What Einstein Kept Under His Hat: Secrets of Science in the Kitchen (42 page)

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Y
our suspicions are well founded.

Real vanilla has always been expensive because wresting it from nature is a time- and labor-consuming enterprise and because it is grown in faraway lands. And like cacao, cashew nuts, and coffee beans, vanilla is a commodity subject to the vagaries of nature and to the laws of supply and demand. All four of these highly esteemed indulgences come from tropical latitudes, where storms periodically decimate crops and thus affect prices all over the world.

I can’t explain economics (I sometimes think nobody can), but what I can do is explain the nature of real vanilla, how it differs from imitation vanilla, and what the Mexican products may or may not consist of.

First, real vanilla.

Vanilla beans are not beans. They’re the fermented and dried seed pods (fruits) from one of two species of climbing-vine orchid plants,
Vanilla tahitensis,
native to the Pacific Islands, or
Vanilla planifolia,
native to Mexico. The Aztecs in Mexico were the first to marry vanilla’s flavor with the seeds of another native plant, the one we now know as chocolate. (Talk about marriages made in heaven!) The Spanish conquistadors came up with the word
vainilla
, meaning “little scabbard, sheath, or pod,” referring to the shape of the vanilla bean.

Today, about three-quarters of the world’s vanilla production is of the Mexican
V. planifolia
variety but grown on the islands of Madagascar, the Comoros, and Réunion in the Indian Ocean. In the early nineteenth century these islands were under the rule of the Bourbon kings of France, and the vanilla from this region is still known as Bourbon vanilla. (No relation to you know what.)

When the vanilla orchid plant blooms, it produces only a few flowers at a time. Each flower opens in the morning, closes in the afternoon, and if not pollinated drops dead from the vine the following day. If it is to bear its valuable fruit it must be pollinated during the morning hours of its day of glory.

How, then, did vanilla plants manage to reproduce and survive for eons before humans came along and tried to cultivate them? Attempts to grow vanilla in parts of the world other than Mexico were unsuccessful for about three hundred years. Eventually it was discovered that a small bee of the genus
Melipona
, native only to Mexico, had been quietly doing the pollination job, as bees are wont to do. Today, almost all vanilla flowers in both Mexico and Madagascar are pollinated by human hands, using thin slivers of wood inserted precisely into each flower at precisely the right time. No bee was ever so meticulous. (Are you beginning to understand why vanilla is so expensive?)

When the vanilla pod reaches its maximum length of about 8 inches, it is harvested, dried in the sun for 10 to 30 days, and covered at night to sweat and ferment. Only then will the pods have developed their magnificent flavor and aroma.

Some 170 different chemicals have been identified in the aroma of vanilla, but most of it comes from the aromatic phenolic compound vanillin. Fortunately or unfortunately, humans can make vanillin much more efficiently than vanilla plants can. It can be synthesized from eugenol, the principal aromatic constituent of clove oil, or from guaiacol, a chemical found in tropical tree resins. Vanillin can also be made from lignin, a structural component of woody plants and a by-product of the manufacture of paper from wood pulp. But vanillin is no longer made that way in the United States or Canada because the process is environmentally unacceptable.

Synthetic vanillin is the main ingredient in artificial or “imitation” vanilla, which costs much less than real vanilla extract and is actually not too bad a substitute for the real thing, although it lacks the complexity of natural vanilla flavor. Synthetic vanillin used as a flavoring in packaged foods must be labeled as an artificial flavor. (But see “It’s a natural—or is it?” on p. 422.)

Whole vanilla beans are sold in airtight containers to keep them from drying out and losing their flowery bouquet. They should be as dark and soft as a stick of licorice candy, not too hard or leathery. Most of the flavor resides in and around the thousands of almost microscopic seeds, which can be exposed by slitting the bean lengthwise. They can be scraped out with the tip of a knife and added to custards, sauces, and batters. But the seed-shorn pod still contains a lot of flavor. Bury it in a jar of sugar, tightly covered, and leave it for a couple of weeks. Use the vanilla-suffused sugar in, well, custards, sauces, and batters.

Vanilla extract is much more convenient to use than whole beans. In its inimitable bureaucratic style, the FDA defines Pure Vanilla Extract as “the solution in aqueous ethyl alcohol of the sapid and odorous principles extractable from vanilla beans.” To be labeled as such it must have an alcohol content of at least 35 percent by volume (higher concentration of alcohol extracts more of vanilla’s subtle flavor) and be made from no less than 13.35 ounces of vanilla beans per gallon. (Don’t ask.) It may contain sugar and other ingredients such as glycerin or propylene glycol for smoothness, but if it contains added synthetic vanillin, it must be labeled Imitation Vanilla Flavoring.

