What Einstein Told His Cook (12 page)

CAUTION: FAT NOODLES AHEAD

I enjoy eating ramen noodles, but I’ve noticed that they contain a lot of sodium and fat per serving. Is it the noodles or the flavor mix that contains the fat?

T
he ingredients in the noodles and in the package of flavorings are listed separately, so you can easily find out which contains what. The salt (usually lots of it) is in the flavorings. You might not expect the noodles to contain fat, but surprisingly, that’s where most of it is hiding.

I know you’ve always wondered how they make that compact, rectangular block of perfectly intertwined curlicues, and so have I, so here’s what your question has stimulated me to find out.

The dough is first extruded through a row of nozzles to make a ribbon of long, side-by-side wavy strands. The ribbon is then cut to length and folded over onto itself, after which it is held in a mold while being deep-fried, which dries out the noodles so that the block will hold its convoluted shape ever after. The deep frying, of course, adds fat to the noodles, and although there may be a small amount of oil in some seasoning mixes, virtually all of the fat is therefore in the noodles.

A few brands of ramen noodles are air-dried instead of being fried, but unless it says so on the package, the only way to tell is the absence of fat in the noodles’ ingredient list. A little arithmetic applied to the Nutrition Facts charts on the labels of four leading brands showed that, except for the hot water, the ingredients in a bowl of ramen soup ranged from 17 to 24 percent fat. So if you think that ramen noodles are “just pasta,” you may want to think again.

A SURE-THING BAR BET

A friend wanted to bet me that heavy cream weighs less than light cream. Should I have taken the bet?

N
o. You would have lost.

Heavy cream contains a higher percentage of milk fat (usually called butterfat, because butter can be made from it) than light cream does: 36 to 40 percent fat in heavy whipping cream versus only 18 to 30 percent in light cream. (And, if you’re interested, the heavy cream can contain up to twice as much cholesterol.) But volume for volume, fats weigh less than water; they’re less dense. So the higher the percentage of fat in a water-based liquid, the lighter the whole liquid will be.

It’s not a huge difference. In my kitchen laboratory, a pint of heavy whipping cream weighed 475.0 grams, while a pint of light cream weighed 476.4 grams: three-tenths of a percent heavier.

The names “heavy” and “light” as related to cream were never meant to signify weight; they apply to richness or thickness. Fattier substances are thicker—more viscous—and therefore feel more substantial or “heavier” on the tongue.

CUTTING FAT

How do they homogenize milk?

S
ome of my older readers may remember milk delivered to the doorstep in bottles. (I’ve read about it in my history books.) The milk had a separate layer of cream at the top. Why? Because cream is just milk with a higher proportion of butterfat and, because fat is lighter (less dense) than water, it floats to the top. We—I mean, those oldtimers—had to shake the bottle vigorously to distribute the creaminess uniformly.

If the fat globules could be chopped up into small enough “globulettes”—around 80 millionths of an inch in diameter, they wouldn’t rise; they would be kept suspended in place because water molecules would be bombarding them from all directions.

To accomplish this, the milk is shot out of a pipe at a pressure of 2500 pounds per square inch at a metal sieve, coming out the other side as a fine spray containing fat particles tiny enough to stay suspended.

Yogurt and ice cream are usually made from homogenized milk, but butter and cheese are not, because we want the butterfat globules to be able to join together into a separate fraction.

PASTEUR REVISITED

All the milk and cream in my supermarket these days claim to be “ultra pasteurized.” What happened to plain, old “pasteurized”? Didn’t it kill enough germs?

I
welcome this question because it solves an old problem for me.

Back in 1986, during a six-month residence in the South of France, I saw something I had never seen in the U.S. The supermarkets kept their milk on the shelves without refrigeration. Instead of bottles or cartons, it was packaged in brick-shaped, cardboard-like boxes.

How can they do that, I wondered. Granted, milk is not the preferred beverage in France, but how do they get away with treating it in such a cavalier manner? Doesn’t it spoil? I promised myself to find out as soon as I returned to the States, but I seem to have procrastinated a bit.

The glass milk bottle, invented in 1884, began to be replaced after World War II by wax-coated paperboard cartons. The wax has since been replaced with a plastic coating, and today the coated paper carton competes with all-plastic, translucent jugs, especially in the larger sizes. Those brick-shaped, non-refrigerated containers are called aseptic packaging, which means, of course, germ-free packaging.

But isn’t all the milk that we buy in this country germ-free? Surprisingly, no, even though it has all been pasteurized in one way or another. There is a difference between killing all the germs dead and keeping the few that survive from multiplying.

