Friday, March 25, 2005

Grilling, part 1: Use charcoal.

About a year ago, I convinced my friends Anthony and Lidia that they needed to buy a grill. But as a good friend, I wouldn't let them buy just any grill: I maintained that they absolutely must buy a charcoal grill.

Why not propane (C3H3) or natural gas (mostly methane, CH4)? They're convenient, but in my opinion, they result in inferior results. The combustion of propane and natural gas is very, very wet. The equation for the combustion of hydrocarbon fuels in air is surprisingly complicated, but here are VERY rough formulas for the combustion of natural gas and propane.

CH4 + 2O2 = 2H20 + CO2 (and a small amount of CO and H2)
C3H8 + 5O2 = 4H20 + 3CO2 (and a small amount of CO and H2)

See the large number of water molecules over there on the right? One pound of methane burning results in 2.25 pounds of water; one pound of propane results in 1.64 pounds of water.
All that water makes it difficult to get a really nice, crispy exterior on your food.

Still don't believe it? If you want to see this in action, boil a giant pot of cool water on a gas stove; notice the condensation that forms on the bottom of the pot when the water is still cool. You'll also have difficulty getting food really crisp in a gas oven. (The ideal stove has gas burners and an electric oven.)

The combustion of charcoal is even harder to characterize, since the chemical composition of charcoal depends on the particular type wood and the temperature and atmosphere it was burned in. The web page I linked to uses a simplified "C7H4O" as the formula for charcoal; I'm going with that. The important feature of charcoal is that the carbon-to-hydrogen ratio is much better, which results in a lot less water forming during combustion:

C7H4O + 8O2 = 2H2O + 7CO2 (and some CO and H2)

Much better: each pound of charcoal results in only 0.35 pounds of water. That's more like it.

If you want the best results from your grill, with the best crisping action, choose charcoal.


Post a Comment

<< Home