Twinkie, Deconstructed (21 page)

The newly mined limestone, calcium carbonate in its crude form (exactly what Tums
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are made of ), comes out in pieces as big as cars. It is crushed to football-size chunks in giant presses and carted in train cars up to the tops of nine tower ovens, some as much as eighty feet tall, encircled by catwalks and crisscrossed by long, angled conveyors.

Once dumped inside the kilns, the calcium rock is heated up to more than 2,000°F in order to drive off the CO
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and transform the rock into calcium oxide (sometimes called lime, pebble quicklime, or just plain quicklime). The newer ovens produce as much as ten tons an hour. That’s a lot of lime. To get this kind of heat the full bottom third of some ovens is given over to pure flame. Fossil energy is a concern. After as little as two hours of baking, the resulting powdery “pebbles” of lime, now almost half their original mass, are crushed and screened for size. Rounded chunks one to two inches across are shipped off to places like the Chicago phosphate plant where they will meet up with the soda ash from Wyoming and the phosphoric acid from Idaho and Tennessee to be made into baking powder.

The pebble lime is loaded into sealed boxcars. It seems like overkill, enclosing mere rock like that, but precautions must be taken when you’re dealing with quicklime, which is highly reactive. Left in the open, a pebble can turn into dust in a week’s time. And there are other challenges inherent to quicklime: the lime companies learned a long time ago to keep the railcars absolutely dry. Apparently they first started shipping pebble lime in leaky, wooden freight cars. If it rained and the load got good and wet, the resulting chemical reaction generated enough heat to set the railcar on fire. New technologies always bring with them new challenges. Keeping your product from burning down the house, so to speak, is always a good place to start.

Ash for Twinkies

The third ingredient for Twinkies’ baking powder, soda ash, comes to Chicago from FMC’s Green River, Wyoming, trona mine and soda ash plant. After being conveyed about eight miles from the bottom of the trona mine previously described (both baking soda and soda ash come from trona), the ore is dropped onto piles the size of large houses at the Green River processing area. Bulldozers and front-loaders groan and roar as they push the piles into shape and back onto other conveyors up again and a half mile over to the soda ash plant. The conveyors look like sophisticated monorails, crossing fifty feet overhead, all bright white against the cobalt blue sky.

Boxy buildings house the mechanics for processing the trona, which is crushed, screened, boiled, clarified, filtered, dried, and cooked in a city-block-long, revolving tube of an oven; only then is it fine and pure enough (99.5 percent) to be called soda ash. As it cools down to different temperatures in a device called a crystallizer, it forms—what else?—crystals of different sizes, or eight grades, for hundreds of different end uses. They are colorless but reflect so much light that they appear bright white, like snowflakes. Today, it is one of the top ten inorganic chemicals produced in the United States, an essential ingredient in many industries including medical, oil-refining, and above all, glass-making. Sodium carbonate, aka soda ash, sal soda, or washing soda, has a long history of service to mankind.

For starters, prehistoric people were known to leach water through the ashes of burned plant stalks to obtain their primitive detergent for clothes washing, and the ancient Egyptians made glass ornaments with soda ash recovered from dried desert lakes. Green River soda use predates the mines: the Union Pacific Railroad tapped wells in the Green River, Wyoming, area for a crude, soda-based water softener for their steam engines in 1907. But glass-making has been its major use for centuries, and continues to this day. Soda ash, which is about 15 percent of the raw materials in glass, acts as a flux for the silica. About a quarter of the soda ash mined goes into container glass, and almost an equal amount into flat glass, fiberglass, and specialty glasses.

Still, another quarter of the soda ash processed goes into making other chemicals, often just to provide a base to balance off an acid, or as a reliable and not too expensive source of sodium. That is more or less what it does in Twinkies, where it is used to make chemical leavening. The other major use is, true to its ancient roots, for washing clothes—soda ash is also called washing soda, after all—and is a fundamental ingredient in many detergents as well as soaps and other cleaners, largely replacing the cruder and more expensive lye (the reason it is also used to digest wood pulp in the papermaking business). Interestingly, soda ash is also used to remove sulfur dioxide and hydrochloric acid from smokestacks by absorbing them in giant “scrubbers,” which is ironic, considering that a few centuries ago, soda ash manufacturers generated these same pollutants. Specialized uses include sandblasting, hemodialysis filters, acid buffering in pharmaceuticals, and, of course, food products such as those in leavening.

This soda ash plant can produce more than 100 million tons of virtually pure sodium carbonate each year. Outside, a line of clean, white, sealed 100-ton hopper cars wait to be filled with fresh powder (FMC owns about 1,800 of them). Some of the hopper cars go to Kansas City to be made into sodium stearoyl lactylate, but the ones we care about right now are headed to Chicago to provide the sodium for sodium acid pyrophosphate, the third ingredient in baking powder.

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ALTS
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On the industrial south side of Chicago, I am about to see how truckloads and trainloads of dangerous acid (phosphoric acid) and crushed rocks (lime and soda ash) become two similar, food-grade, bagged white powders, leavening agents ready to be baked into Twinkies or packaged into baking powder for the home cook: sodium acid pyrophosphate (SAPP) and monocalcium phosphate (MCP). The fact that the manufacture of these two ingredients is so similar is not surprising. Both contain phosphate from phosphoric acid, and both are salts made by reacting a base with an acid—in this case, soda ash with phosphoric acid for the sodium acid pyrophosphate; lime with phosphoric acid for the calcium phosphate. The engineers refer to the place as a “salts” plant.

