What is stone ground flour?

It's slightly coarser than the cylinder-milled variety because the particles are less uniform in size (it's said to have an irregular grain size). Overall, it's tastier, more nutritious, and easier to digest. In fairness, it's also possible to achieve very similar nutritional and organoleptic qualities using a low-speed cylinder mill.

It's not much different from traditional flours, except that, being more irregular, the processing may vary slightly from one batch to the next, especially regarding water absorption. But it takes a little experience to get the hang of it.