Whether a bloody cut of beef grosses you out or excites your inner carnivore, it’s worth knowing what that "blood" is really made of. According to this video from Tech Insider, it’s not blood at all. It’s actually a mix of water and myoglobin—a protein found in animal muscles.
If you buy your steaks fresh from the butcher, this red juice, called "weep" or "purge," should be missing from your meal. That’s because the liquid is a byproduct of the freezing process: Water in the meat swells into ice crystals, puncturing the muscle cells around them and releasing red myoglobin. This protein is abundant in animals with lots of active muscle tissue, which explains why you won’t find the red liquid in poultry products.
Feeling hungry? Here’s a tip for making your burgers extra juicy (not bloody).