Reader Ginny wants to know why bread doughs made with commercial yeast rise more aggressively than doughs made with wild yeast starters. Don’t they all contain more or less the same sort of yeast (i.e. Saccharomyces cerevisiae)?
Ginny, they do…more or less…and in therein lies the rub. For there’s a lot of variety in the tiny world of S. cerevisiae. The name in fact refers not to just a single fungus but to an entire family of fungi, all of which are genetically distinct from each other, and which perform differently in a bread dough. Commercial yeast manufacturers take care to select only the best and hardiest from among the strains, then tank grow them for uniformity and consistency.
The result is a sort of All-Star Team of yeast, which, when hydrated and mixed with flour, gives you a world class rise in the bread bowl. Home grown wild yeast starters are a little more like a team you might get playing pick-up ball in the park. A lot of eagerness and enthusiasm for sure, plus maybe a dad who nearly made it to the minor leagues before blowing his elbow out in ’94. But all told, a rather ragtag group that has more character than big league ability.
That said, given time and the proper encouragement, they generally get the job done. Thanks for the question, Ginny!