And finally, the Mexican connection.

Mexico lost its world leadership in vanilla production when the revolution of 1910 destroyed most of its Gulf Coast vanilla plantations. But its reputation lingers on, and Mexican “vanilla extract” is widely available. But because labeling laws aren’t enforced in Mexico as strictly as they are in the United States, Mexican “vanilla extract” may be a vanillin-based imitation flavoring.

Worse yet, some Mexican and Caribbean vanilla products might contain coumarin (1,2-benzopyrone), which is extracted from the beanlike seeds of the tonka tree,
Dipteryx odorata
(
cumaru
in Spanish). Coumarin has a strong vanilla-like aroma but is toxic; under the name warfarin it is used as rat poison because it thins the blood and the poisoned rats bleed to death internally. As the drug coumadin, it is used as an anticoagulant in the treatment of heart disease.

Coumarin was completely banned as a food additive by the FDA in 1954.

The bottom-line caveat is this: Be wary of Mexican and Caribbean “vanilla” liquids. At best, they may be imitation, made from synthetic vanillin, and at worst, they may contain coumarin. In theory, the FDA is supposed to block the import of coumarin-containing products, but coumarin has been found in some imports that slipped through.

Chapter Nine

Galley Gear

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W
HETHER CALLED
a kitchen, galley, caboose, chuckwagon, or cookhouse, and whether situated in a home or restaurant, on a ship, freight train, or wagon train, or even outdoors wherever a shelter can be set up, it is a place dedicated to the vital task of preparing food for anyone from a sole diner to an army. Its barest essentials are a few pots of clay or metal, sources of heat and water, and perhaps a knife. All else is excess.

And in today’s kitchens, boy, do we have excess!

We have refrigerators; gas, electric, and induction ranges; convection and microwave ovens; mixers; blenders; nonstick cookware; and—well, just look around your kitchen, you lucky dog. You’ve come a long way, baby.

But just as these tools have to be in proper shape to deal with a variety of foods, we have to know how to deal with the tools themselves. There is nothing more frustrating to a craftsman than having to repair a tool before being able to use it.

Does your dishwasher eat your aluminum utensils? Does your refrigerator exude an uninvited fragrance? Does your butter keeper spoil your butter? Does your oven cook a roast faster or slower than the recipe says? Do your pizzas come out flabby and your cakes goopy?

It’s all in how you use your armamentarium of appliances, apparatuses, equipment, tackle, gear, gadgets, and utensils. Treat them with understanding and respect, for as Emerson wrote, “If you do not use the tools, they use you.”

Or, to paraphrase Thoreau, you become the tools of your tools.

I’ve always kept an open box of baking soda in my refrigerator to absorb odors. But I’ve noticed that there’s now a new kind of baking soda box in the supermarket that supposedly works even better, even though the label says it contains nothing but pure baking soda. How does baking soda absorb odors, and how does this new contraption do it better?

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L
ike every other householder in this country, I have religiously kept an open box of Arm & Hammer (is there any other kind?) baking soda in my refrigerator, and I can testify that I have never smelled a bad odor. It must also have worked to repel tigers, because not once did I encounter a tiger in my house as long as that baking soda box was in the fridge.

Is it possible that I never saw a tiger because I live so far from India, or that I never smelled a foul odor in my refrigerator because I’m such a fastidious fridgemeister? Nah! Not according to the Arm & Hammer Division of Church & Dwight Co., Inc., and every domestic maven in the U.S.A., who would staunchly maintain that the baking soda absorbed all the odors. (They make no claims about tigers.)

What hard evidence do we have that baking soda really works, at least for odors? None that I know of. But here’s the theory.

Baking soda is pure sodium bicarbonate(NaHCO
3
), also known as bicarbonate of soda. It reacts with both acids and bases, that is, with both acidic and alkaline chemicals. (The bicarbonate ion is
amphoteric
.) But it is more than twenty times as effective in reacting with acids as with bases. And thereby hangs the odor-eating theory. Should a wandering molecule of a smelly acid alight upon a surface of baking soda, it will be neutralized, turned into a salt (shades of Lot’s wife!), and trapped permanently. True enough. There is no arguing with the fact that baking soda will gobble up acids—if given the opportunity. But there’s the rub, or rubs. How do we get the acid to come into contact with the baking soda, and why do we want to trap acids anyway?

