We Reviewed the Challenger Fermentation Mat and Recommend It for Sourdough Bakers

We Reviewed the Challenger Fermentation Mat and Recommend It for Sourdough Bakers

the challenger fermentation mat
Serious Eats / Jesse Raub

One of the more challenging parts about sourdough baking in the colder months is maintaining proper starter and dough temperature. Natural yeast cultures in a starter are slower to reproduce than instant or active dry yeast you can buy from the store, and consistent temperatures between 74ºF to 80ºF are necessary to allow bread to rise. 

Commercial bakeries have proofing racks that allow fully enclosed temperature control, but options for home bakers are limited. There are countertop proofing boxes available, but they can be expensive and their size and shape is restrictive. The Challenger Fermentation Mat is designed to be more versatile: instead of a box, it’s a long, rectangular silicone mat with heating elements that radiate upwards, allowing more freedom for which type of proofing container you want to set on top of it. It also has a temperature control box that allows you to set a custom temperature, and when you’re done, you can roll it up for easy storage.

We evaluated the mat’s performance and usability, to see whether we recommend it (or not).

The Tests

a heating mat with a sourdough starter on top and a thermocouple taking the temperature
Serious Eats / Jesse Raub
  • Starter Test: We made a 5-hour levain in a glass jar with 57ºF water and 68ºF flour and set it on the Challenger Fermentation Mat set to 90ºF. We placed one temperature probe in the starter and one in the air to measure ambient temperature and recorded the results. 
  • Dough Test: We mixed the levain into a 2-loaf batch of dough made with 54ºF water and 68ºF flour and set it in a plastic proofing box on the Challenger Fermentation Mat set to 90ºF. We placed one temperature probe in the dough and one in the air to measure ambient temperature and recorded the results.
  • Large Batch Test: We repeated both the starter and dough tests, this time doubling the recipe for a 4-loaf batch to see if the mat could handle a larger thermal mass.
  • Usability and Cleanup Tests: We noted how simple the mat was to set up and program, as well as how easy it was to clean. 

What We Learned

It Maintained Temperatures Well

During our testing, we found that the mat was able to maintain consistent temperatures over long periods of time, which helped both our starter and our bread dough ferment properly. It held our starter between 74ºF and 80ºF for more than four hours while the room temperature floated between 64ºF to 68ºF every 30 minutes due to home heating cycles. The mat also helped keep our dough temperature stable for three hours. 

It did take a little finesse to reach our target of 78ºF, but as the dough mat says on its surface: “mat temperature is not dough temperature.” In order to get our levain and dough up to the 74ºF to 80ºF range, we had to set the mat a little higher and monitor its temperature the first time we used it. 

It Took Time To Heat Up

a batch of sourdough showing 66 degrees Fahrenheit while the heating mat is set to 90 degrees Fahrenheit
Serious Eats / Jesse Raub

The mat’s temperature consistency was stellar, but it wasn’t efficient at heating. Both our levain and bread dough began around 66ºF, and it took around two hours for the levain to hit peak temps of 80ºF while our dough took around three hours to clear 74ºF, even with the dial cranked to 100ºF. As a result, we had to extend the proofing time by 30 minutes, though this would likely be less of an issue in spring or fall when the starting water temperature is higher and the room temperature is warmer. 

The Mat’s Shape Was Super Versatile 

sourdough starter in a jar being warmed by a heating mat
The fermentation mat can even warm a sourdough starter jar that might be too tall for a proofing box.Serious Eats / Jesse Raub

The main advantage of this fermentation mat over other countertop proofing boxes is just how versatile it is. It’s long enough to place two medium-sized mixing bowls on it side-by-side, or even a proofing box with your starter jar next to it. Even more useful than that is its portability: because the mat can just roll up when not in use, it takes up very little storage space, and can even fit in a drawer.

It Struggled With Larger Volumes

To test the fermentation mat’s limits, we doubled our regular recipe for a 4-loaf batch of dough. Both our bigger levain and dough struggled to hit our target 74ºF to 80ºF target, forcing us to extend our proofing time for both by nearly two hours, though most people wouldn’t face this issue with standard bread recipes.

It Worked Best with Flat-Bottomed Boxes

a plastic box has a temperature probe showing the sourdough dough inside is 80.9 degrees Fahrenheit
Serious Eats / Jesse Raub

Along with the Fermentation Mat, we also tested out Challenger’s Proofing Box as part of their Proofing Kit. While the mat worked well for jars, bowls, and other boxes, the Challenger Proofing Box has a completely flat bottom which gave it a lot of direct contact with the Fermentation Mat. The other plastic proofing box we tested had plastic rails on the bottom that elevated it off the counter slightly, and the heat transfer wasn’t as direct.

The Verdict

The Pros: For most home bakers, the Challenger Fermentation Mat is a great option for maintaining proper fermentation temperatures for your starter, levain, or dough. Because it’s a mat (as opposed to a box), it allows you to use whatever fermentation vessel you already own (though completely flat-bottomed boxes work best), and its ability to roll up when not in use makes it easy to store. We also found it was easy to program the desired temperature, quick to set up, and easy to wipe clean with a damp cloth if any dough were to spill over. 

The Cons: The biggest drawback is that the mat can take a while to heat up, extending your proofing times, and just isn’t powerful enough for larger batches of dough. However, for most home bakers this wouldn’t be a problem. 

Key Specs

  • Dimensions: 10 x 21 inches
  • Wattage: 20 watts
  • Temperature range: 40ºF to 108ºF
  • Care instructions: Wipe clean with a damp cloth as needed
  • Price at time of publish: $76


Is a fermentation mat or proofing box worth it?

For people who live in colder areas, it’s harder to maintain the proper temperature for sourdough fermentation. A fermentation mat or a proofing box can help keep your sourdough starter and bread dough at the right temperature for the entire proofing process. 

What temperature should a proofing box be?

Sourdough requires gentler heat and longer proofing times than instant or active dry yeast, and the ideal temperature range is between 74ºF to 82ºF. If the temperature is too cool, the dough won’t rise in time, and if the temperature gets too warm, the fermentation will start to break down gluten strands, and the dough will collapse.