Why is my Ground Beef Brown inside when I unwrap it?

Some of the questions I am MOST frequently asked are:

  • Why is the inside of a package of Ground Beef darker than the outside?
  • How do you explain the colour difference between the two?
  • Do you dye your meat?

The answer is simply, pure food Science.

We have all seen this: you buy a package of Ground beef and, after arriving home from the shop you find the inside is ‘darker’ in colour than the outside?   DON’T PANIC !! The butcher hasn’t sold you bad meat, nor has he wrapped OLD Ground Beef with fresh, or added dye to it.

It turns red because it’s reacting with the oxygen we breathe not because of dye and, it turns brown in the wrapper when there’s no more oxygen to react with it.

The colour difference is due to a naturally occurring chemical reaction called oxidation. The enzymes (and iron) in the protein (meat) are reacting with the oxygen we breathe.

When meat is freshly sliced or ground, the surface of the meat is exposed to oxygen. Exposure to the air we breathe turns the meat from a dark purplish colour to a nice bright red. And, in the case of ground meat products, since the inside has not been exposed to the same amount of oxygen as the outside, the colour difference between the two can be quite dramatic.

The same holds true if you buy a large, vacuum packed beef Primal cut. The instant you open the bag, the oxidation process begins.

This is what the meat industry refers to as the “Bloom”.