Robert L. Wolke

What Einstein Told His Cook

An excerpt

Fasta Pasta

Why do we have to put salt in the water before boiling pasta in it? Does it make the pasta cook faster?

....
Virtually every cookbook instructs us to salt the water in which we cook pasta or potatoes, and we dutifully comply without asking any questions.

There is a very simple reason for adding the salt: It boosts the flavor of the food, just as it does when used in any other kind of cooking. And that's all there is to it.

At this point, every reader who has ever paid the slightest attention in chemistry class will object. "But adding salt to the water raises its boiling point, so the water will boil hotter and cook the food faster."

To these readers I award an A in chemistry but a D in Food 101. It's true that dissolving salt—or really anything else, for that matter (I'll explain)—in water will indeed make it boil at a higher temperature than 212°F at sea level. But in cooking, the rise is nowhere near enough to make any difference, unless you throw in so much salt that you could use the water to melt ice on your driveway.

As any chemist will be happy to calculate for you, adding a tablespoon (20 grams) of table salt to five quarts of boiling water for cooking a pound of pasta will raise the boiling point by seven hundredths of 1ºF. That might shorten the cooking time by half a second or so. Anyone who is in that much of a hurry to get the spaghetti onto the table may also want to consider rollerblading it from the kitchen to the dining room.

Of course, you know that as an incorrigible professor I now feel obliged to tell you why salt raises the boiling point of water, small as the effect may be. Give me one paragraph.

In order to boil off, that is, in order to become vapor or steam, water molecules must escape from the ties that bind them to their liquid fellows. Wresting themselves loose with the aid of heat is tough enough because water molecules stick together quite strongly, but if there happen to be any alien particles cluttering up the liquid, it's even tougher, because the particles of salt (Techspeak: the sodium and chloride ions) or other dissolved substances simply get in the way. The water molecules therefore require some extra oomph, in the form of a higher temperature, in order to make good their escape to airborne freedom. (For more, ask your friendly neighborhood chemist about "activity coefficients.")

Now back to the kitchen.

Unfortunately, there is even more mumbo jumbo surrounding the addition of salt to cooking water than the fallacy about boiling temperature. The most frequently cited fables, even in the most respected cookbooks, tell us precisely when we must add the salt to the water.

One recent pasta cookbook observes that "it is customary to add salt to the boiling water prior to adding the pasta." It goes on to warn that "adding the salt before the water boils may cause an unpleasant aftertaste." Thus, the recommended routine is (1) boil, (2) add salt, (3) add pasta.

Meanwhile, another pasta cookbook counsels us to "bring the water to the boil before adding salt or pasta," but leaves open the momentous question of salt-first or pasta-first.

The fact is that as long as the pasta cooks in salted water, it makes no difference whether or not the water had already been boiling when the salt was added. Salt dissolves quite easily in water, whether hot or merely lukewarm. And even if it didn't, the roiling of boiling would dissolve it immediately. Once dissolved, the salt has no memory of time or temperature—of precisely when it entered the water or of whether it took the plunge at 212ºF or 100ºF. It cannot, therefore, affect the pasta differently.

One theory I have heard from a chef is that when salt dissolves in water it releases heat, and that if you add the salt when the pot is already boiling the extra heat can make it boil over. Sorry, Chef, but salt doesn't release heat when it dissolves; it actually absorbs a little bit of heat. What you undoubtedly observed is that when you added the salt, the water suddenly erupted into livelier bubbling. That happened because the salt—or almost any other added solid particles—gives the budding bubbles many new places (Techspeak: nucleation sites) upon which to grow to full size.

Another theory (everybody has one, it seems; is boiling pasta such an Earth-shaking challenge?) is that the salt is added for more than flavor, that it toughens the pasta and keeps it from getting too mushy. I have heard some plausible but quite technical reasons for that, but I won't trouble you with them. Let's just add the salt whenever and for whatever reason we wish. Just make sure we add it or the pasta will taste blah.

Perchance to Enhance
What is MSG, and does it really "enhance flavors"?

.... It certainly does sound mysterious that these innocent-looking fine, white crystals with no really distinctive taste of their own should be able to boost the inherent flavors of such a wide variety of foods. The mystery lies not in whether MSG really works—nobody doubts that—but in how it works. As is the case with so many ancient, stumbled-upon practices, a lack of scientific understanding hasn't stopped people from enjoying the benefits of MSG for more than two thousand years.

