How to keep your sourdough starter & dough warm all year long

One of the biggest struggles I see when people are making sourdough is dealing with cold temperatures. It can be so frustrating to start a sourdough starter from scratch, only to feel like nothing is happening. Or when you mix up a beautiful batch of dough, but it just won’t rise—what went wrong?

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One of the first things I always ask is: Have you checked the temperature?

Temperature is one of the most important (and often overlooked) factors in sourdough baking. If your starter is too cold, fermentation slows down or stalls completely. If your dough isn’t warm enough, it won’t rise in a timely manner or at all. The good news? There are plenty of simple ways to keep your sourdough starter warm all year long—even in a chilly kitchen.

In this post, I’ll walk you through the best ways to keep your sourdough starter and dough warm, where to store it, and what tools can help so you can keep your bakes on schedule no matter the season. And if you don’t already own a meat or candy thermometer, now’s the time to grab one—it’ll be your new best friend in sourdough baking!

Ideal temperature for sourdough 

The ideal temperature for a sourdough starter, whether you’re creating or maintaining it, is 77-85°F. If your starter stays below 80°F, it will develop a stronger, vinegary flavor due to increased acetic acid production. On the other hand, warmer temperatures create a milder, flavor.

While your starter can handle some warmth, I don’t recommend letting it go over 85°F—and definitely not above 90°F. The hotter it gets, the more acidic it becomes, which can weaken the gluten structure and cause your dough to overproof too quickly.

The good news is you’d have to reach 120°F to actually kill the yeast and bacteria in your starter. So if it ever gets a little too warm, don’t panic—it’s most likely not dead!

Warmth is going to be really important when making a new starter but once your sourdough starter is well-established, it can still rise at cooler temperatures in the upper 60s°F to low 70s°F—it’ll just take longer. Lower temperatures slow down fermentation, so you may need to adjust your timing and use smaller feeding ratios to ensure your starter when you need it.

What about dough proofing temperatures?

The best temperature for proofing dough depends on the recipe. Long, slow ferments (like my overnight sourdough bread) typically proof best in the mid to upper 60s°F, while my same-day sourdough recipe calls for around 75°F. Some recipes even specify 80°F proofing temperatures, which is why it’s always important to check the directions.

How to keep your sourdough starter warm

Warm places in your house

If it’s the middle of winter or you have the AC blasting, finding a warm spot can help keep your starter and dough rising on schedule. Here are a few naturally warmer spots to try:

• On top of the refrigerator – The fridge’s compressor generates heat, which rises to the top, creating a consistently warm spot.
• Near a heating vent or radiator – If your heater is running, placing your starter near a vent or radiator to provide some warmth.
• Near a fireplace – A fireplace can add extra heat, but be careful not to place your starter too close, or it may get too warm.
• Upstairs – Since warm air rises, upstairs rooms are often a few degrees warmer than downstairs, making them a better spot.
• Boiler room or closet – If you have a boiler, the surrounding area tends to stay warm, making it a good option. 

Finding the right spot can make a big difference, so experiment with different locations in your home to see what works best!

DIY warming hacks 

If you aren’t ready to invest in paid tools to keep your sourdough starter and dough warm, here are some free and easy DIY methods you can try at home:

• Oven with the Light On- This method works well, but I’ll be honest—it makes me nervous because I’ve accidentally baked things I didn’t mean to before! If you try it, put a sticky note on the oven and make sure everyone in the house knows to check inside before turning it on. Also don’t put anything super close to the light bulb as it is possible to get too warm in there.
• Microwave as a Proofing Box- Heat a glass of water in the microwave until boiling, then place your starter or dough inside with the hot water (without turning the microwave on). Quickly close the door to trap the warmth and humidity.
• Wrap It Up- Don’t leave your starter sitting directly on a cold kitchen counter, especially if you have quartz or granite, as these surfaces stay chilly. Instead place it on a folded towel or wrap the jar in a towel or slip it into a wool sock for extra warmth.
• Warm Water Bath- Fill a bowl with warm water (around 85°F) and set your starter jar inside. Don’t fully submerge the jar—just let it rest in the water. Refresh the water as needed to maintain warmth.
• Use a Cooler for Insulation- Some bakers swear by using a small cooler as a makeshift proofing box. Try microwaving a rice sock or filling hot water bottles, then placing them in the cooler alongside your starter or dough to keep things warm.

Best tools for keeping a sourdough starter and dough warm

If you want reliable, consistent results every time then investing in a warming tool can make your life easier. Here are some of my favorite options and ones that I don’t think are worth the hype. 

Brod & Taylor Proofing Box

Temperature range: 70-195˚F

While this proofing box is an investment, I think it’s worth every penny. I went years without one, and while it’s not essential, my bakes became much more consistent and my timing more predictable. This is my number 1 pick if it is in the budget. 

Pros:

• Precise temperature control – Your dough and starter will actually reach the temperature you set it to (the biggest plus in my eyes). 
• Spacious – It can fit most 9×13-inch pans (unless they have handles) and even has a rack for a second row of items. 
• Collapsible – It’s bulky on the counter but folds flat for storage.

Cons: 

• Higher price point.
• Takes up a good amount of counter space when in use.

Bakehouse Essentials Dough Mat 

Temperature range from 60-120˚F.

Before getting my proofing box, I exclusively used this mat—and I still love it! It’s flat, easy to store, and great for placing under pans during the final rise of cinnamon rolls or bagels. This would be my second pick. 

Pros: 

• Easy to store.
• More affordable option.
• Doesn’t take up much counter space.

Cons: 

• Not fully enclosed – The set temperature of the mat isn’t necessarily the temp your dough and/or starter will reach (this is why the proofing box is my #1 pick). You may need to increase the temperature of the mat above your desired temperature. 
• Uneven heating – The bottom of the dough or starter will be warmer than the top.

Pro tip: Place a towel underneath the mat and over your dough to help maintain a consistent temperature. Some bakers have recommended creating a DIY proofing box by placing an overturned box on top of the mat. I haven’t tried it but if you do let me know in the comments how it goes.

You can get 10% off the mat with coupon code country10 at checkout.

Seedling Heat Mat 

A seedling heat mat is a budget-friendly way to keep your starter warm, but choose one with a temperature-controlled gauge. If you get a basic mat without a thermostat, don’t place your starter or dough directly on it—these can get too hot. Instead, wrap the mat loosely around the jar without direct contact.

Pros:

• Very affordable.
• Easy to store. 
• Doesn’t take up much counter space.

Cons: 

• Not fully enclosed – Like the dough mat, the set temperature doesn’t guarantee your dough will reach that temp.
• Uneven heating – The bottom of your starter or dough will be warmer than the top.
• Quality varies – When buying from Amazon, it’s hard to know if the mat will heat evenly or last long. This is why I prefer the Bakehouse Essentials Dough Mat for a more reliable option.

Sourdough Home or Sourhouse Goldie

I don’t personally use these, but many sourdough bakers like them. That said, I don’t think they’re worth the price—they only fit a single jar of sourdough starter, so you’d still need another solution for proofing dough. If you’re spending this much, I’d recommend getting a proofing box instead.

Pros: 

• Compact – Takes up very little space.
• Keeps your starter in the ideal range.
• Can cool down the starter if it’s fermenting too quickly.

Cons: 

• Only fits one jar of starter—not useful for proofing dough.
• Expensive for what it does.