21 Things That Might Surprise You in Harold McGee’s “On Food and Cooking”


By: Gerry Kagan
You must get this book...

You must get this book... 

Harold McGee’s “On Food and Cooking” can be an unsettling experience. Browsers of this vast book constantly encounter utterly familiar foods and techniques, things like water, boiling water, potatoes, salt, bread, and come away with the impression that this familiarity was almost a kind of mirage. McGee reveals startlingly new and strange aspects of the commonplace on what seems like every page.

Water, it turns out, is not the neutral, passive liquid of everyday experience but an extremely active and even bizarre substance. Salt, in its numbingly familiar form as “table salt”, is a uniquely dynamic and transformative material, almost magical in its power to make other things into food. Bread doesn’t go stale because it “dries out”, but because of changes in the chemistry of its starch that are not related to moisture. McGee almost always goes beneath the surface of the familiar to discuss the chemical realities that underlie the things we know by our senses. To some people, this may, at first hearing, sound dull or reductive, but McGee’s method consistently expands a sense of wonder of the physical world and heightens our engagement with it.

McGee discusses virtually everything: cardamom, fish sauce, moonshine and Hubbard squash. He explains how every method of cooking and food preparation actually works and how the energy and molecules in cooking interact with our experience of taste and eating. This approach is anything but abstract and McGee offers countless suggestions and nifty techniques for making foods more delicious and pleasurable. Here, almost randomly, are twenty-one things you could learn that might surprise you by spending some time with Harold McGee’s completely revised and updated 2004 edition of “On Food and Cooking: the Science and Lore of the Kitchen”;

1) Most fish are not best eaten immediately after being killed but 8 to 24 hours later, after rigor mortis (the “stiffness of death”) has occurred and then passed, relaxing the contraction of the fish’s muscle cells and allowing the cellular energy carrying compound ATP to break down into an “umami” –rich, savory compound abbreviated as IMP.

2) Meat from the tail of a fish, the part that does most of the work of swimming, contains more gelatin and fat than the lazy meat around the head and is generally moister and more succulent as a result.

3) Brazil nuts cannot be harvested from the 150 foot tall trees that bear them. The 5 lb nut pods must fall from the tree on their own and gatherers must work with shields to avoid being killed by them. Brazil nuts contain more selenium than any other food, and the World Health Organization recommends a daily maximum intake of just one half an ounce of Brazil nuts to avoid ingesting a toxic overdose of this element.

4) Cashews are related to poison ivy and their shells are dangerous. Many people in cashew country (India and East Africa) don’t even bother with the cashew nuts we value so highly, discarding them in favor of the swollen stem of the plant’s fruit, the “cashew apple”, which is eaten fresh, cooked or fermented into an alcoholic drink.

5) Pre-cooking potatoes, carrots, beets, apples, and other dense fruits and vegetables at a low temperature for a certain amount of time can activate an enzyme in their cell walls that causes them to remain firm. They can then be fully cooked for an extended period without becoming soft or mushy, even on their surface.

6) The thickening of tomato puree is not a simple matter of cooking out the water; it matters at what temperature the puree is cooked and how fast it is heated. When tomato puree is heated quickly to just below the boiling point, an enzyme that breaks down cell walls and liberates water is de-activated and, weirdly, less cooking results in a thicker sauce than longer cooking may produce.

7) Tomatoes are complicated. The fresh tomato flavor that is lost through cooking can be restored to a sauce with the addition of tomato leaves near the end of the process. These leaves are rich in “green” flavor enzymes and aromatic oils, and they are not toxic to people. The potentially poisonous substance in tomato leaves, tomatine, binds to cholesterol in our digestive tract and is not metabolized.

8) The flavorings in most herbs and spices including oregano, vanilla and peppercorns, are chemical weapons designed to deter nibbling by animals and microbial invaders.

9) Marshmallows are called that because the original confection they resemble was made from the gummy juice of a flower, a “marsh mallow” found in the swamps of France.

