A short mix and the wonder of poolish
French dough made with poolish is a wonderfully extensible and easy to shape. Unfortunately for me this particular batch was a bit on the short side.
As a home baker I always have trouble getting a nice open crumb, usually whatever I was making whether enriched or lean would always be tight. Which is not to say that it was "bad" but it was a really troubling condition of my bakes. Baking in a bakery on the other hand is quite the opposite. Achieving a tight crumb in a spiral mixer requires intentionality, an oddity when we consider the fact that its one thing to mix doughs by hand and quite another to mix them in a machine. Mixers are rough, unyielding, and can go on as long as they have the power to; hand mixing with kneading or folding, depending on your bready sensibilities, is comparatively gentle and definitely not a process that you can do forever. So you would think that mixing a dough by hand would always give you a good open crumb. But my own experiences seem to invalidate that hypothesis. So stepping back, we say that your cell size is dependent on the level of gluten development (also dependent on how strong your flour is) because mixing, in addition to incorporating all your ingredients, primarily develops gluten, by hydrating flour.
So if there are additional factors besides pure gluten development and flour strength, what are they? The first and most obvious is the proof. It has to be, its the period of time when you allow your yeast to fill up cells with gas, and the more gas, the more these cells are stretched and thus bigger air cells. Which brings up another point, dough extensibility allows maximum volume. I would imagine bulk fermentation also plays a minor role in this, as without good fermentation (and momentum), a good proof will be longer and more difficult. A good hot oven as well promotes maximum oven spring as the yeast are introduced to so much heat.
The one thing I don't understand is the effect of shaping on air cells. I'm reasonably confident good shaping will facilitate an open crumb, but then again to a certain extent a "good" crumb is what you make of it. If you want a tight crumb, you will shape it such that your finished product has a tight crumb, and vice versa for an open crumb. It would make sense for the orientation of your air cells to be effected by the shaping. If you shape a baguette and overhandle it such that its twisted and uneven, the air cells you get are probably going to be destroyed or torn up.
Shaping and proof have a fundamental impact on the crumb of your bread, so lets stop worrying about gluten development and worry about the whole process instead!