The objective of pasteurization is to kill or deactivate all disease-causing microorganisms by “cooking” them. Just as you can roast a chicken at a relatively low temperature for a long time or at a higher temperature for a shorter time, effective pasteurization can be accomplished at a variety of time-and-temperature combinations. Traditional pasteurization, originally intended primarily to kill tuberculosis bacilli, involved heating the milk to 145–150ºF and holding it there for 30 minutes. Traditional pasteurization isn’t used much anymore, because it doesn’t kill and deactivate heat-resistant bacteria such as Lactobacillus and Streptococcus. That’s why ordinary pasteurized milk still has to be refrigerated.

Then came flash pasteurization, which keeps the milk at 162ºF for only 15 seconds. But today, modern dairy processing machinery can achieve sterilization by flash-heating it to 280ºF for a mere two seconds. It’s done by passing the milk through the thin spaces between hot, parallel plates, and then chilling it rapidly to 38ºF. That’s ultra pasteurization. Ultra pasteurized milk and cream still have to be refrigerated, but their shelf life is increased from 14 to 18 days to 50 to 60 days, depending on the refrigerator temperature. (It should never be higher than 40ºF.)

Did I say that ultra pasteurization heats the milk to 280ºF? Yes. But wouldn’t the milk boil first? Yes, it would, if it were in a container open to the atmosphere. But just as a pressure cooker raises the boiling point of water, the pasteurization equipment heats the milk under a high gas pressure that keeps it from boiling normally.

Europe has been ahead of us in adopting ultra pasteurization, and it is ahead of us in adopting aseptic packaging—those milk bricks I saw in France. In aseptic packaging, the milk is sterilized at high temperature for a short time as in ultra pasteurization, and then sent to the containers and the packaging machinery, both of which had been sterilized separately with steam or hydrogen peroxide. The filling and sealing are done under sterile conditions. The resulting product has an unrefrigerated shelf life of several months or even up to a year. Moreover, because the package is hermetically sealed with no air inside, the butterfat won’t turn rancid from oxidation.

In our American markets, we rarely see aseptically packaged milk or cream. We see aseptic packaging mainly in soy milk products and tofu in the organic and “health food” sections, and in those little “drink boxes” of juice. In Europe, aseptic packaging is more widely used, perhaps because it is more energy-efficient. The foods don’t have to be refrigerated during transportation and the packages are lighter than if steel cans or glass bottles had been used. Another reason, industry sources tell me, is that American consumers just don’t trust milk that isn’t refrigerated. But many consumers have told me that high-temperature pasteurized milk has an unpleasant, cooked flavor.

No matter how your milk or cream has been pasteurized or packaged, it does have an expiration date, even as you and I. Always check the date printed on the package.

I
T’S A THREADBARE CLICHÉ
that cooking is chemistry. True, the application of heat to foods causes chemical reactions to take place, resulting in chemical changes that we devoutly hope will enhance flavor, texture, and digestibility. But the art of cooking, as distinguished from the craft, lies in knowing which “reactant” ingredients to combine, and how to combine and manipulate them to produce the most gratifying chemical changes.

Is that still too unromantic a characterization of one of life’s greatest pleasures? Of course. But the fact remains that all foods are chemicals. Carbohydrates, fats, proteins, vitamins, and minerals are all made up of those tiny chemical units called molecules and ions. A vast variety of different molecules plays a vast number of different roles in the mélange of almost infinitely complex chemical reactions we call cooking, metabolism, and indeed, life itself.

Besides the primary nutrients, there are many other substances—chemicals—that we encounter in cooking. In this chapter we look at some of the “chemicals in our foods,” not with the frightening implications that are sometimes attached to that phrase by opponents of food additives but in recognition of the fact that ultimately our foods are nothing
but
chemicals. Pure water or H
₂
O is, of course, the most important chemical of all.

CLEARING UP WATER FILTERS

What, exactly, do water filters do? I bought a Brita pitcher and it claims to eliminate things like lead and copper with “ion exchange resins,” whatever they are. Do they also remove useful things like fluoride?

T
he name “water filter” is misleading. The word
filtered
literally means only that the water has passed through a medium containing tiny holes or fine passageways that screen out suspended particles. When traveling in a country whose water supply is suspect and you ask a waiter whether the water is filtered, an affirmative reply may mean little more than that you can see through it.

Here at home,
filter
has become a generic word for a device that does more than clarify the water; it purifies it by removing tastes, odors, toxic chemicals, and pathogenic microorganisms. The idea is to make sure the water is safe and palatable.

