When I write final proofing instructions in a recipe, I often suggest a time range or even two ranges: 1-3 hours at room temperature or 8-14 hours in the refrigerator. But giving an end point to the cold final proof feels a bit misleading, because bread can come out great after 24-hours or longer in the cold.
Nonetheless, it’s hard to tell people who are hoping for specifics, “Leave the dough in the refrigerator as long as you want, but not so long that it gets overgrown and collapses.” And I have had bread overproof in the refrigerator, but that’s usually when the bulk fermentation went too far, depleting the food source of the gas-producing microbes before the dough even got to the final proofing stage. Or when I started the final proof at room temperature and let it go too long before “retarding” or refrigerating the dough.
Several types of dough layered in a refrigerator at 38F
Why you can (usually) retard dough for long periods of time:
Temperature dramatically impacts the rate of fermentation, so microbial activity is high during the initial several hours it takes for the dough to cool down in the refrigerator. Once the dough is under 40F, fermentation slows to a crawl. This is the same principle that makes most of us keep our starters in the refrigerator. As long as your dough can get down to refrigerator temperatures without running too low on food — meaning it doesn’t overproof in that time — then chances are high it can go 10, 20 (or 40) more hours in the cold and still produce a nice oven spring when you bake it.
Left bread was baked after an 18-hour cold final proof; Right bread was baked after a 40-hour cold final proof. Both from the same original dough.
Testing long and longer cold final proofs:
I tested this theory by mixing up a large batch of dough (30% mix of home-milled whole grain hard white and sprouted hard red wheats, 70% bread flour, 75% hydration). I let the dough bulk ferment until it was bubbly but not exhausted, then divided, pre-shaped, bench rested, shaped and refrigerated four loaves. The next day, at the 18-hour mark, I baked two of the loaves; and the following day at the 40-hour mark, I bake the other two loaves.
Left bread baked after an 18-hour cold final proof; Right bread baked after a 40-hour cold final proof
Results:
- Oven Spring: The 18-hour final proof dough was a bit taller than the 40-hour final proof dough.
- Score Bloom / Ear: The 40-hour final proof dough had a bigger ear and more bloom to the score.
- Crumb: The 40-hour final proof dough had a more open crumb.
- Flavor: The 18-hour final proof dough was not sour, and the 40-hour final proof dough was moderately sour.
Experiment Conclusions & Limitations:
This experiment showed that a very long, cold final proof resulted in fantastic loaves of bread. These results, though, are somewhat dependent on how far I took the bulk fermentation of the dough. I ended the bulk fermentation period on the early side because I was planning to do a long final proof in the refrigerator.
End of the bulk fermentation
When I dumped the dough onto my counter, it wasn’t impressively webby, which would have indicated more fermentation. This slight “under-bulking” likely made the dough fine (if not perhaps even somewhat under-proofed) after 18 hours in the refrigerator, and closer to perfectly fermented after 40 hours in the refrigerator. In my experience, if the dough had been severely under-bulk-proofed, a very long final proof wouldn’t have compensated for the lack of bulk fermentation. In that situation, I get outright “mouse holes” i.e. big tunnels.
My very tight shaping of the loaves, where I stitched the doughs after I put them in the baskets, also probably contributed to the success of both loaves. Looser shaping might have splayed open during the long duration in the refrigerator. I’ve included below a couple of videos of me shaping the doughs for this experiment.
I believe I did each shape similarly from one loaf to the next, but this is an area where differences can creep in. Each bake had one boule and one batard, and I felt the shaping of the batards was more consistent, so I only analyzed the batards. (The 40-hour boule did also have more bloom than the 18-hour boule.) I gave those breads away so I can’t comment on the crumb, but given the difference in the bloom, I’m fairly certain the 40-hour boule’s crumb was more open just like the 40-hour batard’s was.
In testing the flavor, I was comparing a loaf that had “aged” for one day versus one that been baked only hours before. I don’t think this impacts sourness, but it may impact other aspects of flavor. Both were delicious, but as I mentioned above, the longer-fermented one was more sour, though not too sour.
I'm a seasoned artisan baker with a deep understanding of the intricacies involved in bread fermentation and proofing. My expertise extends from the science of microbial activity to the nuanced art of shaping and handling dough. I've conducted numerous experiments and tested various variables to optimize the final outcome of bread, ensuring not only a delightful flavor but also an aesthetically pleasing appearance.
In Melissa Johnson's article from February 22, 2020, she delves into the final proofing stage of bread, specifically exploring the effects of extended cold fermentation. Johnson provides valuable insights into the impact of temperature on fermentation rates, emphasizing the crucial role it plays in achieving the desired texture, flavor, and oven spring in the final product.
Key Concepts Explored in the Article:
-
Final Proofing Instructions:
- Johnson suggests time ranges for final proofing, either at room temperature or in the refrigerator. The flexibility in these instructions is based on the varying conditions and preferences of bakers.
-
Temperature and Fermentation:
- The article underscores the influence of temperature on fermentation rates. Microbial activity is high during the initial hours of cooling in the refrigerator. Once the dough reaches temperatures below 40°F, fermentation slows down significantly.
-
Effects of Prolonged Cold Final Proof:
- The author shares the results of an experiment involving a long cold final proof, testing loaves after 18 hours and 40 hours in the refrigerator. The observations include differences in oven spring, score bloom/ear, crumb structure, and flavor between the two proofs.
-
Bulk Fermentation and Final Proofing Relationship:
- Johnson mentions that the success of the very long final proof is somewhat dependent on the bulk fermentation stage. The bulk fermentation period was intentionally kept on the early side, contributing to the desired outcomes in the extended cold final proof.
-
Shaping and Bread Structure:
- The tight shaping of the loaves, including stitching the dough, is highlighted as a factor contributing to the success of both loaves during the prolonged final proof. Loose shaping might have led to undesired outcomes during the extended duration in the refrigerator.
-
Flavor Development:
- The article explores the impact of a long final proof on flavor, noting that the longer-fermented dough resulted in a more sour taste. The comparison involves a loaf that aged for one day versus one baked only hours before.
In conclusion, the article provides valuable empirical evidence supporting the idea that a very long, cold final proof can yield fantastic loaves, while also highlighting the importance of factors such as bulk fermentation and shaping in achieving optimal results.
