Editing Holy Bread (section)

== Why It Is ==

Saccharomyces cerevisae is the scientific name for yeast. Most bakers are extremely familiar with this household fungus! Yeast is a single-celled organism, whereas you and I are composed of billions of cells of hundreds of different types. We buy this fungus at the grocery aisle, and it looks like this (show a spoonful). All organisms need the proper conditions – warmth and food, so we’ve provided our yeast with sugar and 40 degrees C (about 105 degrees F).

Just like humans and other animals, yeast breathe in oxygen and breathe out carbon dioxide. This point is first demonstrated by blowing through a straw into indicator solution located in the Erlenmeyer flask. The indicator solution will turn from blue-green to light green to yellow due to the formation of carbonic acid when carbon dioxide goes into solution. A chemical reaction takes place in the receiving flask as a result of the yeast “breathing” just like we do, releasing carbon dioxide. We’ve trapped the gas, and it will travel through the tubing into the other chamber. Over the next 10 to 15 minutes, gas bubbles will emerge in the pH indicator solution. The solution will change color from blue-green to yellow-orange as carbon dioxide produced by the yeast dissolves in the water to make carbonic acid.

Yeast are just one of the billions of microorganisms that we employ every day in ways to keep our lives running smoothly. Whether we realize it or not, we are dependent on the bacteria in our intestines to digest our food, the fungi in our mucous membranes to keep out invading pathogens, and billions of other uses that we rarely think of. It is our duty to preserve the micro on behalf of the macro.

Think about it. All of this, just from a piece of bread!