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Testing Sourdough Proofing Times

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Sourdough Proofing Times

Testing sourdough proofing times

Have you ever stood there poking your dough wondering what you were supposed to understand from digging your finger into your dough? Well, you aren’t alone.

I’ve just begun exploring the fermentation process in more depth, to better understand what’s going on, improve my baking, and be able to help you out with any questions you may have.

In this test, I discovered what my best proofing times are at 25c / 77f and also that a little sneaky tweak in bulk fermentation would have a dramatic impact on the crumb.

You can watch the video of the experiment at the bottom of this article.

Why do we proof the dough in the basket or banneton?

After the bulk fermentation period, the dough is divided into individual portions and shaped, preparing the dough for the final part of its fermentation journey.

Proofing the dough in a sourdough basket or banneton, supports the dough during the final part of the fermentation, allowing the dough to take the shape of the basket, before baking at the optimum point (hopefully!)

Sourdough doesn’t need to be proofed in a basket, for example, sourdough ciabatta and baguettes are proofed on a couche (baker’s cloth), or the dough could be proofed in a tin for a sandwich loaf.

Knowing when the final proof is completed and the dough is ready to bake is one of the trickiest things to get the hang of. The dough should be left to expand enough to give us a nicely textured crumb and a loaf that “springs” in the oven. Leave it too long and you run the risk of over proofing resulting in the dough deflating.

I wanted to have a look and see how different stages of proofing affect the loaf, especially the crumb. The flavour of the bread will also be affected depending on the overall time the dough ferments. Although I didn't notice any difference with such small differences in time.

The four test subjects

For this experiment I’m comparing 4 different doughs:

Dough 1: Bulk ferment to 100% increase in volume - no proof ambient proof in the basket, retarded in the fridge immediately, for 18 hours

Dough 2: Bulk ferment to 100% increase in volume - 1-hour ambient proof followed by an overnight retard in the fridge for 18 hours.

Dough 3: Bulk ferment to 100% increase in volume - 2-hour ambient proof followed by an overnight retard in the fridge for 18 hours.

Dough 4: Bulk ferment to 75% increase in volume - 2-hour ambient proof followed by an overnight retard in the fridge for 18 hours.

The bulk fermentation and the proofing in the basket were carried out in a temperature-controlled chamber at 25 degrees Celcius or 77 degrees Fahrenheit. The cold retard in the fridge was carried out at 3 degrees Celcius or 41 degrees Fahrenheit.

Cold retarding in the fridge

I’ll be retarding all of the doughs in my fridge overnight before baking the next day. This is how I bake regularly so it makes sense to continue that for this experiment.

I knew that the dough must continue to proof in the fridge as the temperature of the dough would take some time to drop and stall the fermentation. I decided to pop a continuous read thermometer into one of the pieces of dough to see how long it took.

The dough went into the fridge at 25c / 77f and took virtually eight hours to drop to 5c / 41f. So, now I know that the dough will continue to actively ferment for several hours in the fridge, which means it could still overproof during the cold retard. This period in the fridge should be accounted for when judging when to begin the cold retard.

The recipe & process

I completed the experiment over a couple of days so I made 2 double batches of dough. Each batch weighed 1600 grams, which gave me enough dough for two 750g pieces for the loaves and 100 grams for the control piece.

The control piece of dough would be removed from the main dough after the initial kneading and placed into a jar. I marked lines on the outside of the jar so I could monitor the increase in volume during the bulk fermentation. The jar was kept in the fermentation chamber at 25c / 77f.

I used my sourdough calculator to work out how much dough I would need to make a double batch and have enough for the control. I used 548 grams of water, 208 grams of active sourdough starter at 100% hydration, 826 grams of strong white bread flour and 19 grams of salt.

I mixed the ingredients into a rough dough, let it rest covered for 15 minutes in the chamber and then kneaded for 2-3 minutes until the dough was smooth. This is when I removed the dough for the control and placed it in the jar.

The dough was stretched and folded twice, the first time was 30-minutes after kneading, and the second 60-minutes after kneading.

