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August 1, 2004

Hot wok, cold oil

When I was a young lad, I got hooked on watching cookery shows. At that time, we only had one Star TV channel, but much to my delight, they showed a different cooking show every afternoon. One of my favourites was The Frugal Gourmet by Jeff Smith (who recently died, unfortunately). One of the first cooking principles I learnt from him was "hot wok, cold oil; food won't stick" (A wok is a Chinese frying pan; a beastly version of our kadhai). This simple piece of advice can dramatically improve your cooking. It certainly made a difference to mine!

I've watched plenty of friends and family cook dishes at their homes, and one of the most common mistakes is to not bring the frying pan or cooking vessel to the correct temperature before adding oil. If you add cold oil to a pan that's not hot enough, you will lower the temperature of the pan even further. When you then add your seasonings or other ingredients, it will no longer fry. Instead it will soak in the oil.

When an ingredient soaks in oil without frying, it has many nasty side effects. First, because the oil isn't hot enough to sear the outside of the meat or vegetable, it gets absorbed into the food, making for a greasy dish. Second, food will stick to the pan more. (More about that shortly.) Lastly, you won't get the texture you want.

When a wok is hot enough, adding oil on top of the hot metal create a thin film of oil that goes into the pores of the metal, creating a "non-stick" effect. The oil then dances easily on the surface. You will now have to use less oil to saute or stir-fry your food.

So how exactly do you know when your wok is "hot enough", you ask? No, you don't have to keep a thermometer handy. Some simple guides will do the trick - what Asians have been doing for ages.

How hot your pan should be depends on what you're using it for. If you're making a typical Asian meat stir-fry, you need it very hot so that the meat is seared as soon as it touches the pan. If you're stir-frying veggies, it doesn't have to be as hot as that. If you're simply pan-frying something that needs about 10 minutes in the pan, you need a medium to medium-high heat.

My method for determining these temperatures is surprisingly easy and needs something very commonly found - water. And only a few drops of it to sprinkle into the pan. Start by heating the pan for about 30-60 seconds on a medium-high flame. When you feel it's time to check the temperature, simply run your fingers under a tap of water. Then take your hand and quickly snap your wrist so that the residual water falls into the pan. The reaction of water on the pan can tell you how hot your pan is. Here's a key:

Water doesn't sizzle audibly and stays as drops on the surface: Unless you want to make scrambled eggs, your pan is not close to being hot enough.

Water starts sizzling on contact but doesn't evaporate immediately: This is your medium heat. If you wait for the water to boil off, you'll have a pan suitable for sauteing or for stir-frying vegetables.

Water sizzles loudly on touching the pan and boils off almost immediately: Ah, this is what you need for stir-frying. Add your oil and swirl it around and you'll see how easily it glides. You've now got a fine surface for cooking food without it sticking too much. Strips of meat added to the wok will now get seared instead of getting "stewed". That makes all the difference to texture and taste in a stir-fry. (A detailed article on stir-frying will come in the future.)

The water trick I've explained is an excellent technique to get the texture that you want from dishes. They will also reduce the amount of oil you need to use in dishes. Remember that once you add food to a pan, you bring the temperature of the pan down drastically so you have to turn up the flame for a short while as necessary to maintain the temperature you're looking for.

I hope this tip comes in useful in your cooking. I welcome feedback, so please use the "comments" link below to share your thoughts.