On Food and Cooking: The Science and Lore of the Kitchen

Harold McGee

Scribner, 896 pp., $40

I first learned to cook at my grandmother’s knee (well, shoulder–she was pretty short), nagging for a chance to roll out the dough, turn the meat grinder’s crank, or fill the blintz. It was the school of intuitive cooking, a compound of vague measurements and unarticulated moves.

Later, out on my own, I became a book-driven, obsessive recipe follower, painstakingly working my way through Julia 1 (aka Mastering the Art of French Cooking, Vol 1) and Albert Stockli’s Splendid Fare, among others. I was now attending the school of teaspoons and grams.

And then it slowly dawned on me. There was only one school, but it had two different entrances. And there was something both syllabi left out–the underlying mechanisms of cooking that explain why anything you do in the kitchen works at all. Or, when it fails, why it fails. I wanted the Advanced Polytechnic for Cooking Nerds.

I don’t mean explanations like: The bread sucks because you left out the salt. I mean explanations like: The texture sucks because you left out the salt and “salt tightens the gluten network … and helps limit the protein digesting activity of the souring bacteria, which can otherwise damage the gluten.”

If your eyes have already started to glaze over and if you don’t want to know why fish spoils faster than meat, why duck breasts are red and chicken breasts are white, what buttermilk once was (and is no longer), why raw milk cheeses are safer than factory cheeses, why egg whites and steamed milk make stable foams and why walnuts can turn blue, then you can stop reading now because you don’t want to know about Harold McGee’s long-awaited, 20 years in the re-making, revised On Food and Cooking: The Science and Lore of the Kitchen (a book, at 800+ pages, that is even longer than this sentence).

There are many ways in which this book isn’t a mere collection of facts about this food or that. One way is the obvious one, in that many cooking properties are determined by fairly generic facts about proteins, carbohydrates, fats, salt and water.

Despite its molecular orientation, there’s also a lot of food history and detailed paeans to basic ingredients in On Food and Cooking. The paeans are, sadly, often eulogies. The ancestral milk and honey (and cheeses and hams and fruits) are largely gone, replaced by pallid pretenders. It turns out that while the big picture is about protein and carbohydrates and fat, the flavor devil is in the details of those thousands of small, parts per billion, aromatic molecules suppressed by the technology of factory food.

Still, what this book is is learned fun. You won’t read it cover to cover but in prolonged chewy nibbles. Long as it is, it is a well written, beautifully organized presentation of the underlying biochemistry and physics of food and cooking. Much of the text concerns the interactions of proteins, carbohydrates, fats and water under the influence of heat, agitation, freezing and other abuse, but not a paragraph goes by that doesn’t connect to an actual cooking or eating experience. There is also quite a bit on foods’ interaction with humans and a bit on how, evolutionarily speaking, foods–and we–got to be that way in the first place.

One of the many pleasures of the book is how palpably McGee renders the connection between theory and practice. Readers will learn to intelligently modify recipes or substitute for that missing or loathsome ingredient.

In the custard section he starts with the general: ” …custards are almost always made with milk or cream, but just about any liquid will do as long as it contains some dissolved minerals.” Then he illustrates the point: “Mix an egg with a cup of plain water and you get curdled egg floating in water; include a pinch of salt and you get a coherent gel.” Then back to the theory: “Without minerals, the negatively charged, mutually repelling protein molecules avoid each other as they unfold in the heat … With minerals, positively charged ions cluster around the negatively charged proteins … which makes it possible for the proteins to unfold near each and bond … into a fine network.”

Meat gets a nice long treatment: prehistory, history, and, of course, the science of muscle fibers, connective tissue and fat. (But, then, everything gets a nice long treatment. See the table of contents in the sidebar.) I had always known the vague version of why some cuts are tough and some are tender–something about exercise. McGee gives us the details and how those details affect cooking methods. And we learn why (and how) duck breast is red and chicken breast is white.

Of course, these are not isolated facts; duck breasts are red for the same reason and in the same way that pheasant leg muscles and beef steaks are red and why whale muscle is nearly black.

Accounts like those are about sameness; but what about difference?–beef and lamb are different flavors. It turns out that generic meatiness comes from the muscle fibers, whereas idiosyncratic flavors arrive via fat. Meaty flavor arises from the breakdown of muscle fiber effected by enzymes and heat. These “amino acids, short chains of them, sugars, fatty acids, fragments of DNA and RNA, and salts–are what stimulate the tongue with sweet, sour, salty and savory sensations. And … they react with each other to form hundreds of aromatic compounds.” Red fibers, and well-exercised fibers, contain more of the material for generating these flavor substances.

This is one reason that modern meat production methods that immobilize animals and breed them for fast growth produce flavor-challenged products.

The temptation is to go on excerpting random facts from this book’s almost 900 pages, but I’ll content myself with mentioning my favorite myth-puncturing fact. Cookbooks ask you to sear meat (either for the grill or in preparing a stew) to seal in the juices. A moment’s thought or observation should have quashed this rationale for searing long ago. It is obviously ineffective–wrapping the pieces tightly in aluminum foil would do a much better job. And certainly in the case of stews you don’t want to isolate the juices.

Searing isn’t sealing but it is nonetheless a good thing. It makes flavor via the Maillard reaction, the browning process that is implicated in bread crusts, coffee beans and dark beers. The Maillard reaction produces the flavor compounds that make those things worth eating.

After reading all about the inner workings of meats, vegetables, fruits, herbs, fishes and sauces, and about the complex effects of cooking on our food, there’s one big mystery left hovering. How did my grandmother figure all this out?