10) Searing meat to “seal in the juices” is a complete myth from the 19th century that was disproven decades ago but lives on as an endlessly repeated factoid. But searing does create flavor in meat with the formation of myriad chemical products of the browning reaction, including pyradines, pyrazines and ozazoles, the sources of chocolatey, earthy and floral flavors.

11) The reason a lobster must be kept alive until very shortly before being cooked is that, immediately after death, its digestive enzymes break down the cells containing them and spread to the muscle flesh of the lobster, turning it to mush. The lobster virtually digests itself.

12) Shrimp shells actually add flavor to the flesh of the shrimp during cooking.

13) The foundation of ancient Roman cooking was a fish sauce made from the guts of mackerel. The innards were salted, left in the sun for several months to putrefy until the flesh fell apart, and then strained to draw off a brown liquid called garum. [Can a Brooklyn-based garum revival be far off?]

14) The quality of wild fish can vary from season to season more drastically than that of land animals because most fish cannot store energy in fat reserves like beef or pigs. During migration and spawning cycles, fish generally exhaust the proteins in their muscles to obtain the energy needed to produce the next generation of fish, often resulting in spongy, disappointing steaks or fillets.

15) Traditional pumpernickel bread is baked at a low temperature for 16 to 24 hours. The long cooking time and low heat allow starch-digesting enzymes to convert much of the dough to sugar, sometimes accounting for 20% of the finished loaf’s weight.

16) In the Middle Ages, bakers of common, brown bread formed their own guild, separate from bakers who made white bread for the well-to-do. One use of coarse, heavy non-wheat bread was the “trencher”, a dry, thick flatbread that served as a plate for Medieval meals and was then often given to the poor.

17) Medlars are an obscure relative of apples that were popular in Medieval times but are now quite rare. Like quince, medlars are inedible raw even when ripe. They are eaten after several weeks in storage, after they have been digested from within by their own enzymes, in a state of rottenness, really.

18) As to the staling of bread, the gradual hardening of the starch in bread that occurs even without any loss in moisture can be reversed by re-heating it to 140 degrees F. Toasting doesn’t just mask the staleness of bread, it undoes it chemically, which is why the interior of a piece of toast is soft.

19) Salt and sugar don’t merely add saltiness and sweetness to food, they enhance and intensify our perception of the aromas of the foods they season.

20) When a molecule of salt dissolves, it immediately separates into separate sodium and chloride atoms. These ions are smaller and more mobile than anything else we add to meat or vegetables. They penetrate foods and alter the chemistry of food in a unique way, disrupting spoilage bacteria, allowing the growth of beneficial bacteria, pulling water into foods where we want it, drawing water out of foods when that is desirable.

21) Lastly, water, by far the largest component of our foods, is constantly forming electrical bonds with almost everything it touches, including itself. Water molecules are structured so that one end, the oxygen side, readily latches onto positively charged ions, and the hydrogen side bonds with negatively charged ions that it comes in contact with. That means that water molecules are constantly forming bonds with each other, even in a liquid state. One result of this is that a pot of water doesn’t immediately start to warm up when it is heated on the stove. Almost all of the initial energy absorbed by the water must first be used to break these weak electrical bonds between the water molecules. Water takes twice as long to heat up as the same amount of vegetable oil. And, of course, it retains heat that much longer than other liquids.

Harold McGee is more than an authority on food and cooking with an unusual grasp of chemistry, he is a consummate humanist. His steady focus is to understand our experience as human beings and to expand the quality and emotional richness of the fundamental acts of preparing and eating food. His presence in your kitchen and at your table is something to celebrate.

You must get this book… Available cheap at Amazon

1 comment
  1. Katia Troosh

    Harold McGee is an endlessly interesting and knowledgeable man, very soft spoken and low key. He came to a meeting of our club, “The Baker’s Dozen”, in San Francisco. He gave a very interesting and informative talk and spent a long time answering many questions. The members thoroughly enjoyed his visit.

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