Does anyone know the optimal time to steam or humidify the dough after loading in the oven? We are having discussion about this on another forum and I had hoped to find a professional baker's answer to this question. Do you wait a minute or two to let the skin form over the dough or do you spray right away?
Spray right away - you are trying to gelatinise the surface starch.
If you wait until a skin has formed and its already hot its too late.
IMHO steam after the first minute or two has little effect. Indeed you wan to vent the oven in the last half of the bake for a crisp crust.