The common belief that searing a steak will “lock in the juices” has been debunked by food scientists, yet some chefs persist in this practice.

Question: What are some examples of ways molecular gastronomy changed what we know about cooking?

Wylie Dufresne: There is vast sort of bodies of work that we have learned, but generally or specifically, you know, one of the famous misconceptions for years has been that searing a piece of steak, for instance, seals in the juices.  That’s how you keep your steak moist, your piece of meat moist by searing it on the outside, trapping the juices inside.  That was proven to be a fallacy by molecular gastronomy because, in fact, anytime you get something super hot, you actually begin to draw the moisture out of it rather than seal it in.  That was an early sort of wow moment I think for a lot of people.  And you still hear chefs today, unfortunately, mistakenly say, “Ah, we like to sear our steaks to seal in the juices and”...  I find myself feeling bad for them because that’s not… I understand the thought process, but it’s—it’s almost like the dark ages, in a way, that approach; that we’ve come so far in our understanding of cooking. 

I would say, for instance, what have we learned about eggs?  We’ve learned a tremendous amount about eggs.  I did not know when I started cooking that... and maybe because I never stopped to think about it, but nor was it part of my education at the time that an egg white and an egg yolk don’t cook—meaning the proteins don’t set at the same temperature.  Whites cook at a lower temperature, set at a lower temperature than yolks.  That to me is very interesting.  That has opened up, as an egg lover that has opened up sort of a world of possibilities, of applications.  

So, let’s say it’s 63 Celsius, if you want Fahrenheit, that’s 145 degrees Fahrenheit, for an egg white versus 65 Celsius, that’s about 150 Fahrenheit for a yolk in terms of cook times.  Now that only sounds like a couple of degrees, but with something very gentle, very... I guess gentle is a good word,  those couple of degrees make a big difference.  And that’s an interesting, I find, I think a very interesting byproduct of the work that molecular gastronomists are doing on any given subject.  

Green vegetables are something that fascinate chefs; the ability to keep vegetables green.  How do we keep them green?  What makes them green?  Why are they green?  And then that sort of army green.  Why do they go from bright vibrant electric green to army green, and how can we avoid that?  And that’s another element of molecular gastronomy, another by-product is that there’s a temperature range—chlorophyll is what makes vegetables green and there’s a temperature range that the chlorophyll will bleed out at.  And if you, if you go below, if you stay within that temperature range, you can fix the chlorophyll, for lack of a better term.  And when you... well no, I’m sorry.  That’s not right.  There’s a temperature range that will affect a vegetable’s ability to hold onto the chlorophyll, it will bleed out.  And so when you pass through that range, you want to pass through it quickly.  And that’s interesting.  Chlorophyll bleeds out at between 150 and 170 degrees Fahrenheit.  So you want to either be above the, or below that as quickly as possible.  You want to pass through that range.  

And some interesting experiments have been done where if you get a large pot of boiling water and you put, say broccoli in there, as long as you stay above 170, your broccoli will be green for days.  And that it will no longer be something you want to eat, but that’s useful information in terms of understanding how to make sure your vegetables are bright.  Again, as a new parent feeding my daughter you know, Gerber green beans.  They clearly did not use that temperature range as a gauge and you get this really grey, stinky green bean that is a crime against vegetables.  So that’s another thing that I think is useful to the chef and understanding what’s happened to the chlorophyll in order to keep the vegetable bright and vibrant.  And then we’re still probably going to learn more about the nutritive value and how that’s associated with the color. 

Recorded August 6, 2010

Interviewed by Max Miller