Get a precise bulk fermentation window for your sourdough based on dough temperature, starter activity and hydration level.
Dough Temperature
The single most important factor in fermentation speed
76°F
60°F75°F90°F
Starter and Dough Details
Tell us about your starter and recipe
Additional Factors
Fine tune your fermentation estimate
Estimated Bulk Fermentation Time
0
hrs
–:–
Finish Time
76°F
Dough Temp
50%
Target Rise
Fermentation Schedule
Temperature Effect on Speed
Cold (60°F)Ideal (76°F)Hot (90°F)
Bakers Notes
Full Breakdown
What Is Bulk Fermentation?
Bulk fermentation is the first and most important rise in sourdough bread making. It begins the moment you finish mixing your dough and ends when you divide and pre-shape it. During this period the wild yeast and bacteria in your sourdough starter consume the sugars in the flour, producing carbon dioxide gas that makes the dough rise and organic acids that give sourdough its distinctive flavour and texture.
Getting bulk fermentation right is the difference between an open, well structured crumb and a dense, gummy loaf. Ferment for too short a time and the dough will lack flavour and structure. Ferment for too long and the gluten network breaks down, making the dough slack and difficult to shape with a flat, sticky result after baking.
Simple guide: At 76 degrees Fahrenheit with a 20 percent starter at medium activity, most sourdough doughs take between 4 and 6 hours for bulk fermentation. Every degree cooler adds roughly 10 to 15 minutes. Every degree warmer removes roughly 10 minutes.
How to Use This Calculator
1
Set Dough Temperature
Measure your actual dough temperature with a thermometer after mixing. This is not your room temperature. Drag the slider to your reading.
2
Enter Starter Details
Select your starter percentage, hydration level and how active your starter is right now. A starter at peak doubles the fermentation speed versus a low activity one.
3
Get Your Schedule
Enter your start time and hit calculate. You will get a full timeline with fold reminders, estimated finish time and visual cues to watch for.
Bulk Fermentation Time by Temperature
Temperature is the single biggest variable in fermentation timing. The table below shows estimated bulk fermentation times at common dough temperatures using a 20 percent starter at medium activity and 75 percent hydration.
Dough Temp (F)
Dough Temp (C)
Estimated Time
Activity Level
65°F
18°C
9 to 12 hours
Very slow
70°F
21°C
7 to 9 hours
Slow
76°F
24°C
4 to 6 hours
Ideal
80°F
27°C
3 to 4 hours
Fast
85°F
29°C
2 to 3 hours
Very fast
Frequently Asked Questions
The most reliable sign is a 50 to 75 percent increase in dough volume depending on your recipe. The dough should look domed on top, feel airy and light when you gently pull the container, and show bubbles around the edges and on the surface. It should jiggle like jello when you shake the container. Time is a guide but always use these visual and tactile cues as your final confirmation.
The yeast and bacteria in your dough respond to the temperature of the environment they are actually living in which is the dough itself. Your room temperature influences the dough temperature over time but they are often quite different especially right after mixing. Cold water, cold flour from a cool pantry, or warmth added by friction during kneading all affect dough temperature independently of the room. Measuring dough temperature directly gives you a much more accurate starting point for timing.
Most experienced sourdough bakers aim for a dough temperature between 74 and 78 degrees Fahrenheit (23 to 26 degrees Celsius) during bulk fermentation. This range produces active fermentation at a pace that is easy to manage while also developing good flavour. Temperatures in this range give you a predictable timeline and enough working time to complete your stretch and fold sets comfortably.
Most recipes call for 3 to 4 sets of stretch and folds during the first two hours of bulk fermentation, performed every 30 minutes. Each set strengthens the gluten network and redistributes the temperature within the dough. After the final set the dough rests undisturbed until bulk fermentation is complete. You can also use coil folds or lamination as alternatives, both of which are gentler and work well for high hydration doughs.
You can but the term for this is a cold bulk or cold retard and it works differently to a room temperature bulk. In the refrigerator at around 38 to 40 degrees Fahrenheit fermentation slows dramatically and can take 12 to 16 hours or longer to complete. Many bakers prefer to do most of the bulk at room temperature and then cold proof the shaped loaf overnight rather than cold proofing the bulk dough. The results are more predictable and the shaped loaf holds its form better after shaping.
Over-fermented dough is one of the most common sourdough problems. When bulk fermentation goes too long the acids produced by the bacteria begin to break down the gluten bonds that give the dough its structure. The dough becomes very slack and sticky, spreads flat when you try to shape it and often sticks aggressively to your work surface. After baking it produces a dense, gummy crumb with a very sour flavour and poor oven spring. Unfortunately there is no way to reverse over-fermentation once it has happened.
Yes, slightly. Higher hydration doughs provide a more fluid environment for yeast and bacteria to move through, which modestly speeds up fermentation activity. The difference between a 70 percent and an 85 percent hydration dough at the same temperature is typically 15 to 30 minutes over a full bulk fermentation. The bigger practical impact of high hydration is that it makes over-fermentation signs harder to spot visually and makes the dough more sensitive to small errors in timing.
