Microwaves tend to come in 2 types, ones with a rotating plate and ones without. Assuming everything else is equal about a microwave does rotating the food assist with the reheating?
The Cheese Test (youtube link) is a great way to visualize this. If the food doesn’t rotate, you end up with hot and cold spots.
(This was just the first video I could find of someone performing the test for people who hadn’t heard of it, I didn’t listen to the video, only confirm that that’s what they’re doing)
Only on microwaves that are designed to rotate food. there are designs that work without rotating but most people like to see their food go around so that is what most get.
The theory is that a rotating plate heats food evenly
In practice what ends up happening is my ceramic bowl heats to 500 degrees while the contents somehow get colder??? Except for like, one carrot that is now glowing red
Do you put the dish in the center or on the edge?
Ever since I switched to on the edge it’s noticeably improved, the bowl still gets hot but at least the food also gets kinda hot
Yes, it does. Without the plate you will get hot and cold spots where the waves interact. If you don’t have a rotating plate you should be manually rotating the food, unless there’s some new tech I’m not aware of.
Tray-less microwaves have a spinning metal “stirring fan” below a plastic floor you set your food upon to mix the bounce path the microwaves take. Since they expose fewer moving parts to the end user they are easier to clean and more resilient making them a good option for commercial / high volume settings.
Interesting, thanks!
I haven’t seen one for sale in a few decads though. Where can I get one?
A microwave works by bouncing microwaves around the interior. Since the shape of the container doesn’t change neither will the path that the bounced waves take. This can lead to hotspots in what you’re reheating.
To mitigate this you have a few options:
- move the food around in the container so that different parts pass through different hotspots over time (this is what a tray does)
- interrupt the microwave path via a “stirrer fan” that sits below the microwave floor (this is what tray-less units use)
Both approaches redistribute the hotspots to maximize even heating. The efficacy of either approach will come down to the specific design of either unit, but a tray-less unit can be easier to clean, and with fewer moving parts exposed to end users can be a good option for commercial/high user count settings.
Each design accomplishes the same task of relatively even heating with few hotspots.
As others have said, microwave ovens create standing waves with regions of higher power (hot spots), which unevenly heat food. If you want to see this for yourself, Scientific American has a kids project for measuring the hot spots in a microwave using chocolate or marshmallows. There’s also a bunch of videos on YouTube of people essentially doing this same project.
As long as you don’t put it in the center, yes.
I always forget that. Instinct is to put things in the center.
Even in center it will work given that the time you are heating isn’t tiny.
The center is the least optimal place for even heating.
It makes the heating more even. The microwaves aren’t uniform inside so rotating helps even things out.
I had a microwave that moved the plate side to side which worked really well for heating anything solid, but heating liquids usually resulted in a mess.
Do they still make non rotating microwaves?
Yes, commercial and maybe some premium microwaves can achieve the effect of the turntable by more hidden means.
Though, I don’t know if they still make cheap microwaves without any hotspot mitigation whatsoever.
I had a square one so without a rotating plate, IIRC it was the microwave emitter that rotated instead. If that is plausible, I sort of doubt it a little now.
At least one brand now has a newer design that rotates the microwaves themselves to better distribute the energy. It’s a bit pricier than the standard models.
I only use the most expensive of microwaves that rotate the actual causal reality of the earth-itself around the microwave.
