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Temperature is the dial you can actually turn
Recipes give times, but dough runs on temperature. The same sourdough can finish bulk fermentation in four hours on a warm day and take nine on a cold one. You can’t easily change the weather or your kitchen, but you can change the temperature of the water you mix with, and water is the easiest ingredient to warm or cool.
This calculator uses the desired dough temperature method, a technique bakeries have relied on for decades. You pick the temperature you want the dough to be after mixing, tell it how warm everything else is, and it returns the water temperature that gets you there. It helps any home baker whose recipe timings drift with the seasons.
Why dough temperature matters
Yeast and the bacteria in sourdough work faster as they warm up and slow sharply as they cool. Most sourdough recipes are written for a dough around 24 to 26 °C. Start several degrees cooler and every stage stretches; start warmer and the dough can overshoot before you are ready for it. Hitting a consistent temperature is what makes a recipe’s timings repeatable.
Entering your temperatures
- Enter the target in Desired dough temperature. Without a figure from the recipe, 24 to 25 °C suits most sourdough.
- Measure and enter Room temperature and Flour temperature.
- Tick The dough includes a starter, levain or poolish if it does, and enter Starter or levain temperature.
- Choose a Mixing method. Pick My own friction factor to type a Friction factor you have measured.
- Optionally fill in Tap water temperature and Total water in the recipe under Ice (optional) if you need very cold water.
The result is Water temperature, with Temperatures counted and Friction factor used shown beneath it.
Worked example: a cool spring kitchen
You want the dough at 24 °C. The room and the flour are both 20 °C, the levain is 23 °C, and you mix by hand. The calculator returns:
- Water temperature: 31 °C
- Temperatures counted: 4
- Friction factor used: 2 °C
With a levain there are four contributors, so the target is multiplied by four: 24 × 4 = 96. Subtract everything that is not the water, 20 + 20 + 23 + 2 = 65, and what remains is the water: 96 – 65 = 31 °C.
The same case in Fahrenheit, with fields showing 75.2, 68, 68 and 73.4, gives 87.8 °F and a friction factor of 3.6 °F. Friction is a temperature difference, so it converts without the usual 32° offset.
Untick the levain box for a yeasted dough with the same room and flour, and the calculator counts three temperatures instead of four, asking for 30 °C water.
Now take a hot summer day: target 25 °C, room, flour and levain all at 29 °C, hand mixing. The water needs to be 11 °C. Enter a tap temperature of 25 °C and 700 g of total water, and the calculator splits it into Ice: 93 g and Tap water: 607 g. Melting ice absorbs a lot of heat, which is why a modest amount chills the whole batch. If you mix the same summer dough in a stand mixer instead, the required water drops to 3 °C and the calculator suggests adding your tap temperature to work out the ice.
About the friction factor
Mixing warms dough. The presets (0 for no-knead, 2 °C by hand, 10 °C for a stand mixer, 14 °C for a spiral mixer) are starting points, not measurements. Your real figure depends on the mixer, the speed, how long you mix and the size of the batch.
To find your own, mix a dough, take its temperature straight away, then work backwards: multiply that dough temperature by the number of temperatures counted, subtract room, flour, starter and water temperatures, and what remains is your friction. Enter it under My own friction factor next time.
Tips
- Measure, don’t guess. Flour stored in a cold pantry can be several degrees below room temperature.
- Very hot water is a warning sign. Above about 40 °C it can stress yeast and your starter. Warm the room or the flour instead, or accept a slightly cooler dough and a longer rise.
- Use the result to plan. With a reliable dough temperature, the estimates in the sourdough schedule planner become much closer to real life.
Water temperature FAQ
What if the calculator asks for water below freezing?
Even ice water cannot cool the dough that far. Chill the flour in the fridge for an hour, or accept a slightly higher dough temperature.
Does the starter really count as a separate temperature?
Yes. A levain can be a fifth of the dough, and a cold one straight from the fridge pulls the mix down noticeably.
Why multiply by three or four?
Each ingredient and the mixing contribute roughly equally to the final temperature, so the target is multiplied by the number of contributors before subtracting the ones you know.
How accurate is it?
Usually within a degree or two, which is close enough to keep timings predictable. The friction factor is the least certain part, so measuring your own improves accuracy most.