Reducing Agents (like L-cysteine) are a type of dough conditioner used to reduce mix time and improve extensibility. They are used in bread to increase bakery throughput and to adjust for flour variation and in a number of other yeast and chemically leavened applications. Read more about it in our Guide to reducing Agents.
Preferment is the general term for the sponge or brew step that is used at the start of many bread making processes to activate the yeast, contribute flavor and develop the dough. Read more about preferment’s in our guide to preferment’s.