If you’ve ever looked into bread baking, you’ve probably run into a wall of confusing vocabulary—starters, levains, poolish, and bigas. Think of all of these simply as preferments. A preferment is just a head-start mix of flour, water, and yeast that ferments before it gets added to your final dough. We use them to build complex, mature flavors, improve dough structure, and make our bread last longer.
Here is a breakdown to help you navigate the world of baking preferments without the confusion.
🌿 The Sourdough Loop: Working with Wild Yeast
Unlike standard baking, true sourdough relies entirely on wild yeast and beneficial bacteria captured right from our environment. Instead of running on separate jars, the sourdough process is a continuous daily cycle.
1. The Mother (The Starter)
This is your permanent culture line, but it doesn’t live in a separate, stagnant jar. It is simply the portion of active culture that you carry over from the previous day to kickstart your next build.
- Home Baker Tip: If you don’t bake every day, you can keep this Mother culture on “hold” in the refrigerator to pause its activity until you are ready to bake again.
2. The Levain
Every day, you take that saved Mother culture and feed the entire thing together to build the grand total volume needed for the next day’s bakes. This active, fully fed mixture is your levain. It ferments and peaks right on schedule for your mixing time. When it is perfectly “ready to go,” you save a small portion of it to become tomorrow’s starting Mother, use the rest in your current baking recipes, and any remaining surplus becomes your discard.
3. Sourdough Discard
This is the extra, unfed starter left over from the daily loop. While bakers try to mix exactly what is needed for the day’s bread and the next day’s Mother, a little extra surplus is common. This extra amount can either be fed to turn into more levain or set aside as discard. We try to keep discard to an absolute minimum because it is highly difficult to dispose of.
- The Plumbing Rule: Never put starter or discard down your sink. It acts like instant cement inside pipes and will completely destroy your plumbing. Keep your surplus in a jar in the fridge to use for sourdough crackers, pancakes, or waffles!
4. Scrapings
This is the residual starter left stuck to the bottom and sides of your containers. Instead of washing them down the drain or feeding them (which just creates an endless mountain of unnecessary excess levain), let them completely air dry. Once dry, they become brittle, flake off effortlessly, and can be scraped straight into your regular trash bin.
🍞 Preferments & The Yeast Family
These preferments are mixed a few hours or even a day in advance to expand a bread’s character. They can be created using standard store-bought commercial baker’s yeast or a natural sourdough starter baseline depending on the flavor you want to achieve.
- Poolish: A wet, liquid preferment made with equal parts flour and water by weight (100% hydration), giving it the texture of a runny, bubbly pancake batter. A poolish can be yeast or sourdough based, and its primary purpose is to impart an incredible, deep flavor. It also adds a subtle sweetness and makes dough incredibly stretchy—perfect for baguettes, crispy focaccia, or light pizza crusts.
- Biga: A stiff, dry preferment. This is an Italian style made with much less water (around 50–60% hydration), feeling like a dense, shaggy dough ball that you actually have to knead. It creates an open, airy internal crumb with a rich chew—ideal for rustic loaves like ciabatta.
- Pâte Fermentée (Old Dough): Literally translating to “fermented dough,” this is simply a piece of leftover raw dough saved from yesterday’s batch of bread. It is wrapped, refrigerated overnight, and mixed directly into today’s fresh batch to give a simple, daily white loaf an instant “aged” depth of flavor and beautiful crust color.
⏱️ Quick Preferment Cheat Sheet
| Preferment / Term | Yeast Source | Hydration / Texture | Best Used For / Key Traits |
|---|---|---|---|
| The Mother / Starter | Wild Yeast & Bacteria | Continuous active culture | Carried over daily to loop into the next batch build. |
| Levain | Wild Yeast (from Mother) | Varies by recipe | Peaked, fully fed mixture ready for your current day’s recipe. |
| Sourdough Discard | Unfed Wild Yeast | Pourable, acidic batter | Surplus from the loop; save in the fridge for crackers or waffles. |
| Scrapings | Unfed Wild Yeast | Air-dried residue | Left to dry in the container so it can be safely scraped into the trash. |
| Poolish | Yeast or Sourdough | Runny / 100% hydration | Imparting excellent flavor; great for baguettes and stretchy doughs. |
| Biga | Commercial Yeast | Stiff / 50-60% hydration | Ciabatta, rustic Italian loaves, and structured, chewy crusts. |
| Pâte Fermentée | Commercial (from yesterday) | Fully mixed dough ball | Adding instant “mature” flavor to a fresh batch of daily white bread. |










