How does Yeast work?

Yeast is a one-celled, living fungus. There are many strains of yeast that live almost everywhere. Yeast feeds on carbohydrates that can be found in starch and sugar, which they convert to carbon dioxide and alcohol. This is a scientific process known as fermentation.

Yeast + Carbohydrates  = Alcohol + Carbon Dioxide

When the carbon dioxide is released by the yeast inside a bread dough, it gets trapped in the dough’s gluten network. This provides the desired rise and texture in the dough. The small amount of alcohol that is produced is evaporated during the baking.

Yeast is very sensitive to heat and moisture (see chart, Temperatures for yeast development). It prefers temperatures between 75° F-95° F (24° C-35° C). It remains dormant in temperatures below 34° F (2° C) and dies in temperatures excess of 138° F (59° C). Moisture activates the yeast cells, thus converting the carbohydrates in the dough into food.

Salt is very important in bread-making. Salt conditions the gluten, making it stronger and more elastic. Salt inhibits the growth of the yeast, controlling the rise. However, too much salt and the yeast is destroyed.