My roommate has a set of non-stick pots and pans. They advertise themselves as dishwasher-safe, so we typically machine-wash them.
The exterior of the pans is not bare metal; it's covered in some kind of dark gray matte coating, as in the following picture:
However, we've noticed that the pans we use more often (and therefore wash more often) are starting to lose this coating:
The pans also give off a noticeable amount of dark gray dust if you scrub them too vigorously; I assume this is the coating coming off.
- What is the exterior coating? Why is it there in the first place?
- Why is it coming off? Are the pans not as dishwasher-safe as they claim?
- Is there any reason to be concerned about this? Does it have any implications for food safety, or for using the pans?
A couple notes:
- The non-stick coating on the interior of the pans (which is Teflon or similar) isn't coming off - it's just fine, and the pans are still functionally non-stick.
- Pretty sure that brown splotch on the exterior of the second image is just grease spillage. The pans are aluminum, so shouldn't be rusting.