After cooking a beef bottom round rump roast, a red coloring is covering, and penetrating, the meat.
The roast was purchased at a reputable grocery chain and properly refrigerated for two days before use. The raw meat appeared normal, was placed in a seasoned, 10-year-old, cast-iron pan, and cooked four hours au jus.
When the cooked roast was cut, the inside of the meat was the correct color and smelled appropriately. However, covering the outside was a strange red coloring penetrating 1/2" into the entire roast; top, sides, and bottom. The coloring did not affect the flavor.
Could someone please tell me what this coloring is? I have never experienced anything like this in my 50 years in the kitchen.
Best Answer
To quote a comment:
Here is the Science of Cooking article @Digdgeridrew mentioned
To quote from there:
Now to address why it was on the outside I'm going to make an educated guess. Per Wikipedia:
I have personally experienced this same phenomenon slow-cooking stews, roasts and even chili in the crock pot. All perfectly normal. Have you noticed when you cook red meat over high heat, like grilling a steak for example, the blood remains inside the muscle? I have noticed slow-cooking tends to "release" more of the blood content from inside the meat, likely due to more even cooking. This in my view would explain also why myoglobin would be found on the outside, rather than inside, of the meat.