I’m trying to understand what’s actually happening when a dough becomes “over-proofed”.
My initial thought was that the yeast had ran out of glucose to ferment into CO2 and therefore, no more rise. However I feel like that’s unlikely as, for that to happen, the enzymes would have to have ran out of starch to break down and I feel like a dough without any starch would have a very different texture all together? I’ve seen dough's that have been over-fermented and the gluten structure is gone, they’re completely un-salvageable.
On top if this, I’ve also read that you can salvage an over-proofed dough by knocking it back, re-shaping and re-proofing. That wouldn’t be possible if the yeast had ran out of “food”.
So with that in mind, I feel like it’s more to do it’s the fact that the more the dough rises, the weaker the structure becomes to a point where the dough struggles to support it’s own weight and eventually collapses as gas bubbles start to burst. Hence why slashing an over-proofed dough tends to make it go flat.
I also originally thought that you could prevent an over-proof by shortening the bulk fermentation, based on the theory that the dough had a “time limit” from the moment the yeast was added to the moment it ran out of food. Now I believe shorting the bulk ferment can still help, but instead because there will be a lower population of yeast going into the final proof so proofing should therefore be slower, not because of this "time limit".
So assuming that’s right, and I’m over-proofing my dough, what's the best way to prevent it happening in the future? Should I cut down the bulk ferment or the proof? I know there's the poke test for proofing but how do you know when the bulk ferment is done? How regularly do people poke test? My recipes say to check it after 1 - 1.5 hours. I've always put it in the over after 1 hour because it only springs back about half way. I'm thinking maybe I should start checking after half an hour.
Of course I could be barking up the wrong tree all together. In which case, please feel free to correct me. I’m a biology student so the science behind bread making is one of the things that drew me to it.
For reference, the recipe I've been using:
- 500 g Flour
- 350 g Water (room temp)
- 10 g Salt
- 8 g Dried active yeast (I usually use 4 g, see below)
Recipe:
- Mix
- Rest 20 mins
- Knead 5 - 10 mins
- Bulk Ferment 1 hour (I usually use 4 g yeast and BF for 3 hours but I needed to make a quick loaf. The outcome is often very similar).
- Pre-shape
- Bench Rest 20 mins
- Shape
- Proof 1 hour
- Bake with steam
I made this recipe yesterday when all temps were around 23 - 24 C (73 - 75 F). It rose nicely during BF and Proof. But when it went into the oven, nothing, zero rise, in fact it dropped a bit. This is a hurdle I'm struggling to get over. I usually get some rise at least buts it never great, I've never had it "burst out the seam".
Good question.
I think many bakers use the term to convey a number of things but strictly speaking to "over-proof" means only that the dough has risen beyond the limits of its structural integrity. Running out of fermentable simple sugars is termed "exhausted". And gluten structure that has been compromised by enzymatic action or the effect of increased coagulation or solubility would be "degraded".
That's right, bread is comprised mostly of starch and only a small part of the flour actually gets fermented. The physical force of milling flour causes some of the native starch to break into fractions which then can be cleaved by amylase enzymes to release fermentable simple sugars.
Broken starch is therefore required to allow for fermentation to occur but too much can cause problems. The milling of hard wheats generally creates greater starch damage (~8%) while softer grains break more easily and give less broken starch (2-4%). This is why some bread flours made from hard wheat varieties often have malt added.
Yeasted doughs suffer from less degradation and chemical changes that might compromise gluten integrity so typically knocking them back or re-mixing them is not a problem. Depending how much yeast fermentation has occurred you may need to consider dosing with sugar or amylase (from diastatic malt) to prevent exhausting the dough. Degradation depends on the flour type(s) used and how much tolerance they have.
Hi mwilson,
Thanks for the response. So a dough that has become "over-proofed" is generally more down to the limit of its structural integrity than the fact that the yeast has exhausted its food supply? Cool, sounds like I was on the right track :)
So based on the bottom part with my recipe and method. Why do you think my dough isn't rising in the oven? I originally found it hard to believe that my dough could be over-proofed as the fermentation and proofing times are pretty short anyway but maybe, on a warm day, that is still too long? Would I be best to reduce the bulk fermentation? or the proof? or both?
My immediate thought is to reduce the proof, as that's the part that builds the final structure. And if it can be salvaged by knocking it back and starting again, then its surely less of an issue with the yeast.
On top of this, I've seen people everywhere saying that a longer bulk fermentation improves the flavor so I find it hard to believe that I'm already on the limit of that (for longer fermentation I would obviously reduce the amount of yeast added at the start anyway). Unless reducing the bulk means a lower population of yeast going into the proof and therefore a slower proof.
My guess is that the bulk fermentation is more forgiving than the final proof. But what are you thoughts?
Yeast dose is fine. But your total processing time is incredibly short. To make bread that quick would require an intensive mix. And 70% hydration is probably too high...
Where are you located and what flour are you using?
UK, and just a strong bread flour, the brand sometimes varies, its whatever my local bakery has at the time haha. I need to find one and stick with it really.
I tried an experiment today to see if I was over proofing. I tried the 4g version with the 3 hour bulk ferment. I decided to pay much more attention to the dough and check it every half hour or so. After 2 hours I decided the dough had doubled in size, looked nice a puffy and I decided to move it on. Then during the proof I done the poke test at 30 mins, decided it was ready and threw it straight into the oven.
I had the best oven spring I've ever had. I even got my first tiny little ear on one of the cuts. I'm baffled haha.
The room and dough temp remained close to 25 C (77 F) throughout the whole process so I guess It was just moving fast? I've been over-proofing it this whole time?
Ditto mwilson that you have an unusually short total processing time, but if it's working for you, that's great.
If you want the flavor benefits of long fermentation, the easy way is to make part of the dough as a poolish a day or two in advance. Poolishes can sit and bubble until you get around to using them. OTOH, as you say, with a bulk ferment you're more constrained because if you wait too long the dough goes slack.
I think, what I've learned from this, is that yeast is way more temperature sensitive than I realized. I mean I understand yeast is a living organism and there's a temperature range in which is thrives, like most things, but I was thinking more in differences of 5-10 minutes, not literal hours.
The book I got these recipes from could have been written with a more average room temp of around 21c, where as at the moment, I'm working in more like 24/25c. I'm also reading "Tartine Bread" where he uses proofing temps closer to 26/27c, so I can already tell those times are going to be longer for me.
The crumb wasn't quite as open as I've had in the past so maybe I could have let it rise a little longer. Either that or maybe I need to be more delicate with my shaping?
I have tried a poolish and it came out pretty well. I keep meaning to do it again. I'm trying to learn to make a range for different occasions. This is the "I've woken up this morning and I wan't some bread this afternoon" range. Then I want to look at making standard loaves with more flavor. Then I want to get to the more lengthy process of sourdough.