Cooking for Geeks: Real Science, Great Hacks, and Good Food (29 page)

PHOTO OF HAROLD MCGEE USED BY PERMISSION OF KARL PETZKE

Harold McGee writes about the science of food and cooking. He is the author of
On Food and Cooking
(Scribner), described by Alton Brown as “the Rosetta stone of the culinary world.” He also writes a column, The Curious Cook, for the
New York Times.
His website is at
http://www.curiouscook.com
.

How do you go about answering a food mystery?

It depends on the nature of the mystery. It can start with and mainly involve experiments in the kitchen, doing a particular process several different ways, changing one thing at a time, and seeing what the effect is. Or it can mean going to the food science or technical literature and hunting for information that might be relevant.

A recent example of the latter would be this column I wrote for the
New York Times
about keeping berries and fruits longer than normal. I had been going to the farmers’ market and getting way too much fruit. It looked and tasted so good, but I couldn’t eat it all, and after a day, it would begin to mold, sometimes even in the refrigerator. I thought there might be a way to deal with this. So I drove up to UC Davis and used their online databases to search the literature for methods of controlling mold growth on produce.

I discovered that back in the 1970s some guys at one of the ARS [USDA Agricultural Research Service] stations here in California came up with a mild heat treatment that didn’t damage the fruit but did slow down substantially the growth of mold on the outside. I came back and gave it a try, and it worked. I didn’t have the knowledge or the tools to deal with it without doing some library research. I put it to the test because it’s one thing to read about something in the literature and another thing to make sure that it actually plays out that way in somebody’s kitchen.

Why not do this kind of literature search online? Is there something that UC Davis or an institution like that is able to provide researchers that they can’t get directly online back home in front of their computers?

There are wonderful resources that are available at both university and public libraries that an individual just can’t afford to subscribe to. In institutions with a food science department, there are resources on the shelf that you would never know about without going and looking, and I enjoy doing that, not necessarily to answer the question “What do people know today about X?” but more “How have people dealt with X over the centuries?”

Centuries? Can you give me an example of something from that kind of historical research?

Tomato leaves are not toxic the way people thought they were. In fact, they’re probably beneficial to eat because they bind to cholesterol and prevent us from absorbing it. The question arose: “How did we get this idea that they’re toxic if they’re not?”

I delved back as far as I could in some pretty obscure literature to try to figure that out, and that included going up to UC Davis and taking a look at a couple of books from the 17th and 18th centuries on Dutch ethnography of the Pacific. I tracked down a reference to people eating tomato leaves on an island in the Indonesian Archipelago in the 17th century. This would have been shortly after tomatoes had been introduced there because they are not native to that part of the world. That fleshes out the story of how this plant found its way around the world, how it developed a reputation, and the kinds of aesthetic judgments that people made about it.

In Europe, people didn’t eat the leaves because they thought they stank. In Central and South America, where tomatoes came from, the leaves weren’t much eaten, which I still don’t understand. Just pulling all of these bits together to me is part of the pleasure of understanding and appreciating the food that I sit down and eat at my table today. There is this tremendous depth of history and complexity that, if you delve into it, can make it even more pleasurable to eat these things.

One of the things I like best about the job I have is not so much the writing; it’s the exploring, it’s tracking down these books and reading this paragraph about people on this island centuries ago doing this with the leaves, then coming home and trying to get some sense of what that tasted like using leaves from my own backyard and the equivalent of the preserved fish that they were probably using back then to season them.

I imagine that our understanding about food is getting more refined, and we’re correcting a lot of previous misconceptions. What do you hope future research will spend time working on?

If I could name one area that I wish people with the equipment, expertise, and resources would pay more attention to and work harder on, it is flavor and the influence of different cooking methods on the ultimate experience of particular preparations. There are so many interesting questions about different ways of doing the same thing where, at the moment, basically you have your own personal experience and the experience of other people but no good, objective yardstick.

What are the real differences? Are we experiencing the same set of compounds differently because we have different sensory systems, or do, in fact, different techniques produce different sets of compounds where you happen to prefer this and I happen to prefer that? An example would be making stocks. There are some people who are real partisans of doing stocks in pressure cookers and others who think that the long, slow, barely-at-a-simmer method gives you a superior result. I’ve done both, and I like both, but they are different. I’m not sure I can really explain how they are different, so I would love to know what’s going on there.

What does the home cook need to understand about what they’re doing in the kitchen?

A scale and a good thermometer are absolutely essential if you’re going to try to understand things and do experiments carefully enough to draw real conclusions. You need to be able to measure, and temperature and weight are the main variables.

Is there something that really surprised you in the kitchen?

I suppose the one moment in my life that really confounded my expectation was the copper bowl versus glass bowl for beating egg whites. I was reading Julia Child while I was writing the book [
On Food and Cooking
] the first time in the late 1970s. She said that you should whip egg whites in a copper bowl because it acidifies the whites and gives you a better foam for meringue and soufflés, but the chemistry was wrong. Copper doesn’t change the pH of solutions, so I thought that since the explanation was wrong, there probably was nothing to the claim either.

Then a couple of years later, when it came time to get ready for publication, I was looking at old graphic sources for illustrations for the book. I looked at a French encyclopedia from the 17th century that had a lot of professions illustrated. One of them was a pastry kitchen. In the engraving, there was a boy beating egg whites, and it said that the boy was beating egg whites in a copper bowl to make biscuits. It specified a copper bowl, and it looked exactly like today’s copper bowls: it was hemispherical and had a ring for hanging. I thought if a French book from 200 years ago is saying the same thing that Julia Child said, then maybe I should give it a try.

I tried a glass bowl and a copper bowl side by side, so I could look at them and taste them, and the difference was huge. It took twice as long to make a foam in the copper bowl; the color was different, the texture was different, the stability was different. That was a very important moment for me. You may know that somebody else doesn’t know the chemistry, but they probably know a lot more about cooking than you do. That certainly got me to realize that I really did have to check everything I could.

A French chef told me a story. He’d made a million meringues in his life, and one day he was in the middle of whipping the egg whites in a machine. The phone rang — there was some kind of emergency and he had to go away for 15 or 20 minutes — so he just left the machine running. He came back to the best whipped egg whites he’d ever seen in his life. His conclusion from that was, in French, “
Je sais, je sais que je sais jamais
.” It sounds a lot better in French than it does in English, but the English is, “I know, I know that I never know.”

Thanks to that experience with the copper bowl, that’s been my motto as well. No matter how crazy an idea sounds or how much I distrust my own senses when I do something, and it somehow seems inexplicably different from what it should be, I know that I’m never going to understand everything completely, and there’s probably a lot more to learn about whatever it is that’s going on.