Microwaves and Tableware
Most kitchen ceramics are designated "microwave safe" but,
increasingly, users of ceramics in microwaves can experience the
item heating up. The following is some basic information about microwaves
and ceramics that will hopefully shed some light on the issue.
Microwave safe - Microwave safe means it’s safe to use the
product in a microwave without hurting the oven or having the product
immediately harmed in some way. It does not mean the item will not
Why do some items get very hot when micro waved? Probably because
of moisture trapped in the body of the ceramic and the moisture is
being heated by the microwave process. In very rare instances, after extended time in a microwave (multiple minutes), certain ceramic items can actually give off a vapor or
steam and become very hot. These items are no longer microwave safe.
Does microwaving hurt ceramics? If you have a ceramic item that
noticeably heats up in a microwave, the life of the product is probably
being shortened by microwave use. The item has some moisture in the
body and the moisture is reacting to the microwave process. This
is essentially a heating/cooling cycle (think expansion/contraction)
and will eventually lead to "crazing" of the glaze. Crazing is when many
fine lines appear in the glaze.
Does all ceramic tableware get hot when micro waved? Eventually yes. We have done extensive testing at our office with a wide range of different items from different manufacturers and they all reacted pretty much the same which is to say they heated up.
In conclusion - since all ceramic tableware reacts to microwaves by heating up, this cannot be considered a defective condition. Common sense handling of potentially very hot dishes after long stints in microwave ovens is the order of the day. Frequent exposure to microwaves may shorten the life of ceramic dishes and cause crazing of the glaze.