What is the criterion to classify dishes as microwaveable ones? What's the scientific reason behind this?

Question

What characteristics of microwaves determine which dishes can be used safely as microwave-ware, and which not?

Answer 1

No material that will negatively react to the microwave heating process, either by physical harm to oven or implement or contamination of food.

Answer 2

Microwaveable dishes are dishes which are not harmed by the microwave. Some plastic dishes are harmed because they would simply melt. For ceramic or glass dishes it's more to do with whether they contain materials which would heat up at different rates. For example if you have a very thick part and a very thin part, it's likely to be unsafe, since the stresses caused by heat expansion would be uneven.

If your dishes are not marked, then if they seem to be standard glass or ceramic, and are of a fairly uniform thickness, then they may in fact be safe - try using one and check afterwards whether the heating pattern seems normal (no hotspots).

Answer 3

Some of them are decorated with deposited gold lines. Those are conductive and short enough energy to cause a fire in the oven - not microwaveable.

Others are made of clays with impurities that tend to get heated by the microwaves so the plate ends up hotter than the food - not microwaveable.

Others are made from clays that are not well compressed to get the air out of them. When they are heated the air in internal bubbles expands and the plate cracks - not microwaveable.

I have never had a problem with glassware, plastic, corelle, or most typical dish sets. If plastic softens it is because of the localized heat in the food not because of the microwaves since they are nonconductors and do not heat up.

Answer 4

Aluminium foil and any other shiny-metal
like the decorative on some plates,glassisn't good for microwave, Cox, in my experience, there is some fire flash and maybe u better to never put a metal or a vacuum place with the liquid things inside it, coz when the liquids getting hot, it's volume will increase,n it will cause some pressure if they have no enough space or way to going out from their place

sorry, i can't explain this in better English

Answer 5

The criteria are:
Transparency to microwaves, (so the vessel doesn't interfere with cooking),
Heat resistance, (so the heat of cooking doesn't degrade the vessel),
Electrical Non Conductivity, (for obvious reasons).

You can test ceramic vessels, (they obviously meet the other 2 criteria), yourself:
Place the half, (water), filled vessel in the microwave and give it a short blast.
If the water heats and the vessel doesn't, its ok.

Note: Corningware DOES heat up this way, but I've found it useful for the application anyway with appropriate caution.

Answer 6

Just try any ordinary glass bowl in a microwave. It will crack. Only Pyrex glass-- heat cured, can withstand the rapid rise in temps. Likewise with plastic containers. Who wants to eat long hydrocarbon polymers with their food? And, besides, cooking in plasticware will scar or leave stain the sides of the container. Non-metal glazed, on heat-cured ceramics works the best to spread out the heat.

Answer 7

I understand that most things can be microwaved but because microwaving can change texture, looks, feel, taste etc then it is advised against by the manufacturer because it will alter your perception of the product.