Do you know the difference?

Yeast is a leavening agent, which means it is used in a baked product to increase volume and produce shape and texture. Yeast comes in fresh form as well as two types of dry forms:

1. Fresh yeast - (also called compressed yeast) is moist and perishable and is preferred by professional bakers
2. Active dry yeast - a dry, granular form of yeast that must be rehydrated in warm water before using it
3. Instant dry yeast - (also called rapid-rise or quick-rise yeast) also a dry, granular form of yeast, but does not have to be dissolved in water before use. It can be added in its dry form because it absorbs water much more quickly than regular dry yeast.

Because yeast is a living organism, it is sensitive to temperatures. The ideal temperature in which yeast grows (for proofing bread) is between 70-90 degrees F. If yeast is exposed to temperatures above 140 degrees F, it is killed and it's leavening reactions cease.