Your nose and palate will tell you whether you want to remove odors and tastes. As far as toxic chemicals and pathogens are concerned, an analysis can be provided by many local water companies or independent labs. Depending on your degree of paranoia, you may feel like searching for a filter that will remove everything from the water but its wetness. Keep in mind, though, that it’s a waste of money to buy a device to remove things that aren’t there. Continually replacing the cartridges can be expensive.

What kinds of “bad stuff” can contaminate water? Industrial and agricultural chemicals; chlorine and its byproducts; metal ions; and cysts, which are tiny chlorine-resistant capsules of protozoan parasites such as cryptosporidium and giardia that can cause abdominal cramping, diarrhea, and even more serious symptoms in people with weakened immune systems.

Cryptosporidium and giardia cysts are generally bigger than one micron or 40 millionths of an inch, so any barrier with holes smaller than that will screen them out. But not all filter devices contain such particle filters, so if these contaminants are of concern to you, check the product’s literature to see if the performance claims include cyst reduction.

Commercial water filters, which may be either batch-at-a-time pitchers or attachments to faucets or supply lines, remove other contaminants in three ways: with charcoal, with ion exchange resins, and with actual particle filters.

The workhorse of most water filters is activated charcoal, a material that has a prodigious and indiscriminate appetite for chemicals in general and gases (including chlorine) in particular. Charcoal is made by heating organic matter such as wood in a limited supply of air, so that it decomposes into porous carbon but doesn’t actually burn. Depending on how it is manufactured, the charcoal can contain an enormous amount of microscopic internal surface area. An ounce of so-called activated charcoal—the best kind is made from coconut shells—can contain some 2,000 square feet of surface area. That surface area makes a highly attractive landing field for wandering molecules of impurities in water or air, and when they land they stick.

Activated charcoal is used to adsorb colored impurities from sugar solutions and to adsorb poisonous gases in gas masks. (That wasn’t a misprint.
Adsorption
, with a “d,” is the sticking of individual molecules to a surface, while
absorption
, with a “b,” is the wholesale soaking up of a substance. Charcoal adsorbs; sponges absorb.) In water filters, the charcoal removes chlorine and other odoriferous gases and a variety of chemicals such as herbicides and pesticides.

Now about those ion exchange resins. They’re little plastic-like granules that remove metals such as lead, copper, mercury, zinc, and cadmium. These are, of course, not present in the water as chunks of metal but as
ions
.

When a chemical compound of a metal dissolves in water, the metal goes into solution in the form of ions: positively charged atoms. We can’t just pluck these ions out of the water with charcoal, for example, because removing positive charges would leave the water with a surplus of negative charge, and Nature makes that a very costly operation in terms of expended energy; she vastly prefers that the world remain electrically neutral.

What we
can
do is exchange those positive ions for other, more harmless positive ions: sodium ions or hydrogen ions, for example. That’s what an ion exchange resin does. It contains loosely bound sodium or hydrogen ions that can swap places with metal ions in the water, leaving the metals effectively trapped in the resin. The resin (as well as the charcoal) eventually becomes fully loaded with contaminants and must be replaced. How long it continues to work depends on how contaminated your water is. If your water is hard, the ion exchange resin will also remove calcium and magnesium ions, and you’ll have to replace it sooner.

Most domestic water filters contain both activated charcoal and an ion exchange resin, usually mixed together into a single cartridge. They therefore remove metals and other chemicals, but not necessarily pathogenic cysts. As I’ve said, check the claims about cysts in the product literature.

Do the purification filters remove fluoride? Generally, no. Fluoride is a negatively charged ion, not a positively charged one. So it is ignored by the ion exchange resin, which has only positive ions to swap. But when a filter cartridge is new, some fluoride may be removed from the first gallon or two, presumably by adsorption on the charcoal. After that, however, the filter doesn’t remove fluoride.

THE WHITE POWDER TWINS

Some recipes call for baking soda, some for baking powder, and some even call for both. What’s the difference?

I
t’s all in the chemicals.

Baking soda (aka bicarbonate of soda) is a single chemical: pure sodium bicarbonate, whereas baking powder is baking soda combined with one or more acid salts, such as monocalcium phosphate monohydrate, dicalcium phosphate dihydrate, sodium aluminum sulfate, or sodium aluminum phosphate.

Now that I’ve warmed the hearts of chemistry fans and confounded the rest of my readers, let me try to win the latter back.

Both baking soda and baking powder are used for leavening (from the Latin
levere
, meaning to raise or make light): making baked goods rise by producing millions of tiny bubbles of carbon dioxide gas. The gas bubbles are released within the wet batter, after which the heat of the oven expands them until the heat firms up the batter and traps them in place. The result is (hopefully) a light, spongy cake instead of a dense, gummy mess.

