Monday, April 6, 2009

Yeast Experiments, Part 1

Yeast Week - Home Brewing

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.


Small glass measuring cup
Candy thermometer
Measuring spoons
1 package Champagne yeast (1 package yeast = 2 1/4 teaspoons)

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.

Champagne yeast on the left, baker's on the right.

Watching yeast ferment

This experiment was just for fun. It has a neat effect which was very cool to see.


2 empty soda bottles, washed no tops
2 latex balloons
2 rubber bands
glass measuring cup, 1-cup capacity
measuring spoons
water, room temperature

1. In each bottle put 2 teaspoons yeast, 1 teaspoon sugar and 1 cup water.

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.

The balloon on the left is the one without flour, the green one has the flour in it.

-FoodSub - Yeast Types:
-Red Star Brand Yeast:

1 comment:

Anonymous said...

my class loved it! it is exciting to see how the balloon grows!