My fluffy sourdough sandwich bread without fats

For a lot of time I've been trying to replicate industrial cottony and fluffy white bread. I wanted a supersoft crumb without the slightest hint of gumminess (however you call it -chewy, gummy, rubbery, springy- I hate it!!) and without adding fats, not for fear of fats (who knows my passions knows how much I'm heavy handed with butter) but because industrial breads of this kind don't contain fats, so ... out of pure whim!

I decided to try a method that always guarantees softness of the crumb, but taken to an extreme: a massive poolish. I used a flour with W 300 (something like a low-end bread flour for american standards).

Preferment with

-1 tablespoon of white wheat liquid starter

-250 gr water

-200 gr flour

-1 teaspoon of honey

-0.5 gr of sodium bicarbonate

all mixed together with an electric mixer to incorporate as much air as possible. The bicarbonate is there to limit the amount of protease activity; I could have added even 1 gr  because the dough was far too slack.

The poolish fermented for 12 hours; I used it when it got covered by a thick layer of foam made of tiny bubbles.

At the end of the fermentation I added

-150 gr of flour

-7 gr of salt

-4 gr of soy lecithin

and worked the dough at very high speed (4 out of 6 in my clatronic stand mixer) until it passed the windowpane test. The dough was extremely slack, but with some stretch and fold I could shape it into a rectangle. When in shape  in a 25cm pullman pan (1.5 liters of volume) the dough reached the border in 90 minutes.

I baked at 180° starting from cold oven.

The crumb finally has the fluffy and cottony consistence I've was aiming at!

Thanks especially to txfarmer that made me understand the importance of working the dough until it passes the windowpane test.