What Einstein Told His Cook (5 page)

Starches and sugars are two families of chemicals that are very closely related. In fact, a starch molecule is made up of hundreds of smaller molecules of the simple sugar glucose, all tied together (see page 6). In principle, then, if we could chop cornstarch molecules up into small pieces, we could make hundreds of molecules of glucose. If the chopping-up isn’t quite complete, there will also be some maltose, another sugar that consists of two glucose molecules, still bonded together (a disaccharide). There will also be some even bigger fragments, consisting of dozens of glucose molecules, still bonded together (a polysaccharide). Because these bigger molecules can’t slide around past one another as easily as small molecules can, the final mixture will be thick and syrupy. Corn syrup. And that includes the bottled corn syrup in your supermarket. The dark syrup has a more intense, molasses-like flavor than the light syrup because it contains some refiners’ syrup, which is…well, molasses.

Almost any acid, as well as a variety of enzymes from plants and animals, can perform the trick of breaking starch molecules down into a syrup of mixed sugars. (An enzyme is a biochemical that helps a specific reaction to take place rapidly and efficiently. [Techspeak: It’s a natural catalyst.] Without enzymes, many essential life processes would be uselessly slow or just wouldn’t work at all.)

The common sugar contained in sugar cane, sugar beets, and maple syrup is sucrose. But a sugar by any other name may not taste as sweet. That is, the glucose and maltose in corn syrup are only about 56 percent and 40 percent as sweet, respectively, as sucrose. So if cornstarch is broken down, it may average out to perhaps 60 percent of the sweetness of sucrose.

Food manufacturers get around this by using yet another enzyme to convert some of the glucose into its alternative molecular form, fructose, a sugar that is 30% sweeter than sucrose. That’s why “high-fructose corn syrup” often appears on the labels of foods that need to be really sweet, such as sodas, jams, and jellies.

Corn sweeteners don’t taste quite the same as good old sucrose, because different sugars have slightly different kinds of sweetness. The flavors of fruit preserves and soft drinks, for example, just ain’t what they used to be before the food manufacturers pretty much abandoned cane sugar for corn sweeteners. As a label-reading consumer, all you can do is to choose products sweetened with the highest proportion of sucrose, which is listed on the label as “sugar.” (If there are other sugar ingredients in a product, they will be listed on the label as “sugars.”)

Next time you find yourself in a tropical, sugar-cane-producing country, buy some Coca-Cola. It is undoubtedly still made there with cane sugar, instead of the corn sweeteners that most U.S. bottlers have been using for more than a decade. Bring some home and compare its flavor with the contemporary American “Classic.”

But when the customs agent aks what’s in your bag, for heaven’s sake don’t say “Coke.”

BROWN AMBROSIA

Besides the amount of sugar, is there any difference between unsweetened chocolate, semisweet chocolate, and sweet chocolate?

Y
es. Let’s look at how chocolate is made.

Cacao beans, which are really seeds, are found inside melon-shaped seedpods attached directly to the trunk or thick branches of the tropical cacao tree. The beans are first separated from the pulpy mass inside the pod and allowed to ferment, usually by piling them up in heaps and covering them with leaves. Microbes and enzymes attack the pulp, kill the germs of the seeds (the parts that would germinate or grow), remove some of the bitter flavor, and darken the beans’ color from off-white to light brown.

The dried beans are then shipped off to Willy Wonka at the chocolate factory, where they are roasted to further improve their flavor and color, separated from their shells, and milled or ground. The frictional heat of grinding melts the beans’ substantial content—about 55 percent—of vegetable fat, euphemistically known as cocoa (not cacao) butter. The result is a thick, brown, bitter liquid called chocolate liquor: the ground-up solids suspended in melted fat. This is the starting material for making all chocolate products.

When cooled, chocolate liquor solidifies into the familiar unsweetened, or bitter, chocolate that’s sold in one-ounce “squares” for baking. The FDA requires that this basic unsweetened chocolate contain between 50 and 58 percent fat.

The fat and the solids can be separated, however, and mixed in various proportions with sugar and other ingredients to make hundreds of different chocolates with a wide range of flavors and properties.

One of the wonderful things about chocolate is that its fat melts at 86º to 97ºF, which is just below body temperature, so that at room temperature it is relatively hard and delightfully brittle, but it literally melts in the mouth, releasing maximum flavor and producing a smooth, velvety sensation.