What makes MSG's reputation as a flavor enhancer so hard to swallow is that the terminology is somewhat misleading. Flavor enhancers don't enhance the flavors of foods in the sense of improving them; that is, they don't necessarily make things taste better. What they seem to be doing is intensifying, or magnifying, certain flavors that are already present. The food processing industry likes to call them potentiators; I call them flavor boosters.

At this point, I'm obliged to acknowledge the debate about its effects on sensitive individuals.

Everyone has heard of Chinese Restaurant Syndrome or CRS, an unfortunate and politically incorrect label that was applied in 1968 to a diffuse collection of symptoms, including headaches and burning sensations, reported by some people after consuming their selections from column A and column B. The culprit behind CRS appeared to be MSG, which is short for its chemical name, monosodium glutamate (gluTAMate). And thus began a thirty-year battle over its safety.

In one corner sits the National Organization Mobilized to Stop Glutamate, whose uncomplicated solution to the problem is expressed in its acronym. According to NOMSG, glutamates in their many guises (see below) are responsible for at least twenty-three afflictions, from runny noses and bags under the eyes to panic attacks and partial paralysis.

In the other three corners, predictably, are the manufacturers of prepared foods, who find MSG and similar compounds to be enormously valuable in enhancing the consumer appeal of their products.

The official referee is the FDA who, after many years of evaluating data, remains convinced that "MSG and related substances are safe food ingredients for most people when eaten at customary levels." The trouble is that all people are not "most people," and the FDA is still struggling to regulate the labeling of glutamate-containing foods so as to be most useful to all consumers.

Monosodium glutamate was first isolated from kombu seaweed by a Japanese chemist in 1908. The Japanese call it aji-no-moto, which means "essence of taste" or "at the origin of flavor." Today, 200,000 tons of pure MSG is produced every year in fifteen countries. It is sold by the carload to manufacturers of prepared foods and by the ounce to consumers as Ac'cent and Zest.

Monosodium glutamate is a salt of glutamic acid, one of the most common amino acids that proteins are made of. The flavor-boosting properties reside in the glutamate part of the molecule, so any compound that releases free glutamate can perform the same trick. The monosodium version is merely the most concentrated and convenient form of glutamate.

Parmesan cheese, tomatoes, mushrooms, and seaweed are rich sources of free glutamate. That's why a little bit of any of these ingredients can give a big boost to the flavor of a dish. The Japanese have traditionally made use of seaweed's glutamate in subtle, delicate soups.

Our sense of taste involves some very complex chemical and physiological reactions. Exactly how glutamates fit in has been hard to pin down. But there are a couple of ideas that have been kicking around.

It is known that different-tasting flavor molecules stick to the receptors in our taste buds for different lengths of time before detaching. One possibility, then, is that glutamates make certain molecules stick around longer, and therefore taste stronger. Also, it is probable that glutamates have their own distinct set of taste receptors, separate from the receptors for the traditionally quoted quartet of sweet, sour, salty, and bitter. To further complicate matters, quite a few substances other than glutamates have "flavor enhancing" properties.

The Japanese long ago invented a word to describe the unique effects of seaweed's glutamates on taste: umami. Today, umami is acknowledged to represent a separate family of savory tastes that are stimulated by glutamates, similar to the family of sweet tastes that are stimulated by sugar, aspartame, and their saccharine relatives.

Many proteins contain glutamic acid, which can be broken down into free glutamate in several ways, including bacterial fermentation and our own digestion. (There are about four pounds of glutamate in the proteins of the human body.) The chemical breakdown reaction is called hydrolysis, so any time you see "hydrolyzed protein" of any kind—vegetable, soy, or yeast—on a food label, it probably contains free glutamate. Hydrolyzed proteins are the most widely used flavor boosters in prepared foods.

While a food product may not contain MSG as such and may even say "No MSG" on the label, it may well contain other glutamates. So if you suspect that you are one of the small number of people who are hypersensitive to glutamates, watch also for these euphemisms on the labels of soups, vegetables, and snacks: hydrolyzed vegetable protein, autolyzed yeast protein, yeast extract, yeast nutrient, and natural flavor or flavoring.

What's a "natural flavor," you ask? It's a substance derived from something in Nature, rather than made from scratch in a laboratory or factory. To be called "natural," it doesn't matter how chemically complex or convoluted the processes may be that ultimately isolated the flavor substance, as long as those processes began with something untouched by human hands.

