Marlene Parrish - What Einstein Told His Cook 2

Technically, a foam is a suspension of gas bubbles in a liquid. The bubbles are so tiny (they are of colloidal size) that they never rise to the surface; they stay suspended in the liquid. Often, as in the case of marshmallow, polystyrene foam (trademarked Styrofoam), and baked meringues, we still call it a foam after the liquid has solidified or dried. Foams can be stabilized—the air bubbles prevented from coalescing into bigger bubbles—by emulsifying agents such as soaps and certain proteins. In foods, we prefer the protein stabilizers: gelatin, the casein in whipped cream, and the albumins in egg-white meringues can all do the job.

The most familiar brands of marshmallow confections, Campfire and Jet-Puffed, are in the shape of small cylinders about an inch in diameter and an inch long. Why that shape? In marshmallow factories the liquid foam is piped through a long, one-inch-diameter tube as it cools, and the emerging rope is then chopped into approximately one-inch lengths. (In case anyone ever asks you, Campfires are an eighth of an inch wider and an eighth of an inch shorter than Jet-Puffed marshmallows.)

By measuring and weighing them carefully (okay, so I’m a nut), I have calculated (a) that Campfire marshmallows are 23 percent puffier (less dense) than Jet-Puffed, and (b) that the 90 million pounds of marshmallows consumed annually in the United States would make a single marshmallow 30 yards in diameter and as tall as the Washington Monument.

The texture of marshmallow can be controlled by adjusting the proportions of ingredients and the amount of whipping. It ranges from the semiliquid Marshmallow Fluff to the more elastic and chewier marshmallows that can stand up to being coated with chocolate. That’s why chocolate-covered marshmallow candies are never as soft inside as you expect them to be.

You cannot have read this far without thinking about toasting marshmallows on a stick over a campfire, right? The fire’s heat both melts the gelatin and caramelizes the sugar, producing a hot, caramel-flavored goo that yin-yangs your tongue with heat and sweet. But as in all cooking, there is a right way and a wrong way.

Wrong way: Hold the marshmallow just above the flames until it catches fire, and let it burn until it has a crisp, black crust. Don’t be deterred by the fact that the crust is made of indigestible carbon laced with bitter-tasting and undoubtedly carcinogenic tars.

Right way: Wait until the fire has died down to glowing coals and then hold the marshmallow high over them, rotating it until it slowly develops a nice uniform tan color. (Patience, patience.) If it should catch fire, blow it out immediately, let it cool for a few seconds, and resume toasting.

In the Boy Scouts I learned to search out and cut a long green twig that wouldn’t catch fire. Today, you can buy a package of 30-inch-long Smorstix that are, according to the Smorstix website (http://www.smorstix.com), “made of 100% untreated white birch without any additives, dirt or grime.” With these, you can supposedly toast your marshmallows with a clear environmental conscience instead of “trampl[ing] the underbrush and damag[ing] trees and forests” (in Smorstix’s words) during your search for a toasting stick.

Ah, for the simpler, politically incorrect days of my youth!

My female readers are likely to know why Smorstix were so named: for s’mores, the Girl Scouts’ traditional campfire dessert made (according to the recipe in a 1927 Girl Scout manual) by inserting two toasted marshmallows between halves of a Hershey bar sandwiched between graham crackers. The hot, gooey marshmallow melts the chocolate, making even more goo.

For those who don’t have access to a campfire, I (don’t blame Marlene for it) have created Marshmallow Zaps, an indoor alternative to fire-roasted marshmallows.

Marshmallow Zaps

These marshmallow-caramel treats, crisp on the outside and soft on the inside, are not only a unique treat, but fun to watch while you’re making them. Look, Ma, no hands!

6 large (not miniature) marshmallows

About 2 tablespoons confectioners’ sugar

1.Arrange the marshmallows in a Stonehenge-style ring, placing them upright and well separated, on a microwave-safe dinner plate.

2.Zap the marshmallows in the microwave oven on high, watching through the window as they balloon to several times their size. Stop the oven when they have developed brown, volcano-like holes on top, after about 1½ minutes. (The time depends on the power of your microwave oven.)

3.Remove the plate carefully (it may be quite hot) and place it on the counter to cool completely, during which time the marshmallows will deflate and flatten.

4.Remove each Zap from the plate (it will be quite sticky), dip its bottom into confectioners’ sugar, and place it on a serving dish or platter. It will be crisp as a meringue on the outside and chewy on the inside, with a layer of brown caramelized sugar in the middle as if it were an inside-out fire-roasted marshmallow.

They may not look pretty, but you’ll sure want s’more.

Sidebar Science: How the Zaps work

IN THEinterior of the marshmallow, the microwaves’ energy converts water into steam, which first puffs up the marshmallow and then, when the gelatin’s elasticity limit is exceeded, breaks its way out through a hole it punches in the top.

Meanwhile, the sugar begins to caramelize under the influence of the heat. Because dehydration is the first step in the complex series of chemical reactions involved in caramelization, it is the dehydrated interior sugar that caramelizes first. The outer parts of the marshmallow, still saturated with steam, would not caramelize unless they were heated longer than in the Zaps recipe. As the marshmallows cool, the steam condenses and the foam collapses.

FOOD OF THE GODS

Lately, many of the better food stores have been carrying a wide assortment of chocolate bars from different countries. Some of my friends are comparing and discussing their merits as if they were wines. Mostly, they talk about “percents,” but percents of what? Also, I find the ingredient lists on the wrappers to be confusing. Can you help me sort these things out so I can be as snobbish as my friends?

Americans seem to have discovered only a few years ago that “chocolate” doesn’t have to mean Hershey bars and Whitman Samplers; they learned that serious chocolate bars, as distinguished from candy bars, could open a whole new world of flavors. There are now dozens of dark chocolate bars on the market from both American and foreign manufacturers. Among foodies, chocolate tastings threaten to replace wine tastings as entertaining and educational activities.

The ingredient lists on the wrappers can indeed be perplexing, because most of the ingredients go by a number of aliases. So let’s look closely at what is in a serious bar of dark chocolate.

It all starts with cacao (ka-KAH-oh), not cocoa (KO-ko), beans. Cacao beans are the seeds of the fruit of the tropical tree Theobroma cacao . ( Theobroma literally means “food of the gods,” a name obviously chosen by a chocophile taxonomist.) The bitter cacao bean was enjoyed as a spice by the Mayans and Aztecs, but only after it made its way to Europe was it sweetened with sugar.

The percentage number on a bar’s wrapper is the percentage of the bar’s weight that actually came from the cacao bean. That is, it’s the bar’s content of honest-to-goodness cacao bean components. Natural cacao beans contain 54 percent fat by weight; the other 46 percent is hard, solid vegetable matter. Thus, the percentage number on the wrapper of a chocolate bar is the sum of its cacao fat (called cocoa butter in the United States) and its cacao solids.