Semisweet or bittersweet chocolate is a prepared mixture of chocolate liquor, cocoa butter, sugar, an emulsifier, and sometimes vanilla flavoring. When melted, it is more fluid than unsweetened chocolate and has a satin gloss, both of which qualities make it ideal for dipping. It is sold in “squares” or bars for cooking, but because it may contain only 35 percent fat (the presence of the sugar reduces the percentage of fat), it will have different cooking characteristics from the fattier unsweetened chocolate.

Thus, you can’t substitute unsweetened chocolate plus sugar for semisweet or bittersweet chocolate in a recipe. To further complicate things, there are significant variations among brands, and chocolates labeled bittersweet are likely to have a higher ratio of chocolate liquor to sugar than those labeled semisweet.

Moving up the sweetness scale, we encounter hundreds of kinds of semisweet and sweet chocolate confections containing at least 15 percent chocolate liquor and often much more. Milk chocolate generally contains less chocolate liquor (10 to 35 percent) than dark chocolate (30 to 80 percent) because the added milk solids reduce its percentage. That’s why milk chocolate has a milder, less bitter flavor than dark chocolate. The FDA sets ingredient standards for all of these products manufactured in the U.S.: sweet chocolate, semisweet or bittersweet chocolate, and milk chocolate.

Before any high-quality chocolate product is ready for molding into bars or for enrobing (coating) various objects, it goes through two important processes: conching and tempering. In conching, the chocolate mixture is kneaded in heated tanks at a controlled temperature somewhere between 130º and 190ºF (it varies) for as long as five days. This aerates the chocolate and drives off moisture and volatile acids, improving both its flavor and smoothness. Then it is tempered, kept at carefully controlled temperatures while it cools, so that the fat crystallizes into very tiny crystals (about 40 millionths of an inch), rather than bigger ones (as large as 2 thousandths of an inch) that would give the chocolate a grainy texture.

Today, there are many excellent chocolates available for cooking. The quality depends on many factors, including the blend of beans used (there are about 20 commercial grades); the type and extent of roasting; the degree of conching, tempering, and other processing; and, of course, the amounts of cocoa butter and other ingredients.

A DUTCH TREATMENT

What is Dutch process cocoa? How is it used differently from regular cocoa in recipes?

T
o make cocoa, unsweetened chocolate (solidified chocolate liquor) is pressed to squeeze out most of the fat, and the resulting cake is then ground to a powder. There are several types of “regular” cocoa powder, depending on how much fat remains. For example, “breakfast cocoa” or “high-fat cocoa,” as defined by the FDA, must contain at least 22 percent cocoa butter. If labeled just plain “cocoa,” it may contain anywhere between 10 and 22 percent fat. “Low-fat cocoa” must contain less than 10 percent fat.

In the Dutch process, invented in 1828 by Conrad J. van Houten in guess-what-country, either the roasted beans or the chocolate liquor cake is treated with an alkali (usually potassium carbonate), which darkens the color to a deep reddish brown and mellows the flavor. Hershey calls its Dutch-processed cocoa “European-style.”

Cocoa is naturally acidic, and the alkali used in the Dutch process neutralizes it. That can make a difference in a cake recipe, because acidic cocoa will react with any baking soda present to make carbon dioxide and increase leavening, but the neutralized Dutch process cocoa won’t.

Devil’s food cake is an interesting case because most recipes call for regular cocoa, yet the cake comes out with a devilish red color, as if it contained Dutch process cocoa. That’s because baking soda is used for leavening, and the alkaline baking soda “Dutches” the cocoa.

In the U.S., the word
cocoa
makes us think of a hot, chocolaty beverage. But a cup of what we call cocoa or hot chocolate is to a cup of hot Mexican chocolate what skim milk is to heavy cream, because we have squeezed out all the fat from the cocoa powder. A cup of Mexican chocolate, on the other hand, is thick and unimaginably rich because it is made from the whole chocolate liquor, fat and all.

In Oaxaca, in southern Mexico, a few years ago, I watched as the fermented and roasted cacao beans were ground with sugar, almonds, and cinnamon, emerging from the grinder as a glistening, thick brown paste—a sweetened and flavored chocolate liquor. It was then cast into round or cigar-shaped molds, cooled to solid cakes and sold in that form.

In the kitchen, one or two cakes of this Mexican chocolate are beaten into boiling-hot water or milk to make a rich, frothy nectar. In Oaxaca, it is served in widemouthed cups made specifically for dunking the egg-rich Mexican bread,
pan de yema
(yolk bread). In Spain, I have dunked
churros
, lengths of deep-fried pastry, into the same rich chocolate beverage.

Of the treasures that the Spanish
conquistadores
brought home from the New World, many would agree that in the long run, the chocolate was more valuable than the gold. Mexican chocolate is available in the United States under the brand names Ibarra and Abuelita.