Here’s how these two confusingly named leavening agents work.

Baking
soda
releases carbon dioxide gas as soon as it comes in contact with any acidic liquid, such as buttermilk, sour cream, or, for that matter, sulfuric acid (not recommended). All carbonates and bicarbonates do that.

Baking
powder
, on the other hand, is baking soda with a dry acid already mixed in. It is used when a recipe contains no other acid ingredients. As soon as the powder gets wet, the two chemicals begin to dissolve and react with each other to produce carbon dioxide. To keep them from “going off” prematurely, they have to be protected zealously from atmospheric moisture by being kept in a tightly closed container.

In most cases, we don’t want our baking powder to release all its gas as soon as we mix the batter—before it has been baked enough to trap the bubbles in place. So we buy a “double-acting” baking powder (and most of them are, these days, whether the label says so or not), which releases only a portion of its gas when it gets wet and releases the rest only after reaching a high temperature in the oven. Generally, two different chemicals in the powder are responsible for the two reactions.

But why would a recipe call for
both
baking soda and baking powder? In this case the cake or cookie is actually being leavened by the baking powder, which contains exactly the right proportions of bicarbonate and acid to react completely with each other. But if there happens to be an acid ingredient such as buttermilk present that would upset that balance, some extra bicarbonate in the form of baking soda is used to neutralize the excess acid. (Ask any chemist about this, but walk briskly away if he or she utters the word
titration
.)

Commercial bakers mix up their own witch’s brews of leavening chemicals, designed to release just the right amounts of gas at just the right times and temperatures during the baking process. At home, the safest course is simply not to tamper with a well-tested recipe; use the prescribed amount(s) of whatever leavening agent(s) it calls for.

DOES ALUMINUM CAUSE WHAT’S-HIS-NAME’S DISEASE?

The label on my baking powder can says it contains sodium aluminum sulfate. But isn’t aluminum dangerous to eat?

S
odium aluminum sulfate and several other aluminum compounds are listed by the FDA as GRAS: Generally Regarded as Safe.

About twenty years ago, one study found increased levels of aluminum in the brains of deceased Alzheimer’s victims. Ever since then, suspicions have been circulating that aluminum, whether in food or water or dissolved from aluminum cookware by acidic foods such as tomatoes, causes Alzheimer’s, Parkinson’s, and/or Lou Gehrig’s diseases.

A great deal of subsequent research has been done, with conflicting and contradictory results. At this writing, the Alzheimer’s Association, the FDA, and Health Canada, the Canadian federal department of health, all agree that there is as yet no verifiable scientific evidence for a relationship between aluminum ingestion and Alzheimer’s disease, and that there is therefore no reason for people to avoid aluminum. In the words of the Alzheimer’s Association, “The exact role (if any) of aluminum in Alzheimer’s disease is still being researched and debated. However, most researchers believe that not enough evidence exists to consider aluminum a risk factor for Alzheimer’s or a cause of dementia.”

As one of millions of people afflicted with chronic heartburn, I swallowed large doses of Maalox (MAgnesium ALuminum hydrOXide) and similar aluminum-containing antacids for many years before the new anti-reflux drugs were invented. Yet I have no signs whatsoever of Alzheimer’s disease.

Now, what was your question?

AMMONIA, WE’VE HARDLY KNOWN YA

I have an old recipe that calls for baking ammonia. What is it?

A
mmonia itself is an acrid-smelling gas, usually dissolved in water and used for laundry and cleaning purposes. But baking ammonia is ammonium bicarbonate, a leavening agent that when heated breaks down into three gases: water vapor, carbon dioxide, and ammonia. It isn’t used much anymore—if you can even find it—because the ammonia gas can impart a bitter taste if it isn’t all driven off during baking. Commercial cookie bakers can use it because flat cookies have a large surface area for the gas to escape from.

SOUR POWER

My mother’s recipe for stuffed cabbage calls for sour salt. None of the stores I’ve tried knows what it is. Come to think of it, neither do I. What is it and where can I get some?

S
our salt is misnamed. It has nothing to do with table salt or sodium chloride. In fact, it isn’t a salt at all; it’s an acid. They’re two different classes of chemicals.

Every acid is a unique chemical having properties that distinguish it from all other acids. But it can have dozens of derivatives called salts; every acid is the parent of a whole brood of salts. So-called sour salt is not one of those offspring salts but rather a parent acid in its own right: citric acid. It has an extremely sour flavor and is added for tartness to hundreds of prepared foods, from soft drinks to jams and frozen fruits.