What Einstein Told His Cook (10 page)

I got out my calculator. Now, let’s see. One gram of saturated fat plus zero grams of polyunsaturated fat plus two grams of monounsaturated fat makes three grams of total fat, not six. What happened to the other three grams?

Next, I grabbed a box of Premium Original Saltine Crackers. Worse yet! The two grams of total fat are supposedly made up of zero grams of saturated fat, zero grams of polyunsaturated fat, and zero grams of monounsaturated fat. Since when does zero plus zero plus zero equal two? I didn’t even need my calculator to know that something was wrong with that one. Something very strange was going on here. I hurried to my computer and pulled up the Web site of the FDA, the agency that made the rules for the nutrition labeling of prepared foods. The FDA’s site has a page that answers frequently asked questions about food labeling. Here’s what I found.

“Question: Should the sum of saturated, monounsaturated, and polyunsaturated fatty acids equal the total fat content?

“Answer: No. The sum of the fatty acids generally will be lower than the weight of total fat, because the weights of components of fat such as trans fatty acids and glycerol are not included.”

Aha! So that’s it!

Still not clear? Lemme ’splain it to ya.

A fat molecule consists of two parts, a glycerol part and a fatty acid part. Although the number of grams of “Total Fat” on the label is indeed the weight of the whole fat molecules, glycerol parts and all, the amounts of “Saturated Fat,” “Polyunsaturated Fat,” and “Monounsaturated Fat” are the weights of the fatty acid parts alone. Part of the missing weight is the combined weights of the glycerol parts of all the fat molecules. (I’ll get to the trans fatty acids later.)

Why, then, are these amounts called “fats” on the labels instead of what they really are: fatty acids? According to Virginia Wilkening, deputy director of the FDA’s Office of Nutritional Products, Labeling and Dietary Supplements, there are two reasons: (1) the general public wants to know only the relative amounts of saturated and unsaturated stuff in their fats, and it’s the fatty acid parts alone that determine that; (2) space is at a premium on food labels, and the words “fatty acids” take up more space than “fats.”

Okay, I guess, but the inaccurate wording still annoys nitpickers like me.

As the FDA’s Q&A page admits, there is even more fudging in the Nutrition Facts panel, because the weights of the trans fatty acids are not included in the list. In fact, they usually account for even more of the missing weight than the glycerols do.

Trans fatty acids are the latest villains to appear in the Frightening Fat Follies; they seem to raise the levels of LDL (“bad”) cholesterol in the blood just about as much as naturally saturated fatty acids do. Trans fatty acids don’t occur naturally in vegetable oils, but are formed when they are hydrogenated. The two added hydrogen atoms may attach themselves to opposite sides of the carbon chain (Techspeak: in the trans configuration) instead of both on the same side (Techspeak: in the cis [pronounced
sis
] configuration). That changes the molecular shape of the fatty acid from kinked to straight, thus making them resemble and behave like saturated fatty acids.

Partially hydrogenated vegetable oils may contain substantial amounts of trans fatty acids but, largely because of difficulties in determining their amounts, they are not currently reported separately on food labels.

In your own pursuit of longevity, you will still want to pay attention to the amount of “Total Fat” listed on the label. But to learn whether it is primarily “good fat” or “bad fat,” disregard the exact numbers of grams and pay attention to the
relative
amounts of saturated, polyunsaturated, and monounsaturated fat(ty acids). That’s what counts. And remember that at this writing the villainous trans fatty acids are still lurking somewhere off the label. The FDA is considering listing them together with the saturated fatty acids.

Oh, and what about those “zero grams of fat(ty acids)” in my Premium Crackers that mysteriously add up to 2 grams of total fat? Are there some kinds of fat that have no fatty acids attached to them at all? No. Then they wouldn’t be fats. It’s that the FDA permits manufacturers to list “zero grams” of either a fat or a fatty acid when the amount is less than 0.5 gram per serving.

The rules of arithmetic that we learned in first grade are not in jeopardy.

IS THAT PERFECTLY CLEAR?

I have a recipe that calls for clarified butter. How do I do that? And what does clarifying butter accomplish besides, well, making clear butter?

T
hat depends on your point of view. Clarifying butter gets rid of everything but that delicious, artery-clogging, highly saturated butterfat. But when we use it in sautéing instead of whole butter, we avoid eating the browned proteins, which could also be unhealthful because of possible carcinogens. Name your poison.

