Tuesday, April 1, 2008

Conventional vs Electric vs Induction

I'm talking about hobs here, conventional or radiant hobs being the oldest technology and induction cooktops being the new kid on the block.

Conventional hobs burn a fuel, usually liquefied petroleum gas which comes in the huge compressed cylinders delivered to your home by the friendly union gas or esso uncles or natural gas if your house is hooked up to the power gas network. I have 2 issues with gas hobs, the 1st being lack of control and the 2nd being the very fact that it isn't very environmentally friendly.

At home, I used to have problems because i could never get my griddle hot enough to sear my meat cuts properly, this is an extremely important step when preparing roasts and tataki dishes. I insisted on getting one of those high pressure zhi char burners when i moved to my new house but ended up burning most things to hell and back with it. At work, i had similar problems. If i wasn't burning the berries i was trying to saute, then i would definitely be toasting my arm while reaching for the pans on the inner burners. That's one reason why chef jackets are supposed to be long sleeved, to protect your forearm from radiant heat and spillage. I'll admit that it's probably my own lack of skill that results in the burning but that still doesn't change the fact that i cannot serve out burnt crap.

burning off the joy juice in a red wine reduction

My only experience with electric coil hobs was in Europe. I think they have the impression that piping or storing gas was a safety hazard and many places are so old that induction cookers weren't invented yet or perhaps too expensive to install. Anyway, the studio apartment i stayed in while in Munich was really tiny and the kitchenette which was by the door had 2 electric hot plates which took forever to heat up. Boiling water soon followed this routine, i'd get up from bed and crank the hot plate to max, fill a pot of water, put it on, have a bottle of weissbier dunkel then proceed to take a dump. After which, my water would just be coming on to a gentle boil. Magnificent... Well, i got used to it after a while and churned out some pretty decent dishes.

mushroom ragout with freshly grated parmagiano

pork schnitzel, potato mousseline and rucola aglio olio

truffled eggs

hokkien mee

I had to sms my best friend all the way back in Singapore to ask him if hokkien mee had bean sprouts because i forgot. Turns out that there are bean sprouts in the dish but i left them out because they cost a whopping 5.50 Euro a kg there which is more than a hundred times the price here at home.

Finally we come to induction hobs. This is without a doubt the kitchen technology of tomorrow. When choosing hobs for the kitchen at the Screening Room, i saw a demonstration of a commercial induction hob bring 3 litres of water to a full boil in less than 5 minutes. I swear, it was love at first sight. The efficiency of induction hobs is also unparalleled, not only does it use electricity that can be generated from renewable sources, it can also be up to 84% efficient as compared to gas burners which are only about 40% efficient.

So what makes this baby tick? Here comes the good part, as an undergraduate reading materials science, i can say the following with great authority ;). The underlying principle of induction cooking is magnetic hysteresis. An induction cooker element is basically a high power, high frequency electromagnet that generates a finely tuned electromagnetic field in the region of space surrounding it(1). When a ferromagnetic cooking vessel is placed in this field, heat energy is induced in the vessel through hysteresis which is a measure of resistance of a material to magnetization(2). It's basically the same concept as an electric heating coil but induction cooking uses magnetic resistance instead of electrical resistance to generate heat. The heat created is transfered to the contents of the vessel(3) and nothing outside the vessel is affect by the field(4).

This results in a few noteworthy points:
- Heat changes are instantaneous making induction settings very precise.

- The heat is generated in the cooking vessel itself and hence the hob only gets as hot as the pot.

- Only ferromagnetic materials can be used on induction cookers i.e. cast iron, some stainless steels and a few magnetic ceramic materials. Pyrex, aluminium and copper cannot be used.

- Nothing outside the vessel is affected by the field. This implies cool stovetops and cooler kitchens. No more sweat dripping into your food!

The loss of an open flame does mean that you lose ability to char foods but this can be done in an oven. As for Asian dishes that need the 'wok hei' like fried rice and hor fun, my personal solution would be to have a seperate standalone zhi char burner specifically for that.

I only know of one restaurant that uses induction hobs and that is in the Western kitchen at the Top Table at the Temasek Culinary Academy. They chose induction for safety reasons.

The Top Table

Temasek Culinary Academy
Block 31, Level 3

Operating Hours
Weekdays (During term time): 11.30am - 2.00pm (last order)
Saturday, Sundays, Public Holidays, Vacation, Test and Exam Period: Closed

Phew.. What a hell load of typing that was.

Till next time!


toxiferous said...

Those pictures look great. I especially like the first one where you're burning off the alcohol in the red wine reduction. :)

Fidei Defensor said...

Thanks! Do come back for more. I have tons of photos that I want to put up.

Anonymous said...

i.love.induction.hobs too!
fell in love with them in adelaide! (:

Anonymous said...