The oil application helps to seal the crust surface from the air, thus reducing the oxidation of the dough on the surface. This is why we feel that it may be caused by oxidation rather than drying of the dough. For some unknown reason to me, we have seen what we feel is a reduction in those blisters when higher dough absorption levels are used, or put another way, lowering the dough absorption seems to make the situation worse. The one next step that I would suggest is to increase the dough absorption by a minimun of 2% of the total flour weight: flour weight X 2 (press the “%” key) and read the amount of additional water to add in the display window. Keep in mind that you might need to do this more than once. Another thing is to look at your flour bag and read the ingredient label to see if the flour is bromated or not. If it does contain bromate, you might want to ask your supplier to get you a bag of the same flour, but without bromate to try. Bromate (potassium bromate) is an oxidant that is added to some flours by the mill to further strengthen the flour. In pizza production, we really don’t need this extra strength, so you shouldn’t see any ill affects to the dough, but by removing the bromate, you might also get rid of the blisters. Let me know what you find out.
Tom Lehmann/The Dough Doctor