Some people think of butter as a block of fat surrounded by guilt. But guilt or no guilt, it isn’t all fat. It’s a three-part mixture of fat, water, and protein solids. When we clarify butter, we’re separating out the fat and throwing everything else away. Using the pure fat, we can sauté at a higher temperature without any burning or smoking, because the water in whole butter holds the temperature down and the solids do indeed tend to burn and smoke.

When heated in a frying pan, the solid proteins in whole butter begin to turn brown and smoke at around 250ºF. One way to minimize these goings-on is to “protect” the butter in the pan with a little cooking oil, which might have a smoking temperature of around 425ºF. But you’ll still get a little browning of the proteins in the butter.

Or, you can use clarified butter. It’s the pure oil without the proteins, and it won’t set off your smoke alarm until about 350ºF.

Clarified butter will keep much longer than whole butter will, because bacteria can work away at protein, but not at pure oil. In India, where refrigeration can be scarce, they make clarified butter (
usli ghee
) by melting it slowly and then continuing to boil off the water, whereupon its proteins and sugars become slightly burned, producing a pleasant, nutty flavor.

Eventually, clarified butter will turn rancid. But rancidity is only a sour flavor, not bacterial contamination. Tibetans, in fact, prefer their clarified yak butter on the rancid side.
Chacun à son goût
.

BETTER BUTTER

In France, I had the most marvelously flavorful butter—better than anything I’ve had in the States. What makes it so different?

M
ore fat.

Commercial butter is 80 to 82 percent milk fat (also called butterfat), 16 to 17 percent water, and 1 to 2 percent milk solids (plus about 2 percent salt if salted). The United States Department of Agriculture (USDA) sets the lower limit of butterfat content for American butter at 80 percent, while most European butters contain a minimum of 82 or even as much as 84 percent.

That may not sound like much of a difference, but more fat means less water and hence a richer, creamier product. Pastry chefs often refer to European butter as “dry butter.” Moreover, higher-fat butter makes smoother sauces and flakier and more flavorful pastries. (Compare the croissants you had in France with those
anything-that’s-bent-in-the-middle
American imitations.)

Butter, as you know, is made by churning cream or whole, unhomogenized milk. The agitation of churning breaks up the emulsion (tiny globules of fat suspended in water) in the cream, so that the fat globules are free to coalesce into granules the size of rice grains. These then mat together and separate from the watery part of the milk, called the buttermilk. (Today’s cultured buttermilk products have been processed further.) The fat is then washed with water and “worked” to squeeze out more buttermilk. European butter is generally made in small batches, allowing for more complete removal of the buttermilk.

Some American brands of European-style butter are Keller’s, formerly known as Plugrá, a pun on the French
plus gras
, meaning “more fat” Land O’ Lakes Ultra Creamy; and Challenge. European butters imported from France and Denmark are available in specialty stores. Bring lots of
euros
.

THE BIG SQUEEZE

I think of corn as a low-fat food. So how do they get all that corn oil out of it?

T
hey use a lot of corn.

Corn is indeed a low-fat food—containing about 1 gram per ear until you slather it with all that butter. But it is by far the biggest crop in the United States, grown in 42 states to the tune of more than 9 billion bushels per year. Nine billion bushels of corn contain some 3 billion gallons of oil, and that’s enough to deep-fry Delaware.

The oil resides in the germ of the grain, where Mother Nature stores it as a concentrated form of energy—9 calories per gram—to fuel the everyday miracle of creating whole new plants from seeds. In corn, the germ makes up only about 8 percent of the kernel and only about half of that is oil, so an ear of corn isn’t exactly a gusher.

As you can imagine, it takes some doing to get the oil out. At the mill, the kernels are steeped in hot water for a day or two, then coarsely ground to break the germ loose. The germ is then separated by a floating or spinning process, after which it is dried and crushed to press out the oil.

UP IN SMOKE

How do the various cooking oils differ in their boiling points, and what are the consequences for the cook?

I
don’t think you mean boiling point, because in spite of the poetic and sadistic appeal of the expression “boiled in oil,” oil doesn’t boil.

Long before it becomes hot enough to think about bubbling, a cooking oil will decompose, breaking down into disagreeable chemicals and carbonized particles that will assault your taste buds with a burnt flavor, your nostrils with an acrid smell, and your ears with a shrieking smoke alarm. If you mean the highest practical cooking temperature for an oil, it is limited not by a boiling point but by the temperature at which the oil begins to smoke.