Tuesday 7 August 2012

Cooking: How To Cook Steaks with Sticky Wok and Clean Easily


Image from Locky's English Playground
Do you like my last cooking entry Cooking & Health: How To Cook Perfect Scrambled Eggs with Healthy Oil and Good Wok ? I hope so, well, this time, I'm going to share my way of cooking steaks, and I hope you will like it too.

Again, you see me using my metal-alloy wok, which sticks easily. Last time with scrambled eggs, I used the heat-and-extinguish method, but that won't work with steak. With small flame, the steak will not stick so easily but the juice will dry up; with large flame, the steak will seal the surface but the meat will glue to the wok. Use more oil? Sure, but won't you'll lose the texture when that oil fills your mouth.

Here's how I will do it:

Cooking Procedures:
  1. heat wok until it is hot
  2. add about 3 teaspoons of oil
  3. wait for the oil to start smoking
  4. place steak into the wok, let it sear one side of the steak for about 30 seconds
  5. cover 95% of the wok with a lid and add about 3 teaspoons of water
  6. Image from Locky's English Playground
  7. cover lid fully until the explosion has stopped
  8. Image from Locky's English Playground
  9. flip the steak and sear the other side
  10. Image from Locky's English Playground
  11. repeat step 5 - 8
  12. Image from Locky's English Playground
  13. remove steak from wok at your desired cook level (i.e. rare, medium, well)
  14. Image from Locky's English Playground
  15. to not to waste gravy and enjoy an easier washing task, add vegetables such as Chinese kale and fry
  16. Image from Locky's English Playground
  17. enjoy!
Fried Chinese kale in gravy (clean wok)
Image from Locky's English Playground
Medium-well Steaks
Image from Locky's English Playground
Medium-well Steaks (centre-piece)
Image from Locky's English Playground


To cook steaks in this case, you will need to understand some basic physics.
Image from Outlandish Perspectives
Facts:
  1. oil and water don't mix
  2. oil is lighter than water
  3. adding water to hot oil will cause hot oil to explode
I think everyone knows the first two and those who have tried cooking should know the third one, but how will these help preventing the steak from sticking to the wok?

The key lies on the interactions between the oil, the water, the steak and the wok.

Add water to oil
Image from sciencephoto.com

When you first heat the wok and add the oil, the oil is in direct contact with the wok. When you add the steak, the steak is now on top of the oil which is on top of the wok, when the oil turns to gas and escapes, the steak will partially stick to the wok. When you add water, because water and oil don't mix (1) and oil is lighter than water (2) some water gets between the oil and the wok (see photo above), the water quickly turns into steam and expands rapidly and introduces the Leidenfrost effect, causing "mini-explosions" (3). These mini-explosions help pushes the steak away from wok, leaving the steak "hovering" above the wok momentarily. The oil from the side gets its chance to slide back to the centre, getting back in between the steak and the wok. This process repeats as long as the water remains in the wok.

That means, the mini-explosions caused by the water and hot oil actually create a temporary non-stick wok! Magical stuff, don't you think?

Who says physics doesn't help in real life?

Have fun cooking!

Vocabulary:
sear --(vb)[T] to burn the surface of something with sudden very strong heat
hover -- (vb) [I usually + adverb or preposition] to stay in one place in the air, usually by moving the wings quickly
momentarily -- (adv) for a very short time

Resources:
Cooking & Health: How To Cook Perfect Scrambled Eggs with Healthy Oil and Good Wok @ Locky's English Playground
http://lockyep.blogspot.hk/2012/07/cooking-health-how-to-cook-perfect.html

Leidenfrost effect @Wikipedia
https://en.wikipedia.org/wiki/Leidenfrost_effect

http://dictionary.cambridge.org/dictionary/british/sear?q=sear
http://dictionary.cambridge.org/dictionary/british/hover?q=hover
http://dictionary.cambridge.org/dictionary/british/momentarily?q=momentarily+