Scalded flour is a technique borrowed from asian baking, where it is known as tangzhong or yudane. Scalding some of the flour gelatinizes the starch to make a softer, moister loaf, but if overused, can become gummy.
I’ve done a lot of tangzhong for dinner rolls and hamburger buns, but haven’t tried it for my sourdough yet! I’ll definitely be experimenting with scalding some of the flour next loaf, thanks for the inspiration!