Twinkie, Deconstructed (29 page)

Plaster is made by cooking gypsum just right. Heating it ever so gently removes about three-fourths of the gypsum’s natural water so that it absorbs water eagerly when mixed on a construction site (some lime and silica are usually added by the manufacturers to delay setting or to add surface hardness). After this simple processing, gypsum wins the honor of being the only rock that can be crushed into a powder and then turned back into a rock just by adding water. That’s why you can make plaster out of it (but not Twinkies). The calcium sulfate used in food looks and feels like plaster, and, scarily, even solidifies when wet, but is not as strong (I know, I tried it in my office).

Calcium sulfate has a riveting history. Though plaster was used on the ancient Egyptian pyramids and Greek temples, it was the French who popularized it as plaster of Paris (duh). Paris sits on top of a major gypsum deposit, and old gypsum quarries exist beneath much of the city, including under the Notre Dame cathedral.

According to legend, Benjamin Franklin is responsible for the success of plaster of Paris as a soil amendment in the United States (it promotes aeration in clay soils). He was our first ambassador to France, and so admired its use while he was there that he brought some back here in 1785. An energetic promoter, he worked it into the soil on a prominent hillside in the form of letters reading,
THIS HAS BEEN PLASTERED
. When the clover growing over the enriched soil grew dramatically denser than the analphabetic clover around it, he had successfully introduced gypsum as “land plaster” to American farmers. (The strange thing is that ancient Greeks gardened with it, too, so it is not clear why Franklin’s coaxing seemed new to the Americans.) Imported from Paris at first, gypsum’s popularity was assured when deposits were found in abundance around the United States.

Plaster of Paris was always a popular wall finish, of course, but plaster is hard to use on walls without talent and time, a big problem for Americans. In the 1880s, a man named Augustine Sackett figured out how to dry a layer of plaster between two pieces of thick paper, inventing gypsum wallboard. It really took off on a national scale when his Sheetrock
^®
was featured at the 1933 Chicago World’s Fair. Now it seems that every wall is made of it. And the gypsum producers are glad to add cooking to calcium sulfate’s vast array of industrial uses. But for food, it must be pure.

T
WINKIES AND
T
OFU

Calcium sulfate wasn’t officially approved for food use in the States until January 1980. But we’re way behind the rest of the world in that way. Gypsum has been used in food for more than two thousand years, though not for Twinkies.

In China, gypsum was used during the Han dynasty for coagulating soy milk to make tofu; some say it may have been used to stiffen bread dough in King David’s Jerusalem. Flour that is low in calcium can produce soft, sticky dough that would frustrate any ancient or modern baker and would be a nightmare for the major bakeries with all their pumps and machines; that’s why calcium sulfate is found in most types of regular bread. (Commercial bakers need more of a flowing batter rather than a stiff, dry dough, so any stiffness is relative.) Added in minute percentages—never more than 1.3 percent by law—calcium sulfate is loosely categorized as a dough conditioner for baked goods, its most common food function. But that description is very limiting. Some suppliers have identified more than one hundred uses for calcium sulfate as a direct food additive. And it is as cheap as common salt.

The main thing calcium sulfate does sometimes is take up space. In Twinkies, it also acts as a filler, keeping the custom-mixed baking powder ingredients mixed evenly and preventing caking, which is what it does in Kraft
^®
Calumet
^®
Double-Acting Baking Powder (same as cornstarch does in other brands)—perhaps the only way calcium sulfate finds its way onto your kitchen shelf. In short, you don’t need it at home, and you can’t buy it at the store.

Calcium sulfate also acts as an economical nutrient, adding a considerable amount of calcium to foods like Wonder
^®
Bread (20 percent of your daily value) at a bargain price. Calcium sulfate may also be the reason Twinkies can claim to provide a percent daily value of calcium per cake, but only as a beneficial by-product of its more important function in the batter. It works as a nutrient in soy cheeses, feeds yeast, and balances the acidity in cakes. And calcium sulfate helps canned fruits and vegetables retain firmness and stay juicy by binding with natural pectin and increasing their water-holding capacity.

