons
Water
1 package Champagne yeast (1 package yeast = 2 1/4 teaspoons)
Sugar
1. Pour 1/4 cup water into a small glass measuring cup for liquids. Heat in microwave 20 seconds on high. Stir. Measure temperature. Water should be between 100 and 105 degrees F. If too cool, heat for 10 seconds. If too hot, add some cool water.
2. Add ½ teaspoon yeast and a pinch of sugar. Stir and let sit for 5 to 10 minutes, until the sugar and yeast dissolve. If a foamy layer forms on the surface, the yeast is still active.
3. If still active, seal the package and put in refrigerator for later. If not, throw it out.
The result was that the champagne yeast was too old to be used. We tested this along with regular baker's yeast and decided to use that instead.
Watching yeast ferment
This experiment was just for fun. It has a neat effect which was very cool to see.
Materials:
2 empty soda bottles, washed no tops
2 latex balloons
2 rubber bands
glass measuring cup, 1-cup capacity
measuring spoons
clock
flour
sugar
water, room temperature
yeast
2. In one soda bottle, add 2 tablespoons flour. Mark this bottle.
3. Secure a balloon on top of each soda bottle with a rubber band.
Links
-FoodSub - Yeast Types: http://www.foodsubs.com/LeavenYeast.html
-Red Star Brand Yeast: http://www.lesaffreyeastcorp.com/SoY/story_2.html
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1 comment:
my class loved it! it is exciting to see how the balloon grows!
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