We’re an instant society these days. With email, texting, cell phones and Instagram (don’t really understand this one) people want things right now. This includes their food. Microwave ovens are as common place in most kitchens as the coffee maker and toaster. They can help with this “instant” society and cook food quickly.
However, if you’re trying to defrost food in the microwave it’s going to take a little patience. It isn’t going to happen instantly—but you can be successful with very acceptable results.
To understand how microwaves defrost you must first understand how they work. Microwaves are invisible high frequency radio waves that cause water molecule in food to vibrate. This causes “friction” that produces heat within the food. Microwaves do not penetrate deep into the food, so the interior of the food is heated by conduction—the heat from the outside moving into the center. Understanding this concept, you can immediately see why defrosting something in the microwave can be problematic.
How can you make it work?
Check the power levels. Defrosting takes time and the defrosting time will depend upon the amount of food, the shape of the food and the density of the food. Defrosting is usually done at a lower power (30% or 50% of full). If your microwave does not have separate powers or a “defrost” setting you can “simulate” this by turning the microwave oven on for a short period of time, allowing for an equal or double amount of standing time and then turning on again and repeating. Trying to defrost on “high” will just result in overdone outsides and frozen insides.
Standing time is also essential. Heat continues to travel to the center of the food even after the microwave shuts off. This allows for even heating of the food. Not allowing for standing time frequently results in over cooking. This is why frozen packaged foods usually directs you to allow the food to “stand” for several minutes before serving.
Don’t be impatient when defrosting. It takes 3-5 minutes on defrost (or low or 30% power) in the microwave oven to defrost one pound of frozen ground meat. But you also need to allow for 5-10 minutes of standing time for the process to be complete. Don’t get impatient and put it back in and zap for a couple more minutes—that’s when you get cooked, dried edges.
The shape is important. A trick I like to use is freezing foods in a “donut” shape. If you have an option, freeze ground meat, casseroles or even leftovers without a center. The middle of the frozen food is the hardest to defrost, so by freezing with a hole in the middle you eliminate that problem. The hole allows the microwaves to enter the frozen food from the center as well as the outside. Also, for quicker defrosting, when freezing foods try to keep them 3” thick or less.
If freezing in a “donut” shape is not possible, turn, stir or break-up the food as soon as possible to allow the heat to evenly distribute through the food for quicker defrosting.
Also keep food safety in mind. Once you defrost something in the microwave you need to finish cooking it immediately.
Cheryle Jones Syracuse, MS
Professor Emeritus, The Ohio State University
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