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It's kind of unavoidable if you cut into a big juicy rare steak
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You're gonna get some juice. Watery, red liquid seeps out of the meat and on to the plate and it kind of looks like blood.
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But I have good news for people
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who like to eat red meat but don't like to eat blood
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It's not blood.
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It's just water plus a handy protein called myoglobin.
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All meat is muscle but the muscle looks different
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depending on what it's used for
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White meats like turkey and chicken come from muscles
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that are used in short spurts every so often
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but have to get moving quickly
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Think of the chicken breasts
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They don't actually use their wings very often
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Red meats like beef, lamb and even pork come from muscles used for long strenuous activities
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like carrying a huge cow around all the time
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Before cooking,
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these meats are a pinky, reddish color.
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Holding up a heavy cow is some serious work.
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Work that requires a lot of oxygen for fuel
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which is where myoglobin comes in
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Myoglobin is a special protein
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with an iron atom at its center,
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which bonds with, then stores and delivers oxygen to muscle cells
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It works together with hemoglobin, another oxygen carrier
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to get oxygen to the cells that needed.
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The difference between red meat and white meat
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comes from the levels of myoglobin in the muscle.
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And myoglobin protein itself is red
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so the more myoglobin in the cells the redder the meat appears.
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And that juice that's spilling out of your meat?
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That's a combination of water and myoglobin.
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The animal's blood was removed when the meat was processed.
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Beef is around 0.8% myoglobin and lamb has a little less at 0.6%.
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And all of those ads have been lying to you
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because at 0.2% myoglobin
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pork is generally considered red meat too.
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Chicken only has about a quarter of that amount
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But what about humans?
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Well, our flesh is about as red as red meat can get
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at 2% myoglobin.
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If you have been like steak
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but you don't want red juice
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you have options.
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Myoglobin is red when it's bonded with oxygen.
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When meat is cooked rare,
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up to about 60 degrees Celsius,
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the color stays
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Above that temperature,
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the iron atom in myoglobin loses an electron,
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and therefore its ability to bind with oxygen.
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Instead, the myoglobin forms a new molecule
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called hemichrome
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that gives medium and well done meet its brown gray color
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Myoglobin will also turn brown
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if it's exposed to air for long enough,
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because that makes the iron atoms lose an electron too.
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Which is why checking the color
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can be a handy way to tell
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if your store-bought meat is still fresh
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It doesn't always work though,
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because some meat producers add compounds
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that keep the meat red and the color can last way past the expiration date.
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But if you do end up buying that red meat and cooking it rare,
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I hope you enjoy your oxygen rich protein water.
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Thanks for asking and thanks especially to all of our patrons on Patreon who keep these answers coming
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or get these quick questions a few days before everyone else
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go to patreon.com/scishow.
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