Is that Blood on the Plate?

You might think so, especially with rare steak still sporting a red, almost blood-like colour. But the answer, surprisingly enough, is no, it isn't blood.

The moment cattle are butchered, all the blood is drained from their bodies. So, when you get your hands on a raw steak at your local butcher's or supermarket, there's virtually no blood left.

So, what's the red stuff?

It's actually something called myoglobin. Myoglobin is a protein that resides in the muscle tissue of many animals, including our bovine friends that provide our beloved steaks. This protein's job is to carry and store oxygen in muscle cells. The protein can bind oxygen and keep it ready when the muscle needs to act.

The myoglobin in the steak is a deep purple colour when raw. But you know how the steak goes from red to pink to brown as you cook it? That's the myoglobin reacting to the heat. When the steak hits your grill, the heat changes the myoglobin's structure. This structural change also causes a colour change, and that's why your steak changes colour as it cooks.

When you see juices seeping out of the steak as it cooks, you see mostly water. As the myoglobin changes colour, some dissolves in the water inside the steak. This combination of water and myoglobin forms the juices that seep out as the steak cooks. It's not blood but water and myoglobin.

You might also find some of the juices from your steak are a bit fatty. As the steak cooks, any fat within it begins to melt. Some melted fat can escape and mix with myoglobin-filled water, making the juices more flavourful. This mix of fat, water and myoglobin gives your steak its mouthwatering aroma and flavour.

Interestingly, the amount of juice that comes out of your steak and the colour of those juices can vary depending on how you cook your steak. You might've noticed that a well-done steak doesn't have as much juice as a medium or rare steak. That's because the longer you cook a steak, the more the proteins, including myoglobin, squeeze out water.

When you cook a steak too well done, almost all of the myoglobin has changed colour, and much of the water has been squeezed out. This is why well-done steak is drier and doesn't have as much of a red or pink colour.

On the other hand, if you cook a steak to rare, you're only heating it enough to start the myoglobin denaturing process but not enough to finish it. This leaves plenty of myoglobin in its original state, giving the steak that deep red, rare colour. Plus, because you're not cooking the steak for as long, you're not squeezing out as much water, leaving the steak juicier.

So, there you have it, a bit of a deep dive into what's happening when you cook a steak.