Exercise in crumb texture

Can we get nice crumb texture quick? As an excercise, 75% hydration bread was made with one cup of water and bread flour (+ yeast and salt) and kneaded 30 min. in a cheap bread machine. It was risen 30 minutes, covered, at room temperature, stretched and folded a few times, and then baked 30 min on a preheated (to 500F.) compound masonry slab.

squatbread.jpg, 41888 bytes

The following images were obtained by placing a slice on the platten of a scanner, and scanning. The second image is an enlargement of a portion (indicated by a red rectangle) of the one immediately below.

slices.jpg, 44574 bytes crumb.jpg, 51261 bytes

Well, I think I know the answer already, but next time, for bigger holes, I may try a second stretching and folding after the rise, and add a second rise after that. After that, I will see if I can apply a similar technique to sourdough.