Sourdough in Hot Weather: Summer Baking Tips

Every summer, my inbox fills up with the same desperate messages: "Joe, my dough turned into a puddle," or "My starter doubled in two hours and I missed it," or simply "Help, it is 90 degrees and everything is overproofing." Sound familiar?

Hot weather is the single biggest variable that throws off sourdough bakers. The recipes and timelines you have been following all spring suddenly do not work. Your bulk fermentation that used to take 6 hours finishes in 3. Your starter peaks and collapses before you even wake up. It can feel like everything you learned has stopped working.

But here is the thing, nothing is broken. Your starter is thriving. Fermentation is just moving faster. You need to adjust your approach to match the temperature, and once you do, summer baking can be some of the best baking you do all year.

Why Heat Changes Everything

Yeast and bacteria are living organisms, and they love warmth. Between 75°F and 82°F (24-28°C), fermentation happens at an ideal pace for most recipes. But above 85°F (29°C), things accelerate dramatically. The yeast produces gas faster, the bacteria produce acid faster, and the gluten starts to break down sooner.

7 Strategies for Hot Weather Baking

1. Use Cold Water (or Even Ice Water)

The easiest way to slow down fermentation is to start with a cooler dough. Instead of room temperature water, use water straight from the fridge, around 40 to 50°F (4-10°C). For really hot days, use a mix of water and ice cubes. Your target dough temperature after mixing should be around 75 to 78°F (24-26°C).

2. Reduce Your Starter Amount

If your recipe calls for 100g of starter, try using 50 to 75g instead. Less starter means fewer organisms competing for food, which slows the overall fermentation. You will still get a fully fermented dough, it just takes a bit longer, which is exactly what you want.

3. Move to the Fridge Earlier

In winter, you might bulk ferment entirely at room temperature. In summer, consider doing just 1 to 2 hours of room temperature bulk fermentation (with your stretch and folds), then moving the dough to the fridge for the rest. The cold slows everything down to a manageable pace.

4. Feed Your Starter Differently

Your feeding schedule needs adjustment in summer. If your starter normally peaks at 6 hours, it might peak at 3 in a hot kitchen. You have two options: feed it with a higher ratio (1:5:5 instead of 1:1:1 to slow peak time) or feed it and put it straight in the fridge until you are ready to bake.

5. Bake Early Morning or Late Evening

If your oven heats up the kitchen (of course it does), try to bake during the coolest parts of the day. I do most of my summer baking before 8 AM. The oven runs while the house is still cool from the night, and by the time the kitchen heats up, the bread is done and the oven is off.

6. Find the Coolest Spot in Your Home

Not every room in your house is the same temperature. A basement, an air-conditioned bedroom, or even a tile floor can be significantly cooler than your kitchen counter. Move your fermenting dough to the coolest spot you can find.

7. Watch the Dough, Not the Clock

This is the most important advice for any season, but it is critical in summer. Forget the recipe timelines. Look at your dough: has it increased in volume by 50 to 75 percent? Does it feel airy and jiggly? Can you see bubbles on the surface and around the edges? Those are the signs that bulk fermentation is done, whether it took 3 hours or 8.

Summer Is Actually Great for Sourdough

Once you adjust your approach, summer brings real advantages. Your starter is at its most vigorous and reliable. Fermentation is consistent. And the warmer proofing temperatures produce breads with more open crumb structure and better oven spring. Some of my best loaves come out of July and August, once I stopped fighting the heat and started working with it.

The key is flexibility. Let go of rigid timelines and learn to read your dough. That skill will make you a better baker in every season.