Beer brewers use calcium sulfate to raise pH, and to control proteins and starches to get a paler, smoother-tasting, more stable beer that lasts longer on the shelf. It clarifies brewing water, too, in case a brewer doesn’t have a pure Rocky Mountain spring to draw from. And it fills out pharmaceuticals, while supplying a little extra calcium to boot, even though it is not an active ingredient. The totally dry version, a filler favored by pill makers, is so white (with the inevitable brand name of Snow White
^®
, of course) that it is sometimes used to make cake icings whiter. Natural food stores allow calcium sulfate in their stocks when it is used as a moisture absorbent and filler in capsules of other nutritional supplements. On the industrial side, calcium sulfate is added to plastic coatings, adhesives, and grouts for extra strength and reduced shrinkage. Quikcrete
^®
, ready-mixed patching cement, even includes a good dose of the Snow White filler for a clean, professional finish.

Calcium sulfate is cheap and plentiful, odorless, nontoxic, and tasteless. It does a good job at just over 1 percent of a recipe. Even at these low doses, we somehow manage to consume an astounding twenty-eight pounds each over a lifetime. What’s amazing is how little we have to do to it in order to eat it. Unlike plaster of Paris, the calcium sulfate destined for food escapes the oven altogether. What you eat is basically what is dug out of the ground. It’s just easier to chew than solid rock because it’s been ground into a superfine white powder.

S
CRAPE AND
G
RIND

The gypsum at the Southard quarry is as pure as it comes: 98 to 99 percent (the food laws require 98 percent). Famous for its purity since George Southard staked his claim and opened it in the first few years of the twentieth century, Dave Hollingshead, the current quarry manager, keeps busy “knocking the tops off the hills,” as he puts it. After removing as much as seventy-five feet of hilltop made of brown surface soil and rocks (mostly shale) with earthmoving equipment, meticulous workers use mechanical brooms and scrapers to make the bright white rock clean of any soil. Now that USG is no longer blasting the stuff out of the ground with dynamite, and mines were phased out in the 1940s, Hollingshead’s crews carefully scrape four inches of the white rock at a pass into neat windrows with what look like road planers, giant vehicles with rotating sharp blades beneath their chassis. Superclean front-loaders scoop up fist-size chunks as well as smaller granules and dump them into clean trucks that carry them quickly over company-built roads to the nearby mill for crushing. Any impure rock can be made into wallboard, but pure calcium sulfate makes superior plaster.

There’s enough pure calcium sulfate here to last until about 2030. The mine pits are usually the size of a few football fields and scattered over seven thousand acres, an area roughly ten miles long and a couple miles wide. Mounds of white rock surround the crushing plant, an agglomeration of mostly low-slung, steel buildings connected by a half dozen hundred-foot-long, elevated, angled conveyors. Against the earth tones of its surroundings, the bright white rock contrasts nicely. Here the chunks are reduced to the size of sugar or salt crystals in circular crushers called Raymond mills, thick rings of cast iron with interior rollers that fling themselves constantly against the inside. The particles are then screened, milled repeatedly, fine-screened, passed over by magnets, and finally air-separated from plain rocks and other debris to make a fine powder that behaves like well-sifted flour, which is essential, since much of it is premixed with flour for baking. As if this were some kind of rite of passage, only after the gypsum is ground can it be called by its food-grade name, terra alba, Latin for “white earth.”

The calcium sulfate destined for use as a filler, whether for food, pharmaceuticals, or paint, is an even finer powder that is calcined, or dried, to the point of complete dehydration, accomplished by passing it through a continuous oven. (Plaster was made for decades in a much more dramatic way by “boiling” the rock powder in a series of ten-foot-high and wide kettles to the point where you could literally see steam coming out.) Each batch of calcium sulfate processed for food use is measured by atomic absorption analysis, tested and certified for purity before being bagged or loaded into a truck or railcar and sent off to the bakeries. Like so many Twinkies ingredients, both grades are kosher. All of the steps taken with food-grade calcium sulfate are simple and limited to mechanical processes so that calcium sulfate earns a “natural” label from the folks in Washington who examine such things. Then again, it’s just a rock.

