To understand what happens when you microwave something for too long, it’s useful to first of all have an idea of how a microwave actually works.
In very simple terms, your microwave generates energy waves. This energy then agitates the water molecules of the food you’ve placed inside the appliance, which then spreads to the rest of the food.
That explains how microwaves both heat food quickly and efficiently, and also why there are certain food types that really aren’t compatible with this cooking method.
What happens if you microwave too long, then?
Well, in simple terms you’ll heat those water molecules to an exceptionally high degree, which will dry the food out. Leave it too long after that, and you risk causing damage to the microwave itself – and your microwave only has so much life expectancy in it.
The Effects Of Microwaving Too Long
If you microwave a certain type of food for too long, you’ll effectively burn it. Others are fine with a longer cook, and in fact some meals can be microwaved for 30 minutes or more.
We’re all familiar with what burnt food looks like on a stovetop, but it’s a little different when it comes to the microwave.
You can think of microwave ovens in terms of cooking food from the inside out, rather than the other way around on a stove.
If it’s cooked too long, at too high a temperature, you’ll find blistering hot spots in certain areas, and cooler spots in others. This is the reason why you’re so often advised to stir the contents during the microwaving process.
Before that happens though, you’ll simply dry the food out completely, making it extremely unappetizing.
How To Avoid Problems
The easiest way to avoid microwaving something for too long is to simply follow the instructions properly.
That’s easy enough to do with a microwave meal, where the instructions for cooking and stirring are clearly marked.
These have been tested by the manufacturers on multiple microwaves, and they have a good average in mind.
Be aware though that there’s a lot of heat left in your food once you remove it from the microwave.
If you’re not following packet instructions, I recommend taking your food out of the microwave a minute or so before the standard cooking time.
While the food’s resting, it’ll still cook and potentially dry things out. If you’ve cooked for the standard time and left it resting while you attend to the rest of the meal, you’re effectively over-cooking it.
Not only does this make the food less pleasant to eat, you’re also unnecessarily baking away some of the nutritional goodness – especially relevant when you’re prepping veggies.
Microwaves & Nutrition
Let’s bust a myth or two about microwaving vegetables – and other foods – while we’re at it.
There is nothing about the particular process of microwaving food that removes nutrients. You lose some vitamins from the food when you heat it up, but that applies to all cooking methods.
This is a trade-off, of course, because certain foods need to be heated enough that you eliminate any bacteria that may be lurking.
It’s all a bit of a balancing act really. You need to heat the food enough to remove any bacteria, but not nuke it so hard that it turns into an unappetizing mess!
As for microwaves though? They’re perfectly fine to use for both initial cooking and reheating, and they remove no more nutrients than your oven or stovetop.
Striking The Right Balance
Overcooking is just one part of the problem when it comes to working with microwaves. You also need to make sure that the heat is evenly distributed throughout the meal.
As I mentioned earlier in this article, a lot of the jobs we use our microwave for come with instructions. They’ll explain power settings, timings, and stirring points.
Don’t deviate from these – the food manufacturers know what they’re doing when it comes to getting optimal results!
When you’re working with your own raw ingredients though, look for cooking guidelines online from a reputable source.
You’ll still need to tweak the timings to suit your exact make & model of microwave, but pay attention to the end results.
If things come out too hard, cook a little longer. If things are mushy, reduce the cooking time in the future, and allow them to cook a little extra while standing.
As long as you’re not working with bacteria-prone food types, you don’t have to follow recipe instructions blindly.
Extra Tips For Better Microwaving
Here are some extra tips for getting better results from your microwave – however long you run it for.
Place The Food Properly
Microwaves work in a very particular way, and that means you need to position your food inside accordingly.
As a general rule, you should position the thinnest parts of the meal towards the center of the container, and the thicker parts around the circumference.
This plays into the way that energy is distributed around the microwave, and will ensure you don’t microwave any part of the meal for too long.
If your meal is a bit of a mish-mash of ingredients, just make sure everything is evenly mixed before spreading it around the container or plate.
If you don’t do this, there’s a good chance you’ll notice hot or cold spots developing. No one wants unevenly heated microwave food.
The easiest way to ensure everything is evenly heated – without being over-heated – is to stir the contents regularly.
This will spread the heat and the moisture around your food, reducing the overall amount of cooking time that’s required. That, in turn, reduces the risk of running your microwave too long.
Make sure the turntable platter can rotate freely as well! Microwaves need to spin in order to achieve even heat distribution, so make sure it’s seated properly on the base of the microwave.
Tweak The Cooking Time & Power
Make sure you’re using the right amount of power for the right amount of time.
If your food isn’t cooking through enough, increase the power next time. If that’s still not right, tweak the cooking time.
If it’s overcooked, reduce the power next time and keep the time the same. Again, you can tweak the timings on your next attempt.
I keep notes on everything I do in the kitchen. In the case of my microwave, I know just the right power and time settings I need to get precisely the results I want.
Microwaving Frozen Food
When you’re reheating things like frozen soups, leave it out on the side for an hour or so before placing it in the microwave.
It’s really important you’re able to easily stir this sort of thing while it’s cooking. A little bit of time on the countertop will start loosening up that iciness, which will make it much easier to mix.
Now you know what happens if you microwave too long! At best you’ll have unpleasantly dried-out food. At worst, you could damage your microwave if you really go nuts.
If you follow the advice included in this guide though, you’ll be able to strike just the right balance between cooking power, and cooking time.
Always follow the instructions that come with a pre-made product! Otherwise, factor in the resting time of your microwaved food, and make sure everything’s well-positioned in the appliance, with lots of stirring if the food requires it.
Mark’s a lifelong food fanatic and spent ten years working as an entertainment journalist. He now combines his love of food, drink and writing as the founder and editor of Viva Flavor. Read more