I've got a microwave container and no oven and looking to cook some stuff - is it possible to microwave a container that's marked as microwave safe for 40 minutes or so?

  • What do you need to microwave for 40 minutes? The longest I ever use the microwave is about 15 minutes for vegetables. Apart from that, I imagine that a microwave safe container will be ok - if I put the same container in the microwave for 3 minutes every working day for a month, then the container will have been inside for 75 minutes. Commented Jan 4, 2012 at 7:55
  • 3
    It takes ALOT less time to cook in the microwave compared to the oven. Please do not use the same time it would take to cook something in the oven and convert it 1 minute - 1 minute in the microwave. That would be disastrous. For example, it takes about 2.5 minutes to microwave a hot pocket while it takes about 20 minutes in the oven. If you microwave that hotpocket for 20 minutes, you're going to get a radioactive lump that will probably have a pulse of its own.
    – Jay
    Commented Jan 4, 2012 at 20:21
  • Potatoes, apparently - I gave it a go yesterday and haven't died yet so I guess 40 minutes is okay at least once - the container didn't warp or anything which is a start.
    – Blakomen
    Commented Jan 4, 2012 at 22:53

1 Answer 1


A microwave-safe container shouldn't be heated significantly by the microwave (only by conduction from the food it contains). So, it should be fine, so long as the food is, and as long as the food doesn't exceed its allowable temperature.

You can test fairly easily—put the container, partially filled with some water, in the microwave for a few minutes. Does the container heat up, possibly more so than the water—especially where its not in contact with the water? If so, I'd be reluctant to use it in the microwave for that long.

Some containers are microwave safe, but only for heating to maybe 160°F or so. A common example is LDPE (often used for plastic wrap). Some can't take boiling for more than a short time (e.g., HDPE). Polypropylene should be fine, even with boiling. Go any hotter (e.g., filled with oil, which is probably insane) and most will fail. If you're lucky, the container will have a resin ID code on it, LDPE is #4, HDPE is #2, polypropylene is #5.

Your microwave may not be fine with 40 minutes of strait microwaving, or with the steam buildup. You should probably check its manual.

I assume also you've read Jay's comment about converting recipes, and that you're doing something where 40 minutes won't result in charcoal.

  • make sure you are not cooking oily food in plastic for long - oil drops on plastic can form hotspots capable of melting a hole in! Commented Nov 1, 2016 at 17:26

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