10 Sourdough Bulk Fermentation Tips for Beginners

Bulk fermentation is one of the trickiest parts of sourdough baking, especially if you’re just starting out. It’s also the stage where many things can go wrong, leading to under-fermented or over-fermented dough. After years of baking and troubleshooting, I’ve found that small adjustments during bulk fermentation can make all the difference. Here are my top 10 tips to help you determine when your dough is ready.

What Is Bulk Fermentation?
Bulk fermentation is the first long rise in sourdough baking. It’s the stage where your dough develops flavor, structure, and strength. However, it’s not a one-size-fits-all process. Bulk fermentation time varies depending on several factors like temperature, the amount of starter, and dough hydration. Let’s dive into these factors first and then move on to practical cues you can use to know when it’s done.
When Is Your Dough Done Fermenting?
1. Temperature: The Most Critical Factor
Temperature plays the biggest role in determining bulk fermentation time. A warmer kitchen means faster fermentation, while a colder environment slows it down. For example, in summer, my dough ferments in just 3-4 hours, but in winter, it can take up to 12 hours. If your recipe suggests 6-8 hours, treat that as a guideline and adjust based on your kitchen’s temperature.
2. The Amount of Starter Used
The percentage of starter in your recipe directly impacts fermentation speed. A typical recipe uses about 20% starter in relation to the flour. Using more starter will speed things up, which is great in colder months. Conversely, using less starter slows fermentation, which is helpful during warmer seasons when the dough ferments quickly.
3. Hydration Level of the Dough
Hydration refers to the ratio of water to flour in your dough. High hydration doughs (like artisan sourdough) ferment faster because they’re wetter and more active. Low hydration doughs (like brioche or bagels) ferment more slowly. If your dough is very sticky and soft, it likely has high hydration and will ferment faster.
4. Bubbles on the Surface
Look for bubbles on the surface and sides of the dough. If you’re using a glass bowl, you’ll also see bubbles forming underneath. While bubbles are a good sign of fermentation, don’t rely solely on this cue. Even under-fermented dough can show bubbles early on.
5. The Jiggle Test
Gently shake the bowl or the dough itself to see if it jiggles. A nicely fermented dough will have a light, puffy jiggle. However, hydration affects this—stiffer doughs won’t jiggle as much as wetter ones. Still, it’s a fun and useful test to try!
6. Smooth and Tacky Surface
At the start of fermentation, dough is shaggy and sticky. As fermentation progresses, it becomes smoother and only slightly tacky. Wet or flour your finger and press the dough—it should feel soft but not overly sticky.
7. Finger Dent Test
Poke your dough gently with your finger. If it’s properly fermented, the dough will spring back slowly but not completely, leaving a slight dent. If it springs back too quickly, it’s under-fermented. If it doesn’t spring back at all, it’s likely over-fermented.
8. Domed Shape
Look for a slight dome on the surface of the dough. A well-fermented dough rises evenly and has a rounded, domed shape. Note that high-hydration doughs won’t dome as prominently, but you should still see some rise.
9. Pull Away Test
Check if the dough pulls away from the sides of the bowl. Fully fermented dough should come away cleanly with minimal sticking. Wet or flour your fingers for an easier time testing this.
10. Easy Release from the Bowl
When your dough is ready, it should come out of the bowl easily without tearing. If the dough sticks excessively or tears as you move it, it’s either under- or over-fermented.
Why People Usually Under Ferment Their Bread…
From my experience, most beginner sourdough bakers tend to under-ferment their dough out of fear of over-fermentation. If you’re unsure, I recommend leaving the dough to ferment a bit longer rather than cutting it short. Over-fermented dough is still usable—you can turn it into focaccia or another delicious treat. Under-fermented dough, on the other hand, lacks flavor and structure.
One of the most popular recipes on my blog is my speedy sourdough recipe, which uses a larger amount of starter and ferments quickly. Many beginner bakers succeed with it because the shorter fermentation time is easier to manage. If longer fermentations make you nervous, try a recipe like that to build your confidence.
Remember, bulk fermentation times will change throughout the year with seasonal temperature fluctuations and starter activity. That’s completely normal, and part of the joy of sourdough baking is learning to adapt. Use these tips as your guide, and don’t hesitate to experiment and make mistakes—that’s how you learn!
If you have any questions or other sourdough dilemmas, feel free to reach out. I’d love to help you troubleshoot or even create a video about your specific challenges! Let’s chat in the comments below.