A rare cooked steak generally evokes two reactions from people: mouth-watering desire or sheer disgust. Cutting open the seared meat to see red liquid oozing out can be a real appetite changer.
You may be surprised, and possibly relieved, to know that the ‘blood’ you are so grossed out by isn’t actually blood at all.
During the butchering process, almost all blood is drained from the meat. If you think about the difference in uncooked meat color from pork, chicken, and beef, you will realize it is all different. That is due to the varying levels of proteins in the muscle.
The red-colored liquid you see in cow meat is actually a substance called myoglobin. Myoglobin is a red protein that carries oxygen to the muscles of the body. Myoglobin acts as an oxygen reservoir, storing oxygen when muscle oxygen levels are low, such as times of high activity.
Myoglobin is the reason particular mammal meat is referred to as the title “red meat”, where poultry and fish are considered white meat. It is because red meat has higher myoglobin proteins.
If you have ever been to the grocery store and notice the bright red color of the meat, it is for a reason. The color myoglobin provides temporary once the meat is packaged.
Meat packagers sometimes treat the meat with small amounts of carbon monoxide, carbon dioxide, and nitrogen to keep the meat lock in the bright red hue. It prevents the meat from reacting to the oxygen, which helps it to maintain color. That can give the illusion that the meat is fresh, even if it is quite old.
While the process of gas treatment is harmless to humans, it could make the age of the meat deceptive. If the meat is untreated, it will turn a gray color, which can make it less appealing to buyers.
You must admit, walking into the grocery seeing a hunk of gray meat laying in a cooler probably won’t look as yummy as a crimson steak.
During cooking, the heat also changes the chemical compounds of the myoglobin, creating a change in color. It will turn from red to grayish-brown. If a steak is cooked rare, it still has the juices from the myoglobin locked in, keeping the pink, juicy center.
Once the meat is cooked to completion, all of the myoglobin will have turned in color, and most of the moisture will have drained from the meat. That is why meat that is more well-done is tougher in texture.
So next time you want to gag watching someone cut open a medium-rare, remember it’s not real blood. Whether or not that makes it more tolerable to you is a whole other story.