Simple, useful, inexpensive. Ben Franklin would have loved it (“A penny saved is a penny earned”), although it is not clear if he would have loved Twinkies. And he never could have imagined making a preservative like sorbic acid from petroleum, definitely not.

CHAPTER 24

Sorbic Acid

T
winkies, so fabled for their longevity, in fact contain only one preservative: sorbic acid.

All those myths about Twinkies having an infinite shelf life and being made solely of chemicals are not only wrong, but way, way off. Sure, the chemicals contained in many of the prior ingredients give it a longer shelf life, but they don’t actually preserve Twinkies—they mostly retain moisture, prolong softness, fight staling, and replace expensive, spoilable, naturally moist ingredients like butter, milk, and eggs. But cakes still need perfectly airtight plastic wrappers to stay “fresh” (remove the wrapper and the Twinkie is toast, turning hard as rock in no time). Sorbic acid doesn’t help with any of those things.

The most persnickety enemy of anything moist is mold, and the best thing around to fight mold is sorbic acid. What’s very, very reassuring is that sorbic acid is undramatically, boringly safe—so safe, it actually qualifies as a food itself. The only worrisome thing about it? How it is made—and that, it turns out, is a far cry from food processing.

O
IL AND
V
INEGAR

I had visions of locating the people who harvest some kind of berries to extract sorbic acid from, but, unsurprisingly, no one makes it from natural sources anymore. If you want to keep mold off Twinkies, you’d do a lot better with organic chemistry than a bunch of berries. Despite actually being a food, sorbic acid is made from petroleum. Nutrinova in Frankfurt, Germany, Daicel Chemical Industries in Arai, Japan, and Nantong Acetic Acid Chemical Co. in the Yangtze River valley of China—the only major makers of sorbic acid—make it from natural gas they import from Russia or Norway, the Asian Pacific, or China, respectively. Clearly this is not a local chemical. Not one berry is harmed in the making of these cakes.

I could say that sorbic acid is made from crotanaldehyde (let’s call it C) and diketene (let’s call it D), but that wouldn’t be doing you any favors. Neither one is a familiar chemical. Creating sorbic acid is complicated, which is probably why each company’s recipe is confidential and visitors are not welcome despite earnest and persistent efforts. Major chemical plants and oil refineries are not commonly open to scrutiny. But the science is out there if you dig deep enough.

The two main ingredients start with natural gas, cracked to make ethane gas (for C) and methane gas (for D). The ethane then becomes ethylene oxide, the same as is used for polysorbate 60. With the help of palladium, a rare form of platinum, this gas becomes C, a clear, stinky, and flammable liquid.

At the same time, the methane transforms into methanol (wood alcohol) with a little help from carbon monoxide. (Yes,
that
carbon monoxide! But don’t worry—it is not an ingredient, just a convenient source of chemicals that become part of a complex reaction…the same way it is used to keep your supermarket ground beef looking fresh. You did know that, didn’t you?) That methanol is then reacted again with more carbon monoxide to make acetic acid (no, it doesn’t come from wine), which itself is “cracked” at 1,300°F to make ketene, a flammable, toxic gas used to make aspirin (go figure), and which is quickly turned into D, a colorless or light yellow and, for once, stable liquid.

When both subingredients C and D are ready, they are mixed with a manganese catalyst (another rare metal—mostly used in steelmaking but also in gasoline mixtures to reduce knocking) to make sugarlike crystals. In China, workers donning lab coats and surgical hats control the processing in twenty-foot-high, bright blue, cylindrical, pressurized vessels from which pipes carry the crystals to tall stainless steel holding tanks that resemble those that you might find in your local microbrewery. They grind the crystals into a fine powder for bakeries and pack them in small, fifty-pound boxes—nothing larger is needed because sorbic acid is so potent. (At this point some caustic potash, potassium hydroxide, or calcium might be mixed in to turn the crystals into the water-soluble, salt versions, potassium sorbate or calcium sorbate—the sister products found in drinks, cheese, and sauces.) Though the whole process definitely does not suggest food, these crystals turns out to be the very benign sorbic acid, harmless and ready to eat.