First, why are acids the alleged stinkers? It goes back mostly to spoiled milk. In the old days of undependable refrigeration, and especially before pasteurization, milk quickly spoiled, not only by bacterial growth but by its butterfat breaking down into fatty acids, primarily butyric, caproic, and caprylic acids. Butyric acid is largely responsible for the odor of rancid butter, whereas caproic and caprylic acids are named after what they smell like:
caper
is Latin for goat. Get the drift?

So if you are in the habit of leaving month-old milk in the refrigerator for several weeks while you visit your time-share, many of the sour fatty acid molecules may indeed find their way to an open box of baking soda, fall in, and be neutralized.

But not all smelly molecules (smellicules?) that can pollute your refrigerator’s air space are acids, or even bases (alkalis) for that matter; chemically speaking, they can be virtually anything. Claiming that baking soda absorbs “odors” generically is stretching the truth by a chemical mile.

Let’s put it this way: An odor is a puff of gaseous molecules floating through the air to our noses. Each type of molecule has its unique chemical identity and its own unique set of reactions with other chemicals. No single chemical, sodium bicarbonate included, can claim to react with and deactivate any and all gaseous chemicals that happen to smell bad.

Even for acidic odors that are bicarbonate’s main quarry, note that the landing pad for a smellicule on a box of baking soda is a mere 7 square inches (the box-top area) located at some random position within a 20-cubic-foot (35,000-cubic-inch) refrigerator air space. That’s not a very efficient system for capturing smellicules. The box does not
attract
odors, as many people believe. It has no come-hither power, in spite of its toplessness.

The new “contraption” you saw is Arm & Hammer’s creatively spelled Fridge-n-Freezer Flo-Thru Freshener, a standard one-pound box of baking soda with removable sides, intended to give gaseous molecules more access to the baking soda by “flo-ing thru” porous paper inner seals. That sounds like a great idea, but this box, “specially designed to expose more baking soda than any other package,” uncovers only another 7 square inches of baking soda surface. And the air in the fridge doesn’t “flo thru” the package anyway. There is no fan or other force blowing it into one side of the box and out the other. Nice advertising concept, though.

In short, as it says on Arm & Hammer’s website, “Arm & Hammer Baking Soda’s deodorization power is legendary!”

I agree. It’s a legend.

What about the odor molecules that baking soda won’t absorb? There is only one common substance that can gobble them all up indiscriminately: activated charcoal. It works not by trying to be a chemical for all seasons, but by using a physical stickiness that is essentially chemistry-blind. If gases find their way into its enormous interior network of microscopic pores, they stick by a phenomenon called adsorption, the adhesion of molecules to a surface by means of what chemists call van der Waals forces.

Charcoal is made by heating hardwood, nutshells, coconut husks, animal bones, or other carbon-containing materials in an oxygen-free environment, so that they don’t actually burn, while substances other than carbon are driven off. It is then “activated” by being treated with very high temperature steam, a process that removes any remaining noncarbon substances and results in an extremely porous microstructure within the charcoal grains. A single gram (one twenty-eighth of an ounce) of activated charcoal may contain up to 2,000 square meters (18,000 square feet) of internal surface area.

You may be able to find activated charcoal (the best kind is made from coconut husks) in a drugstore, hardware store, appliance store, or pet shop. Spread it out on a baking pan with sides, and leave it in the offending fridge for a couple of days. Do
not
use charcoal briquettes; they contain coal, sawdust, and other substances, and their charcoal content wouldn’t work anyway because it isn’t powdered or activated.

In the end, there is only one sure-fire route to a sweet, odor-free refrigerator. Three words: prevention, prevention, prevention. Seal all your refrigerated food, especially “strong” foods such as onions, in airtight containers. Check frequently for signs of spoilage, round up the usual suspects, and throw them away. Wipe up spills promptly. Clean the fridge thoroughly. Yeah, I know, but do it more often.

Oh, you say there was a power outage while you were on vacation and all your refrigerated food spoiled and you could smell it all the way from the airport on your return? Poor soul. Neither baking soda nor charcoal will help, nor will cursing the power company. Make yourself a stiff drink, go to Louisiana State University’s disaster information website http://www.lsuagcenter.com/Communications/pdfs_bak/pub2527Q.pdf, and follow the directions.