After ninety minutes from the kneading session, I divide the dough into two pieces, shaped it into dough balls and placed them into two individual bowls. Whenever I wasn’t working with the dough it was kept in the chamber at 25c / 77f.

After bulk fermenting, the dough was shaped and placed into a sourdough basket and proofed in the chamber and then retarded in the fridge until baking the next day.

The loaves were scored and then baked on a baking stone that had been preheated in the oven to 220c / 430f. The loaves were covered for the first 20 minutes of the baking with a large pan and then baked for a further 25 minutes uncovered.

The loaves were cooled on a wire rack to room temperature before slicing.

The results

Test subject 1

Bulk fermented @ 25c / 77f - increased to 100% of it’s original volume
Retarded immediately in the fridge at 3c / 37f for 18 hours

The dough felt tight before it was retarded in the fridge. When I “poked” it the dough responded with lots of energy pushing back quickly. This could have proofed for longer, without a doubt.

The shape of the loaf was full with a nice open ear, the dough sprang well in the oven. A month or two back this would have been the loaf I was shooting for, but now, I knew the crumb might disappoint a little.

Sure enough, the crumb was uneven with irregular holes that ranged in size, from small at the bottom of the loaf, to huge at the top.

The crumb wasn’t gummy and still had a nice soft texture. But the crumb was a little too irregular for what I’m trying to achieve.

Test subject 2

Bulk fermented @ 25c / 77f - increased to 100% of it’s original volume
Proofed in the basket for 1 hour @ 25c / 77f
Retarded in the fridge at 3c / 37f for 18 hours

When I touched the dough before retarding it felt nicely inflated but I knew it could cope with the continued proof after placing it in the fridge. Tricky to explain, but it felt right.

This produced a nice round, plump loaf. There wasn’t much of an ear but I think that was down to my scoring technique. On the whole, the outside was very nice.

The crumb was a lot more even with some nice holes, but not too big. There was only one slightly large opening in the crumb.

Overall I was pleased with this bake, and if I’d scored the dough a touch deeper before baking I think this would be a total success.

Test subject 3

Bulk fermented @ 25c / 77f - increased to 100% of it’s original volume
Proofed in the basket for 2 hours @ 25c / 77f
Retarded in the fridge at 3c / 37f for 18 hours

Before retarding it in the fridge I very gently inspected it by touching it very carefully. It was close to being over-proofed. It felt very gassy, fully inflated and as if it was ready to start deflating. I wasn’t confident this would survive the period in the fridge, but survive it did.

Surprisingly, the dough sprang in the oven producing a nicely shaped loaf, I wasn’t expecting that. But the crumb looked as though it had started to collapse a little. There were irregular holes and a lot of the crumb was quite tight.

Test subject 4

Bulk fermented @ 25c / 77f - increased to 75% of it’s original volume
Proofed in the basket for 2 hours @ 25c / 77f
Retarded in the fridge at 3c / 37f for 18 hours

I knew there was no point in pushing the proof in the basket any further, so I decided to reduce the bulk fermentation, stopping it when the dough increased to 75% of its original volume. After shaping the dough it was proofed in the basket for 2 hours in the chamber.

This dough felt super before it was retarded in the fridge. Stopping the bulk fermentation a little earlier and shaping seemed to tighten up the structure of the dough. It felt really good, well inflated, but strong.

After baking, the loaf was a little flat for my liking, “pancake” springs to mind. I’m not sure why this didn't spring so nicely in the oven. More investigating is needed!

The crumb was absolutely perfect for me. There was a nice open structure without the holes being too large, they were also evenly spread throughout the crumb.


Reducing the bulk fermentation slightly to a 75% increase in volume and proofing for 2 hours at 25c / 77f before retarding produced the best crumb for my liking. Although I need to work on the shape of the loaf a little.

What I enjoy in a sourdough loaf probably isn’t what you would enjoy, so I’d encourage you to experiment with the process and see how those tweaks work for you.

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