I have a question about bulk fermentation timing. The question is basically: How do you optimize bulk fermentation? How long is too long for bulk fermentation or how short is too short?
For the kneading process there is the window pane test. For proofing, the finger indentation test. And I’ve studied recipes that provide time ranges for bulk fermentation. But who came up with those times and what criteria are they based on?
So how do you know you’ve optimally fermented your dough. If the dough collapses you’ve fermented too long, and perhaps you ferment an hour less next time? And iteratively hone in on an optimal time? Or is there a qualitative way of knowing - a rise in acidity levels for example?
Or am I overthinking this? Or is it solely a matter of experience and intuition?
Thanks all for your wisdom!
Yes, you are overthinking it because there is no "right" answer. And the best approach can be different depending on what results (and kind of bread) you want to achieve. The amount of bulk fermentation to use is really a range, not a number. And to some extent it can be traded off between bulk and final fermentation as well.
Note that the finger test for the final proof isn't always the best indication, either!
The conventional number for bulk fermentation is that the dough should have doubled in volume. This can be hard to judge depending on the container you use. Various threads on TFL have talked about a 40% rise (to try to get a more vigorous oven spring) to 300% (I sometimes let mine go that far).
You would have to let a bulk ferment run a very long time to get collapse with a mixture of common wheat flours, so that is unlikely to become a problem (there are exceptions, of course, but it's not common). Some flours are very touchy about the hydration, and one of these flours that would hold up well in a low-hydration dough might collapse with higher hydration. But that's not the usual case.
What would be more likely would be a bulk that was so long that most of the available sugars and starches got used up, leaving little food for the yeast during final proof. But even then you would need to push the bulk time pretty far to get to that state.
I usually go by volume of the risen dough, and also by the appearance of bubbles along the sides of the container (mine is translucent and I can see them.
Go for a rise of 100% (doubling) and don't worry about hitting it exactly. You can go on from there once you learn what you like.
TomP
There is a qualitative way to do this - and you've been doing it. There is a quantitative way - and it takes a l o n g time to understand - and it's not suggested. First - make bread the way you want and like - the rest comes later. Enjoy!
PS - over thinking - yes. Remember the principal.
It's normal to be unsure at the beginning and maybe overthink it. There is no single bullet proof method for the optimal fermentation. It depends on the recipe and the desired end result. The more experience you gain, the easier it will be to nail the fermentation.
Fortunately there are a few good guides and learning resources for beginners. They help you to One of them is The Sourdough Journey (https://thesourdoughjourney.com, has also a youtube channel and an Insta account, lots of information, sometimes pretty long videos).
Then maybe later invest $35 in Trevor J. Wilson's books Mastering Bulk Fermentation and Open Crumb Mastery. The books are not necessarily something for beginners. Trevor himself writes on the cover "For the Intermediate Sourdough Baker".
A good-sized, semi-transparent container with fairly straight sides is a 4L/1gal ice cream tub. Ice cream sold in this quantity is often sub-par, but makes decent milkshakes.
Overthinking it? - probably! But experience is rewarding and will guide you as to when bulk is done in future.
Breaking down the question, I ask, what is bulk fermentation for...
Beginning with the idea of this step, it was probably only coined as a thing since the on-set of commercial yeast (CY) baking. SD is a little different...
With regard to CY baking, I would say...
Bulk fermentation is done to develop strength, such that when you shape, the shape is more or less retained by bake time.
SD has the added complexity of gluten breakdown that advances slackening or sometimes tearing (overly acidic).
It is widely regarded that bulk may be sufficient when the dough is gassy, and so when shaped the pressure of gases and developing gases allow the dough to hold a shape.
Consider that an unleavened dough will never hold its shape if made taller than its equilibrium and will return to its natural state.
Stretch and fold only works if the dough is gassing... Otherwise equilibrium and then puddle from proteolytic enzymes.