NutritionFlavorMixingBoilingFryingBakingFood Safety
Not all living things in your food are bad. To make foods like bread, yogurt, and wine, you need live yeast and bacteria to carry out a chemical process called fermentation.
When yeast eat sugars, they release alcohol and carbon dioxide as by-products that you can use to make different foods. They turn barley or grape juice into beer or wine, and sugar into CO2 that helps your bread dough rise.
To make yogurt and many cheeses, you use bacteria for fermentation instead. Certain types of bacteria break down milk sugars into lactic acid, which not only creates flavor and texture but also helps prevent spoiling.

INGREDIENTS

• A packet of active
dry yeast
• Very warm water (~110˚F)
• Sugar
• A large balloon
• A small empty
water bottle

DIRECTIONS

Stretch the balloon by blowing it up and releasing several times.

Add the yeast and 2 tbsp. sugar to 1 cup water.
and stir.

Pour the mixture
into the bottle.

Attach the balloon
to the mouth of
the bottle.

Observe for
at least several
minutes.

WHAT'S COOKIN'

The yeast uses sugar as an energy source to produce carbon dioxide gas through fermentation. With nowhere to escape, the gas rises into the balloon. After several minutes, the balloon will stand up. Wait even longer and the balloon will slowly inflate.