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Cookbooks, TV chefs, home cooks -- we’ve all heard somewhere that we should sear meat before we cook it to “lock in the juices.” Funnily enough, that reasoning is completely wrong, but you should still sear your steaks! This misconception has been around for a really long time.

This idea might have gotten some traction in the 1840s thanks to Justus von Liebig, a German chemist who wrote about the benefits of searing meat in his book Researches on the Chemistry of Food. And we’ve actually known this to be untrue for quite some time. For example, it was debunked in research published back in 1974.

The results of that study showed that searing actually causes meat to lose more moisture, not less. In a sample of 12 seared cuts of meat and 12 unseared control samples, the ones that got a blast of heat first lost slightly more moisture -- around 3%. Similar experiments have been conducted over the years, in the lab and in the kitchen, with similar results.

Some experiments have shown no difference in moisture loss, while in others, non-seared steaks stayed a bit more moist. Either way, there’s not a huge difference in searing first vs not. It’s pretty clear that it’s not helping to keep a steak juicy.

And honestly, if you look at the surface of a steak you might notice that it doesn’t look particularly leak-proof after it’s been seared. These things do tend to sizzle. Muscle tissue contains long filaments called myofibrils.

Heating damages these fibers and causes them to lose water over time. The extent of water loss varies, and temperature plays a big part. Higher temperatures contribute to higher moisture loss, especially above 60° Celsius.

Which corresponds to about medium doneness. So if searing doesn’t lock in juices, why do we find this myth so hard to let go? We might think that seared steaks are juicier because they taste better.

We know that fat and flavor contribute to our subjective impression of juiciness. On top of that, browning meat leads to Maillard reactions, and they create a ton of flavor. The French chemist Louis Camille Maillard described the reactions in the early 1900’s.

A Maillard reaction sequence begins with the reaction of a sugar and an amino acid. After that, there are a bunch of different ways the reaction can proceed, depending on factors like temperature and pH. And it’s not just one reaction.

Many small chemical reactions are occurring at the same time, producing new flavors, smells, and creating the browning color we associate with cooking meat, as well as many other foods. So when meat is seared, the Maillard effect creates a bunch of tasty flavors. But it doesn’t “lock in juices.” That might explain why this myth has had so much staying power.

Searing might not do what we think it does, but it is a good idea. A delicious, delicious idea. If all this talk of juicy sizzling meat is making you hungry, well, you are probably not a vegetarian.

But also, maybe you’re in the mood to roll up your sleeves and get cooking yourself. So maybe you’d like to check out a culinary course over on Skillshare. Like butcher Patrick LaFrieda’s course Beef 101, where he tells you how to source and prepare individual cuts of meat.

You know, in case we REALLY put you in the mood for steak. There are over 25,000 other courses on Skillshare, so you’re likely to find something that matches your interests, from photography to productivity. The first 500 SciShow viewers to sign up using the link in the description will get a 2 month free trial, so it’s easy to try it out and start finding courses just for you. [♩OUTRO].