Sticks of butter stored in a covered glass butter dish in the butter-keeper compartment in the door of our refrigerator develop a dark yellow, slightly rancid-tasting skin. Is there any way to prevent this?

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Y
ou probably think you’re doing everything right, don’t you? Well, the worst place to keep butter is in a butter dish, and the worst place to keep the butter dish is in the “butter keeper” of your refrigerator.

Butter dishes were invented to facilitate serving, not preserving. Because they’re not airtight, the butter’s surface is exposed to air and can oxidize and become rancid.

Butter compartments should be banned. Many of them have little heaters inside to keep the butter at a slightly warmer temperature than the rest of the fridge to make it easier to spread. But the warmer temperature speeds up oxidation of the fat.

I keep my butter in the freezer compartment, tightly enveloped in plastic wrap. Yes, it’s hard as a rock when I want to use it, but a sharp knife can whack off a piece that will warm up and soften rather quickly.

I’ve always wondered why some foods go bad so quickly even if refrigerated, while others seem to last forever without refrigeration. Things like opened mustard and ketchup bottles can last for weeks outside the refrigerator, and cheese, honey, and peanut butter can survive at room temperature for even longer. Is there any general way to estimate how long a food will last?

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W
ould that life were that simple! There can be no single rule that covers all the foods we consume—an almost infinite number of combinations of thousands of different proteins, carbohydrates, fats, and minerals that make up our omnivorous diet. “Going bad” can refer to the effects of bacteria, molds, and yeasts; heat; oxidation from exposure to air; or enzymes in the foods themselves. Enzymes in fruits, for example, are there specifically to hasten their ripening, maturing, and ultimate decay.

One thing is inevitable, however: all foods will eventually spoil, rot, decompose, disintegrate, crumble, putrefy, turn rancid, or become just plain yucky. It’s Nature’s law, for dust they art and unto dust shalt they return. Proteins will turn soft, squishy, putrid, and green; carbohydrates will ferment and sour; fats will turn rancid. Ketchup and mustard keep so long because they contain microbe-inhibiting acid (vinegar), no fat, and no active enzymes.

In battling food spoilage, we humans have cooked our foods, smoked them, dried them, acidified them, and salted or sugared them—and, thanks largely to an American inventor named Clarence Birdseye (yes, that was really his name), in recent decades we have frozen them.

During a stint as a fur trader in Labrador, Birdseye watched the native people freeze fish and meats for later consumption. He noted that when frozen quickly in the winter instead of more slowly during the milder times, the food retained better texture, flavor, and color when thawed.

In 1925, Birdseye unveiled his “Quick Freeze Machine,” and the frozen-food industry was off and running. Today, Birds Eye Foods bills itself as the nation’s largest processor of frozen vegetables. And no, there never was a Mr. Jolly Greengiant.

Freezing preserves foods because the frozen water, a.k.a. ice, is unavailable for use by spoilage microorganisms, so they can’t grow. Refrigeration, as distinguished from freezing, will slow their growth, but there are limits. At a typical home-refrigerator temperature, ten thousand bacteria can become ten billion in a few days.

Enter preservatives: chemicals added to prepared foods to extend their shelf lives—and the lives of us who eat them. Yes, preservatives are chemicals. And yes, they are also additives, because, obviously, they have been added. (So have salt, sugar, spices, vitamins, and so on.) Quite simply, without preservatives most of our foods would spoil. And yet we are continually wooed by food labels demurely hinting at their superiority with the phrase “Contains no additives or preservatives.” Someday I’d like to see a label that adds “Will spoil almost as soon as you get it home.”

What are these chemicals? They fall mostly into four categories.

•
 Antimicrobials
inhibit the growth of bacteria, molds, and yeasts. They include the sulfur dioxide and sulfites used in fruits, fruit juices, vinegars, and wines; sorbic acid used in cheeses; calcium propionate and other propionates used to inhibit molds in bread and other baked goods; and sodium and other benzoates used to prevent fungal growth in beverages, fruit preserves, cheeses, pickles, and many other products. Benzoates occur naturally in cranberries, while propionates can be found in strawberries, apples, and cheeses.

•
 
Antioxidants
inhibit oxidation by air, which makes fats, especially unsaturated fats, turn rancid. They include sulfites (again), BHA (
butylated hydroxyanisole
), BHT (
butylated hydroxytoluene
), TBHQ (
tertiary butylated hydroquinone
), ascorbic acid (vitamin C), and propyl gallate. They’re used in potato chips, nuts, cereals, and crackers.