What Einstein Told His Cook (35 page)

To nail this down, I tested the opposite effect: I poured a leveled metal measuring cup of sugar into a tall, narrow measuring vessel—a chemist’s graduated cylinder. As I expected, it filled the cylinder quite a bit higher than the eight-ounce (237-milliliter) mark.

Modern glass measuring utensils are, unfortunately, even wider than their predecessors, probably because people today want to heat milk or other liquids in them in their microwave ovens, and those liquids won’t froth or boil over as easily in a wide container. So today’s liquid measurers are particularly poor for measuring dry ingredients. But there’s a problem even when measuring liquids in them. In a wide container, a small error in the filling height can make a relatively large error in the volume. Those big, widemouthed glass measurers are therefore not as precise in use as the older, narrower ones. If you still have one of the oldies, cherish it.

And then there’s the problem of measuring out teaspoons and tablespoons of liquids. Have you noticed how surface tension makes the liquid bulge up above the rim of the measuring spoon? How accurate can that possibly be? Those spoons were made for solids, not liquids.

The perfect solution to all these problems, I’ve found, is the aptly named Perfect Beaker, made by EMSA Design of Frieling USA. It’s calibrated in every kind of liquid measurement you could want: ounces, milliliters, teaspoons, tablespoons, cups, and pints, including fractions thereof. This single measuring device is all you need, from one ounce to one pint. Its ice-cream-cone shape ensures that smaller amounts of material are automatically measured in a narrower container, producing the highest accuracy in reading. You can also use it to convert from one unit to another, which will come in handy at the beginning of the next millennium when, judging by progress thus far, the U.S. will finally be coming around to using the Metric System. Just find your American amount on the scale and read its metric equivalent at the same level.

The Perfect Beaker. Its conical shape provides maximum accuracy for small amounts of liquids.

(Or am I being too pessimistic? After all, it’s been only twenty-seven years since Congress passed a law requiring metric conversion, and already Coke and Pepsi come in two-liter bottles.)

The ultimate answer to accuracy and reproducibility in the kitchen is quite simple, but except for professional bakers and other chefs, we Americans just won’t do it: Instead of measuring solid ingredients by volume, such as by tablespoons and cups, weigh them; that’s what most cooks in the rest of the world do. In metric units, for example, one hundred grams of sugar is always the same amount of sugar, no matter whether it’s granulated or powdered or what kind of container you put it in. For liquids, there’s only one metric unit: the milliliter or its multiple, the liter (one thousand milliliters). No cups, pints, quarts, or gallons to fuss with.

Quick: How many cups in half a gallon?

See what I mean?

A LONG INSTANT

Why is my “instant-read” thermometer so slow to tell me the food’s temperature?

T
here are two types of so-called instant-read thermometers: the dial-type and the digital readout type. But do they really give you the temperature reading in an instant? Don’t you wish! These reputed speed demons can take anywhere from 10 to 30 seconds to climb up to their highest readings, which are, of course, the numbers you need to see. Withdraw one from the food before it has reached that maximum reading and you’ll be underestimating the temperature.

Certainly, you’re in a hurry to get the reading. You don’t want to stand there with your hand in the oven until a dawdling thermometer decides to reveal your roast’s actual internal temperature. But the sad truth is that no thermometer can register the temperature of a food until it itself—the thermometer, or at least its probe—has reached the temperature of the food into which it has been thrust. In fact, you might say that the only thing a thermometer can do is tell you its
own
temperature. There is little you can do about the time it takes for the thermometer to heat up to the temperature of the food, except to choose a digital, rather than a dial, thermometer because, as I’ll explain below, digitals generally read faster than dials.

What you
can
do something about is knowing exactly where in the food you are measuring the temperature. The two types of “instant reading” thermometers differ substantially in this respect.

Dial types sense the temperature by means of a bimetallic coil in the stem: a coil made of two different metals bonded together. Because the two metals expand at different rates when heated, heat makes the coil twist, which in turn twists a pointer on a dial. Unfortunately, the temperature-sensing coil is usually more than an inch long, so you’re actually measuring the temperature averaged over a substantial region of the food. But you often need to be able to measure a highly localized temperature. Inside a roasting turkey, for example, the temperature varies quite a bit from place to place, but to test for doneness you need to know the specific temperature in the thickest part of the thigh.

A digital thermometer, on the other hand, measures the temperature at a more precise spot in the food. It contains a tiny, battery-operated semiconductor whose electrical resistance varies with temperature. (Techspeak: a thermistor.) A computer chip converts the resistance into electrical signals that operate the numerical display. Because the tiny thermistor is down in the tip of the probe, a digital thermometer is especially good for monitoring a grilled steak or chop, for example, where you need to know the temperature in dead center.

A digital thermometer manufactured by Component Design.

The other advantage of the digitals is that because their thermistors are so small, they acquire the food’s temperature quickly. That’s why they usually give you a faster reading than the dial types.

NOW WE’RE COOKING

COOKING UNDER PRESSURE

My mother’s diabolical pressure cooker from the 1950s seems to be coming back in modern dress. Exactly what do they do?

T
hey speed up cooking by making water boil at a higher-than-normal temperature.

In the process, they may hiss, rattle, and sizzle like an infernal machine, threatening to redecorate your kitchen in shades of goulash. But your mother’s pressure cooker has been re-engineered to be more mannerly and nearly foolproof. As with all cooking appliances, though, safety is a matter of understanding. Unfortunately, the instructions that come with the pressure cookers are full of scary dos and don’ts that make no sense unless you understand how the things work. That’s what I’m here for.

Pressure cookers burst—pardon me, appeared—upon the scene after World War II as the “modern” way to cook for homemakers whose time was overprogrammed with cooking, cleaning and kids. Today, those baby-boom kids have grown up and are themselves overprogrammed with jobs, gyms, and Jeeps. Any gadget that promises a gold medal for speed in the Kitchen Olympics is a sure sell.

No matter how many shortcuts you take, though, there are two unavoidable, time-consuming steps in all cooking. One is heat transmission—getting the heat into the interior of the food. That can be the bottleneck in many a “quick” recipe, because most foods are poor conductors of heat. The other slow step is the cooking reactions themselves. The chemical reactions that change our foods from raw to cooked can be quite slow.

Microwave ovens circumvent the slowness of heat conduction by generating the heat right inside the food itself. But many dishes such as soups and stews benefit from the slow marrying of flavors that takes place in water-based cooking methods such as braising: the searing and simmering of meats and vegetables in a small amount of liquid in a covered vessel. You can’t do that in a microwave oven because the microwaves, not the simmering liquid, will do the cooking.

To speed up braising, we would like to use a higher temperature, because all chemical reactions, including those in cooking, go faster at higher temperatures. But there is a big obstacle: Water has a built-in temperature limit of 212°F, its boiling point at sea level. Turn up the heat to flame-thrower intensities and the water or sauce will certainly boil faster, but it won’t get one bit hotter.