This interview was originally broadcast on May 22, 2001.
Eating out has taught many Americans to be knowledgeable about ordering subtle and complex dishes from around the world, but it's left many of us less knowledgeable about how to cook our own food. That's one reason food writer Russ Parsons decided to write How to Read a French Fry: And Other Stories of Intriguing Kitchen Science, his book about the science of cooking.
Parsons joins Fresh Air's Terry Gross to answer all sorts of food science questions, including why meat browns, why sauces emulsify and how frying is different from roasting. Among the other nuggets of wisdom he shares:
Why onions make us cry: "In the water in the onion there are these little vacuoles — they're little pockets of different chemicals. When you cut an onion, all those vacuoles are disrupted, the chemicals empty out, and they begin to combine with each other. You get these chemical reactions. ... After the fifth or sixth generation of combining and recombining, the result is a kind of a sulfur gas, and, actually, it's not clear at this point whether the sulfuric gas goes up your nose or goes directly to the eye. But either way, it irritates you and it makes your eyes tear as a result of that. And the great thing is that the chemical name for those chemicals are lacrimators from the Latin word for tear, lacrima."
Why frying is different from other forms of cooking: "The special thing about frying is that in most kinds of cooking, whether you're talking about roasting in an oven or boiling in water, the cooking medium doesn't change very much. The water stays essentially the same, the air stays essentially the same. ... With frying, both the oil that this food is being fried in and the food are changing all of the time. ... As the frying progresses, as the oil is heated and more things are added to it, the oil begins to break down. One of the byproducts of this breakdown is chemical 'soaps'. ... They allow the cooking oil to penetrate that water barrier so that the cooking oil comes in direct contact with the food that's being fried so that it browns it better and it cooks it through more thoroughly."
How to pick the best fruits and vegetables: "This is almost embarrassing — the really simple answer is that the fruit or the vegetable that's heaviest for the size is going to be the best almost invariably. ... One of the things that happens after fruits or vegetables have been picked, they continue to respirate and they continue to give off moisture. ... So if you pick the fruit or the vegetable that's heaviest or that looks the most like it has the most water in it, you're going to be a lot better off."
Why dark meat is dark: "Chickens will fly if they're provoked, but they don't fly very often and they don't fly very far. But they do walk around a lot, and so the leg muscles tend to be much more developed than the breast muscles do. What happens when the muscles are more developed — the reason that the meat is darker is because there's more blood circulating to it because of the exercise, but also there's more connective tissue. Connective tissue ... if it's not cooked it can be stringy. But when it's cooked all the way through, it actually acts as a lubricant that makes the food juicier."
Russ Parsons is the food editor and columnist for the Los Angeles Times. He is also the author of How to Pick a Peach.