As The U.S. Code of Federal Regulations 101.22(a)(3) puts it: "The term natural flavor or natural flavoring means the essential oil, oleoresin, essence or extractive, protein hydrolysate, distillate, or any product of roasting, heating or enzymolysis, which contains the flavoring constituents derived from a spice, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb, bark, bud, root, leaf or similar plant material, meat, seafood, poultry, eggs, dairy products, or fermentation products thereof, whose significant function in food is flavoring rather than nutritional. Natural flavors include the natural essence or extractives obtained from plants listed in Secs. 182.10, 182.20, 182.40, and 182.50 and part 184 of this chapter, and the substances listed in Sec. 172.510 of this chapter."

Got that?

Wine, or Wine Not? When I cook with wine or beer, does all the alcohol burn off, or does some remain, which could be a problem for a strict teetotaler, such as a recovering alcoholic?

.... Does the vino lose its power in the Crock-Pot overnight?
In a flambé baked Alaska, does the brandy lose its bite?
Does the alcohol all burn off, as the cookbooks say it does?
Or can you eat a plate of coq au vin and get a little buzz?
Well, when you cook with wine or cook with brandy, here's the scoop:
There will always be some alcohol remaining in the soup.

Many cookbooks assert that all or virtually all of the alcohol "burns off" during cooking (what they mean is that it evaporates; it won't burn unless you light it). The standard "explanation," when there is one, is that alcohol boils at 173°F, while water doesn't boil until 212°F, and therefore the alcohol will boil off before the water does.

Well, that's just not the way it works.

It's true that pure alcohol boils at 173ºF and pure water boils at 212ºF. But that doesn't mean that they behave independently when mixed; each affects the boiling temperature of the other. A mixture of alcohol and water will boil at a temperature that's somewhere between 173 and 212 degrees—closer to 212 if it's mostly water, closer to 173 if it's mostly alcohol, which I certainly hope is not the case in your cooking.

When a mixture of water and alcohol simmers or boils, the vapors are a mixture of water vapor and alcohol vapor; they evaporate together. But because alcohol evaporates more readily than water, the proportion of alcohol in the vapors is somewhat higher than it was in the liquid. The vapors are still very far from pure alcohol, however, and as they waft away from the pan, they're not carrying off very much of the alcohol. The alcohol-loss process is much less efficient than people think.

Exactly how much alcohol will remain in your pan depends on so many factors that a general answer for all recipes is impossible. But the results of some tests may surprise you.

In 1992 a group of nutritionists at the University of Idaho, Washington State University, and the USDA measured the amounts of alcohol before and after cooking two Burgundy-laden dishes similar to boeuf bourguignon and coq au vin, plus a casserole of scalloped oysters made with sherry. They found that anywhere from 4 to 49 percent of the original alcohol remained in the finished dishes, depending on the type of food and the cooking method.

Higher temperatures, longer cooking times, uncovered pans, wider pans, top-of-the-stove rather than closed-oven cooking—all conditions that increase the general amount of evaporation of both water and alcohol—were found, not surprisingly, to increase the loss of alcohol.

Do you think you're burning off all the alcohol as you march triumphantly into your darkened dining room bearing a tray of blazing cherries jubilee or crêpes suzette? Well, think again. According to the 1992 test results, you may be burning off only about 20 percent of the alcohol before the flame goes out. That's because in order to sustain a flame, the percentage of alcohol in the vapor must be above a certain level. Remember that you had to use a high-proof brandy and warm it to make more alcohol vapor before it would even ignite. (You can't light wine, for example.) When the alcohol burns down to a certain, still-substantial level in the dish, the fumes are no longer flammable and your fire goes out. That's show biz.

How much weight should you give these test results when trying to accommodate your guests?

One thing you should consider is the dilution factor. If your recipe for six servings of coq au vin calls for 3 cups of wine, and if about half of the alcohol cooks off during a 30-minute simmer (as the researchers found), each serving will wind up with the amount of alcohol in two ounces of wine. On the other hand, those same 3 cups of wine in a six-serving boeuf bourguignon that simmers for three hours and loses 95 percent of its alcohol (according to the test results) will wind up giving each diner the alcohol equivalent of only two-tenths of an ounce of wine.

Still, some alcohol is still alcohol. Use your judgment.

Copyright © 2002 Robert L. Wolke. All rights reserved.