Why Your Microwave’s Defrost Function Doesn’t Work (and What to Do Instead)
I like having a microwave. I use mine to whip up mashed potatoes , gumbo roux , and even lemon curd . This is a universal device, and I think that everyone should have it. However, I am not thrilled with the defrost function.
How does the defrost function work in a microwave oven?
Before we get into why the defrost function in a microwave oven sucks, let’s talk about how it works. All microwave ovens are equipped with magnetrons, which are not a transformer, but a device that emits electromagnetic (micro) waves. These waves oscillate rapidly – about a billion times per second – causing the water molecules in your food to rotate at the same speed to align with the magnetic field. This rapid rotation increases their temperature and heats up your food.
According to Cook’s Illustrated , unless you have a fancy and expensive science oven, the intensity of this radiation cannot be reduced (or increased):
Here’s the catch: in most microwave ovens, because the magnetron is designed to emit a single wavelength, the intensity of the radiation cannot be changed. However, it can be turned on and off, which is exactly what the power levels do. When you lower the power level in the microwave, you reduce the amount of time the magnetron stays on.
Cook’s Illustrated further explains that microwaves “only penetrate the outer portion of food ΒΌ to 1 inch thick”, which “can quickly overheat these areas”. Turning the radiation off and on gives the heat a chance to dissipate towards the center of the food, gradually warming up the frozen piece of stew without cooking the outer layer (hopefully). But even with these fluctuations, microwave thawing has some problems.
Microwaves don’t melt ice well.
Ice is water in its solid state, but its unique crystalline structure makes it difficult to melt under microwave radiation. According to the scientists of the time , this structure keeps the water molecules from spinning, as in a liquid state:
In ice, all water molecules are combined into a crystalline structure by hydrogen bonds. These bonds stop the water molecules from spinning, which means they can’t absorb much microwave energy. This, in turn, means that the ice does not heat up.
Some of the ice will eventually melt – it’s not in the freezer, after all – and those outer liquid water molecules will begin to spin, which can lead to cooking on the outside and raw, partially or completely frozen insides, especially if you try to defrost something. at “full” power. It’s crude at best and dangerous at worst, depending on what you’re trying to defrost.
That’s why these gaps in radiation are programmed into a defrost function – they allow the heat generated by the rotating liquid water molecules to thaw their frozen neighbors.
This works well enough for some foods such as soup, casseroles, gravy, etc., but is not suitable for frozen meats. You can get by with smaller, thinner cuts, but I would never defrost a two-inch ribeye in the microwave. Even with these power outages, you will get much more radiation outside than inside. Take into account the irregular shape of the chicken breast and you have a recipe for rubbery, undercooked patches and exteriors.
The best way to defrost meat
The best and safest way to thaw frozen meat is to leave it in the refrigerator overnight. Leaving it at room temperature might be tempting, but it’s not safe, as your food will need to hang in the bacteria-loving “danger zone”. If you need to speed up the process, you can submerge the (wrapped) meat in cold water and change the water every half hour until the meat is thawed (this can take half an hour to an hour per pound).
If you’re working with thin cuts, you can use a hot water bath to thaw steaks, chops, and tenders in minutes, which isn’t enough for bad bacteria to grow. (Just remember to cook the meat right away to get it out of the danger zone.) You can also speed up the process with a submersible circulation pump . (You can also cook frozen meat in the immersion circulator – this will take about half an hour, depending on the cut.)