Yeast Ferment

This old-fashioned potato yeast ferment is a baker’s shortcut that dates back generations. Potato water is loaded with starch that feeds the yeast aggressively, giving you a faster, more vigorous rise than plain water ever could.

The mashed potato stirred into the liquid adds even more starch and gives finished bread a softer, more tender crumb. There’s a reason potato bread has that distinctive pillowy texture, and this ferment is the foundation.

Make a quart, use what you need for your current bake, and store the rest in the fridge for several days. Having a ready-to-go ferment on hand means fresh bread is always just a few steps closer.

Pro Tips

• Cool the potato water to lukewarm before adding the yeast. Hot liquid kills yeast on contact and you’ll get zero rise.
• Save every drop of that potato cooking water. The starch dissolved in it is the whole point of this technique.
• The ferment should bubble and smell yeasty within 30 minutes. If nothing happens, your yeast may be expired.
• Stir the ferment before measuring from the stored batch. The potato starch settles to the bottom.

Variations

• Add a tablespoon of honey instead of sugar for a slightly different flavor profile.
• Use sweet potato for a ferment that adds a hint of color and sweetness to bread dough.
• Double the batch and freeze portions in ice cube trays for quick use later.