What Does Gray Hamburger Meat Mean?

Many of us have had the experience of buying ground beef that looks bright red and fresh in the package, only to open it and discover it's gray in the center. Chef Thomas Odermatt, the founder and CEO of Butcher's Bone Broth, told Food Republic that the good news is the gray color doesn't necessarily mean the hamburger meat has gone bad or is unsafe to eat.

Odermatt explained, "Ground beef turns gray due to lack of oxygen. When tightly packed, the interior isn't exposed to air, causing the myoglobin to lose its red hue and appear gray or brown. This doesn't necessarily mean it's spoiled."

Time for a little science: Myoglobin is a protein found in muscle tissue that gives meat a red color when exposed to oxygen. When myoglobin loses that oxygen exposure, however, the meat takes on a gray or brown color.

So how can you tell if gray ground beef has spoiled or if it's simply lacking oxygen exposure? If the gray meat is only on the inside while the exterior remains red, it's likely fine to eat. However, if the meat is gray throughout — both inside and out — it's probably gone bad. Odermatt also advised looking for other signs of spoilage, saying, "If the meat has a strong odor and almost feels slimy, I would say it might be spoiled." He also recommended checking that the meat is still within the "best by" date on the package.

One way to prevent ground beef from turning gray inside due to oxygen deprivation is to grind it more loosely so the strands aren't as compressed. Hamburger meat is typically ground using plates with ⅛-inch holes, but chef Thomas Odermatt prefers using a plate with 3/16-inch holes. He explained that with this technique, "the meat is more loose and bears more oxygen and does not turn gray in the core."

To prevent ground beef from turning due to spoilage, use refrigerated meat within one to two days of purchase. After that, store your ground beef in the freezer. Always cook burgers and ground beef to an internal temperature of 160 degrees Fahrenheit, which ensures bacteria in the meat are killed.

You can use ground beef for your favorite burger, whether it's a Juicy Lucy cheeseburger or a classic patty melt. But if you're browning the meat instead, you don't want it turning gray and limp in the pan. To avoid that, let the ground beef come to room temperature and pat it dry with paper towels — something Odermatt also does with meat. Place the beef in a hot skillet with a little oil, making sure the pan is large enough so the meat isn't crowded. Break it into pieces with a spatula, then let it sit undisturbed for about five minutes. After that, stir every minute or so until the liquid has evaporated and the meat is nicely browned and cooked through.