Bulk Fermentation in Sourdough Artisan Bread

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Bulk fermentation is a crucial step in the process of making sourdough artisan bread. This period of rest and fermentation is essential for achieving the distinctive flavor and texture associated with sourdough bread. Proper management of bulk fermentation in sourdough artisan bread is key to producing high-quality, delicious sourdough loaves.

What is Fermentation?

Fermentation refers to the time the wild yeast and bacteria are fermenting the dough: by consuming the microorganisms in the flour and creating gasses that raise dough. Fermentation, which typically lasts many hours, allows the yeast and bacteria in the sourdough starter to metabolize the flour and water mixture, developing the bread’s flavor, texture, and structure. The dough undergoes significant changes, including increased volume, air pockets, and a more elastic consistency. This is a long process for sourdough because the entire loaf of bread needs to go through the fermentation process in order for the dough to rise. As soon as the sourdough starter or levain is mixed with fresh flour and water, the fermentation cycle begins.

What is Bulk Fermentation?

Bulk fermentation refers to the time that the dough is just mixed up until it is shaped. It is when the “bulk” of the dough is together as one mass of dough and ferments together. For most sourdough artisan bread recipes, a bulk fermentation takes around 4-5 hours if the temperature of the dough is 78-80 degrees F. I use a bread proofer to help keep the dough temperature consistent.

Characteristics of Bulk Fermentation

  • Dough is mixed with sourdough starter or levain
  • Dough is strengthened through a series of stretch-and-folds or coil folds
  • Dough sits at 78-80 degrees F for 4-5 hours
  • Dough has bubbles around the edges, has increased 30-40% in size and is domed when it is ready to be shaped

After the dough has undergone a room temperature (78-80 degrees F) bulk fermentation, you have a decision to make: You can either shape the dough immediately and let it rise again OR shape the dough and place it in the refrigerator for a cold fermentation.

What is Cold Fermentation?

I almost ALWAYS choose a cold fermentation. A cold fermentation is the process of retarding the dough in the refrigerator overnight or for 10-48 hours until you are ready to bake it. The cold refrigeration significantly slows down the fermentation of the dough, allowing you to choose when you want to bake it.

Benefits of Cold Fermentation

  • Dough develops more flavor (not necessarily sour but more complex flavor)
  • Dough is easier to score. Cold dough is much easier to score than room temperature dough, leading to a better oven spring.
  • Dough is less likely to over-prove. You can bake the sourdough anytime from 10-48 hours later–I’ve even pushed it up to 3 days and it’s turned out well.
  • Cold Fermentation allows you to plan your bake–In a world where sourdough takes a lot of time, being able to pop the shaped loaf in the refrigerator and then choose when you want to bake it is a game changer. No waiting around all day for your bread to rise; choose when you want to bake it – within about a 3 day window.

Can I cold ferment dough that is not shaped?

Yes. After the initial bulk fermentation, you can stick the entire container of dough into the refrigerator for a cold bulk fermentation. Let it sit for 10-48 hours before shaping it. You do need to be more careful when you shape the dough to not deflate it. I prefer shaping room temperature dough, so I always shape my sourdough artisan bread before the cold fermentation. Then I only have to clean up once too!

Can you use cold fermentation on any bread dough?

Yes. You can refrigerate any bread dough to give the yeast a little “pause.” For bread made with sourdough that is NOT artisan bread, I often use a cold bulk fermentation before shaping the dough. Non-artisan bread is not baked in a dutch oven and doesn’t need the steam to encourage a rise. It does need to be shaped and then rise again until light and puffy before baking (I see you sourdough cinnamon rolls). Artisan bread, however can be baked straight from the refrigerator to the dutch oven! Talk about easy when you use a cold fermentation to your advantage.

Can I do the whole bulk fermentation process in the refrigerator?

No. The wild yeast and bacteria are very, very slow when put in a refrigerator and brought to that cold temperature. Bulk fermentation at 78-80 degrees F is necessary for the dough development before being refrigerated. It would take many days for anything to happen to dough stuck straight in the refrigerator and the dough quality would suffer and break down.

Find My Favorite Sourdough Recipes Here:

Sourdough Artisan Bread Guide

Want more in-depth Sourdough instruction?

Check out my online sourdough classes or take a class in person.

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  1. I struggle to know when my dough is finished with bulk fermentation and ready to preshape. After 4 hours in a controlled 78 degrees My dough is nice and bubbly but very loose and flattens out in the counter. Is this over proofed?

    1. That doesn’t necessarily mean it’s overproved. When you go to shape it, does it hold its shape? It should hold its shape for a little while when you pre-shape it and then it will flatten out until you shape it and put it in a banneton. I usually look for about 30-40% rise, doming top and a few bubbles on the surface.

      If it doesn’t hold its shape, give it a few more strengthening folds or add in some slap and folds at the beginning.