: The yeast acclimates to the wort, taking up essential nutrients like oxygen and amino acids to prepare for growth.
: As sugar levels decline, yeast activity slows. During this time, healthy yeast can "clean up" undesirable byproducts like diacetyl, which can otherwise cause off-flavors.
: Fermentation completes, and the yeast clumps together (flocculates) and settles to the bottom, allowing the beer to clarify. Essential Brewing Resources
Fermentation typically unfolds in a consistent biological progression: