Whisk flour, cocoa, espresso powder, and sugar in a large bowl. Add water and starter, mix into a shaggy dough, cover, and rest for 30 minutes. Add salt and pinch it in.

Perform 4 sets of stretch and folds, 30 minutes apart, until the dough smooths and strengthens.

Continue bulk fermentation at room temperature for 2 to 3 hours until puffy and half again in size. Gently fold in chocolate chips.

Shape into a round or oval, rest 15 minutes, place in a floured proofing basket seam-side down, cover, and cold proof in the refrigerator for 12 to 16 hours.

Preheat a Dutch oven at 475°F (245°C) for 30 minutes. Invert the loaf onto parchment, score, and bake covered for 30 minutes. Uncover, lower to 425°F (220°C), and bake 15 to 20 minutes more until deeply cracked. Cool on a wire rack for at least 2 hours before slicing.