1) An internationally respected research institute dedicated to upgrading food production and resources for third world countries extensively researched the effectiveness and viability of grain mills with both stone plates and those with iron and steel. Their recommendation, without reservations, iron or steel over stone! Why? Primarily because of the grit and particulates left behind by some grinding plates. I saw numerous pictures of skulls, both old world and new world, with the teeth worn completely away. Researchers say the total destruction of the teeth was the result of eating stone ground grains.
2) A variety of stones have been used as grinding surfaces for grain and food mills - often whatever stone has been available has been the "stone of choice". I have even seen sandstone grinding plates. Unfortunately, for the millions of molars that have masticated stone-ground flour over the centuries, particulates break away from the grinding surface quite easily. Also, Mother Nature is not always consistent in the stone-making department and she doesn't discriminate against such things as lead and arsenic seeping through the ground water or existing in the stone itself.
3) My next step in searching for the perfect grain-grinding surface led me to a major manufacturer of stone grinding wheels. "What are man made stones manufactured from?," I asked. "Aluminum Oxide plus binders", was the answer. Aluminum has long been linked to a woeful list of ailments - dreaded Alzheimer's is the latest. Ingesting aluminum in powdered form in your bread and pancakes is about as smart as eating slug bait for breakfast. Yet I and thousands of others have done just that because of the misinformation that's rife in grain grinding lore.
4) The coolness of the grind is often dependent on at least two factors:
- How efficiently the grinding surface works
- The speed of the mill
- A superior design means a cooler grind.