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Surprise -- it's not blood.

We've all seen that red liquid that leaks from steaks we buy in the supermarket. You've probably just assumed it was blood, but, like the old saying goes don't assume because you make an "ass" out of "u" and "me."

This video from the good people at Tech Insider peels back the curtain by letting us know the liquid is actually a combination of water and the protein myoglobin and referred to as "weep" or "purge," which is a name you're probably not familiar with because, really, how appetizing does a food that contains weep and purge really sound?

When the meat is frozen the water expands and turns into ice crystals. When the thawing process starts, some myoglobin also defrosts and appears red because it has iron in it.

So, now you know and, more importantly, you have a nice piece of info to share with people while attending all those barbecues this summer. You're sure to impress everyone more than the grill master who hands you a black hockey puck that you were hoping was going to be a nice tasty piece of flank steak.