salt. Yeast activity is also strongly affected by
temperature: the cells grow and produce gas
most rapidly at about 95ºF/35ºC.
In addition to providing carbon dioxide gas
to inflate the dough, yeasts release a number
of chemicals that affect the dough
consistency. The overall effect is to
strengthen the gluten and improve its
elasticity.
Forms of Baker’s Yeast Commercial yeast is
sold to home and restaurant cooks in three
common forms, each a different genetic strain
of S. cerevisiae with different traits.
Cake or compressed yeast is a moist
block of fresh yeast cells, direct from the
fermentation vat. Its cells are alive, and
produce more leavening gas than the
other forms. Cake yeast is perishable,
must be kept refrigerated, and has a brief
shelf life of one to two weeks.
Active dry yeast, which was introduced