Linda Arbuckle kindly submitted the following comments:

"In response to the article about microwaving…. I’ve had some stoneware cups heat up enough in the microwave to make the handle uncomfortable to hold. I find wood/salt/soda pieces are often not vitrified and have this issue, but it’s also happened with reduction-fired wares. I have heated fake bacon strips on a porcelain plate and had it crack in 2 (too much localized heat for a dense body), while earthenware baking dishes have been no problem. I do microwave Stan Andersen’s majolica plates regularly with no problems. I don’t think it’s accurate to advocate no microwaving for earthenware as a group while recommending stoneware and porcelain carte blanche. It just isn’t so. Depends on the clay body, firing, and glaze.

I daily microwave my majolica-glaze earthenware cups to make tea (they do have terra sig on the foot), and they do not explode or heat up in any uncommon way. They haven’t even crazed.

I think there’s a lot of “iffy” advice out there about earthenware. The advice on DO microwave stoneware and porcelain and DON’T microwave earthenware is like everything else in ceramics: it all depends.

So many of the pottery “sources” knock earthenware w/o really having solid facts. When I was a student, many of the high-fire gurus indicated there was nothing worth doing in earthenware, and even then, leaded was the only way. As an aside, Pete Pinnell has some interesting info on clay body strength. I’ve appended that below."