Issues with larger batches of Tartine sourdoughs

Hi!

I've been reading the forums here and there for several years now, but this is my first post.

A little background: I'm the sous-chef at a small but popular restaurant where I've recently been able to take control of baking all the breads (sandwich loaves, focaccias, brioches, etc etc). Lately, since the winter is the slow season for us, I've had time to experiment with baking sourdoughs and hearth-type breads at work just as I do at home. I've had excellent results at home for quite some time, despite using totally average AP flour and an electric oven on its last legs; I've been maintaining my starter for almost three years now, and it's very happy, active and honestly loved like a pet in our house.

So, I was excited to take all that and transfer it to the restaurant, thinking that our big stand mixer, expansive work surfaces, warmer kitchen, large fridge for retarding, etc, would result in the same success and more, but that hasn't been the case.

Basically, my main issue is that I haven't been able to get the same kind of gluten development in my doughs while baking large batches at work as I do at home with a single batch, and my loaves, while delicious, don't have the same open crumb.

I've been baking almost exclusively from Tartine Bread since I picked it up in the fall (I know I'm years late to the Tartine party...) and I've been mostly baking the baguette recipe at work, though I truly love the whole wheat as well.

Here's the rundown:

The first couple times I tried at work, I baked a 3x batch of the baguette recipe. I used all Five Roses AP flour, which I believe is between 11.5-12% protein. Mixed poolish night before, in fridge overnight. I did the initial mix (pre-autolyse) in the stand mixer, thinking that this would enable me to get a head start on gluten development with the big batch. During bulk ferment, S&Fs were difficult as the dough was not very extensible (less so than at home using Robin Hood AP, a comparable flour.) By the time the dough had almost doubled, it was better, but still not quite as smooth as what I achieve at home. I was very excited; the loaves held up well during the final proof, great oven spring and then... I cut one open and... evenly-textured smallish holes. Sudden disappointment, and no one else in the restaurant could understand why, as they crammed hot buttered chunks of bread into their mouths.

I figured it was the initial mechanical mixing that must be responsible for the dense crumb, so I switched back to an all-hand method and unfortunately achieved similar results. Now, there were sometimes a few large and irregular holes, but I felt as though the dough was underdeveloped even after 3-5 hours of bulk ferment, turning every half hour. The dough is webby, tears relatively easily during preshaping, and just generally does not have the smooth, supple softness that I enjoy working with. The loaves bake up alright... oven spring is great, although I never come close to developing "ears" (and I have at home), and that dense crumb just makes me mad every time!

Recently I bought a couple bags of bread flour (12.5 and 14 percent) and have been experimenting with them at home. Brought some to work for latest batch of baguettes. No real difference, and if anything, the dough was even webbier than usual. However it was a warm day in the prep room and by the time I'd done four turns the thing had almost doubled; threw it in the walk-in cooler for another couple hours and continued but it was just never quite "right."

Hopefully someone has gotten this far through my wall of text! Here's what I'm thinking:

• maybe I'm not able to develop the dough as well with s&f in the larger batch? should I divide into two small batches after the first turn/salt addition? Or should I stay with one large batch, and retard in the fridge between turns so that I have more time to accomplish gluten development?
• maybe I'm underproofing after the final shape at work; I usually leave them an hour and a half or so, and by that time they have usually risen to about one and a half times the initial volume, but some of the "rise" is "spreading" and I get all scared of overproofing and I get them in the oven. I feel like if I waited some more, maybe those big holes would develop?
• I know my shaping technique can use some work, but I feel like the dough itself is almost preventing me from proper shaping.

Any ideas? Again, I apologize for the long post. I'll try to get some pictures up soon.