Why You Should Never Reheat Chicken in the Microwave, According to an Expert

Have a leftover chicken breast that you want to quick-heat for lunch? As tempting as it may be, you shouldn't zap it in the microwave.

Chicken is mostly made up of about 70-75 percent water and 20-25 percent protein, says Jacob Tuell, PhD, assistant professor at Northwest Missouri State University and member of the Muscle Foods Division at the Institute of Food Technologists.

“When chicken is cooked or reheated in the microwave, the microwaves cause the water molecules in the meat to vibrate, producing heat. Because of its high moisture content, microwaving is able to heat the product very quickly,” Tuell says. “However, as this is occurring, the microwaves are also causing changes to the way proteins are structured, which can in turn alter its texture.”

The change in proteins typically results in a tougher, more rubbery texture, compared to heating in an oven.

“These texture changes are due to microwaves altering the way the proteins fold and interact with each other, and the alterations tend to be more severe with increasing power,” says Tuell.

Chicken is typically low in lipids–organic compounds that include fats and oils. The ones present in chicken are mostly polyunsaturated fatty acids or PUFAs.

“These PUFAs are especially prone to oxidative rancidity during storage, especially in products that have been pre-cooked and stored in the refrigerator. This can result in an off flavor known as warmed-over flavor,” says Tuell. Oxidative rancidity is an accumulation of compounds that can lead to unpleasant taste or smells.

“The act of reheating in the microwave does not inherently cause oxidation and off flavors,” says Tuell. “How long the product has been stored in the refrigerator before reheating tends to be the driving factor affecting oxidation.” But pairing a rubbery texture with an unavoidable off flavor is double the reason not to microwave cooked chicken leftovers.

What About Chicken as Part of Another Dish?

Microwaving standalone chicken typically results in more obvious changes in flavor or texture than if the chicken is part of a combination dish, such as one with pasta or rice.

“If there are other flavors present as part of a dish, off flavors and odors tend to be masked,” says Tuell. “It would be similar for texture as well, where I may not pick up on those alterations when there are other textures like pasta, sauce, etcetera, that I am also perceiving.”

The Best Way to Reheat Chicken

To avoid the tough, rubbery taste and texture of chicken in the microwave, it’s better to skip the microwave and turn to the toaster oven or stovetop, says Melanie Marcus, RD, a registered dietitian and chef from the greater Charlotte area. Marcus suggests preheating the oven to 350 F and placing the chicken in a baking dish for 15-20 minutes, or until the internal temperature reaches 165 F.

If you’d prefer using your cooktop, place chicken in a pan over medium heat with a small amount of water or broth to keep it from drying out. Cover and cook for several minutes until the internal temperature reaches 165 F.

“I prefer either of these methods because they ensure that the chicken is evenly reheated while retaining texture and flavor,” says Marcus.

Tuell says most scientific research finds that there aren’t major differences between microwaving and other methods of reheating chicken, in terms of creating off flavors. The biggest issue is the hardened texture when zapping on high power.

“My recommendation would be to reheat using a relatively low power/temperature, regardless of whether you are using a microwave or conventional oven,” he says. “You want to make sure you hit an internal temperature of 165 F for food safety, but, from a quality standpoint, you do not want to go much more than that. As you increase the temperature, the alterations to texture, juiciness, and other sensory traits are going to be more severe.”