There’s been a phosphate plant of some sort here since around 1900, but to say that there’s been a tremendous change in techniques and raw ingredients over the years is to put it way too mildly. The original source of calcium was cow and pig bones (and perhaps teeth) from the nearby legendary Chicago stock-yards. The bones were boiled in sulfuric acid, which smelled awful and created toxic waste. But this plant is clean, odorless, modern and well-organized. Plain, low-cost apartment houses in need of maintenance and even a small, ramshackle farm sit nearby, bringing an odd, worn-down, urban/rural balance to the factory’s industrial presence, what with its ten-story storage silos and chain-link fence gates.

Way in the back of the plant is a black, spherical tank filled with phosphoric acid: an acid-filled bowling ball the size of a house. The acid arrives in a constant chain of railroad tank cars lined up along the railroad siding, each holding more than 100 tons of the clear, oily, dangerous liquid. A massive array of pipes leads from this tank to the plant, a few hundred yards away. One set takes it to the part of the plant where the SAPP is made, another set to the MCP area.

Cyclone Activity

At a railroad offloading area on the far side of the plant, white soda ash hopper cars from Green River, Wyoming, are entering a covered area quietly, one at a time. Each railcar drops its load of sodium carbonate through a hole directly underneath it onto a basement conveyor, which dumps it into a five-thousand-gallon reacting kettle, along with a good dose of phosphoric acid. The resulting thick liquid, after passing through two different mixers, is cooked for an hour by spiraling through a thirty-foot-long, ten-foot-diameter, rotating oven that runs and rumbles twenty-four hours a day. The 450°F heat turns the liquid into crystals, simultaneously purifying it. A ceiling-high, funnel-shaped machine called a cyclone completes the drying and crystal-sorting process with a vigorous spin cycle.

The crystals are screened for various desired sizes, ranging from powder to saltlike. As with bicarb, crystal size is critical for each particular use. Of the dozen or so types, Donut Pyro
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is one of the most interesting, invoking images of an overweight arsonist. Donut Pyro is what you need for making doughnut batter fluff up while being deep-fried. Though “pyro” normally implies something to do with fire, here it is a chemical term that means “chain of two,” as in a single molecular chain formed from two separate phosphate molecules (phosphorus and oxygen) by the heat.

The plant is so automated that eerily, I see almost no one as we go dodging through a playground of augurs in stainless steel pipes. I finally spy a lone worker feeding empty bags to a robot that fills and stacks them on pallets, always remembering where it put the last bag and putting the next one neatly next to it, eight to a layer, ready for the bakeries. Dozens of similar products intended for industrial use fill a nearby warehouse, the route of one-third of baking powder.

Better Than Boiled Bones

Monocalcium phosphate, the other third of baking powder made here, starts at a second, covered rail dock, where hefty, sealed hopper cars full of loose, small, white-grayish, dusty rocks unload through their open bellies onto a subterranean conveyor belt. More rocks to eat. All the chunks are rounded and pockmarked. This is the limestone that has been processed into calcium oxide. The result is a nice, clean source of calcium, much more palatable than acid-boiled bones, and apparently much more efficient for baking powder than soybeans, sesame seeds, or milk. This mineral is so reactive that it seems almost alive. The pockmarks are the start of its reaction with the air. You can imagine it reacting with the acid.

With a low rumble, Innophos’s conveyor whisks the pebble lime chunks into the basement, where they are pulverized, conveyed straight up, and then sent as a lumpy liquid via screw augurs in big pipes straight into the looming, five-thousand-gallon, stainless steel, enclosed kettles, along with phosphoric acid that has been piped in from the acid tank in back. The chemical reaction is instant and vigorous, as the lime and phosphoric acid are both obviously highly reactive. We’re all wearing safety glasses and hard hats to protect ourselves from caustic or acid burns in case of an accident, and have removed all of our rings and watches not only as a security precaution but also because this is a food plant, despite its industrial feel, and there is zero tolerance for anything foreign that might tumble into the food containers.

Bucket and screw conveyors angle through the plant like so many flying attic rafters. But instead of being quiet as an attic, everything boinks and clanks and rumbles gently as the newly reacted chemicals are carried off to be dried in a room-size, rotating 250°F oven and packed into bags or “supersacks” (about a ton, filling out a big bag on a pallet) and shipped off to the cake-makers of the world.

Delicate powdered mixes made from phosphorus ore, sodium carbonate ore, and limestone, all dug from the ground, become an essential ingredient for baking light, fluffy cakes. It’s a massive operation involving humming elevators, conveyors, ovens, and trains, all in the name of Twinkies, and not one bit of it suggests food. They could just as easily be making cement here, as far as an uninformed visitor is concerned. And why not, considering some of the ingredients?

Standing outside the plant gate, the point is clear: We eat rocks. Lots of rocks. And I’m about to go see another rock on the ingredient list, salt, brought up from deep underground without budging from the surface myself.

CHAPTER 17

Salt

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here are three main ways to harvest salt, one of the several rocks we eat when we eat Twinkies. You can evaporate salt water to get crystals naturally—the oldest method—but that takes as much as two years of sunny, windy weather found only in limited (but beautiful) places. You can blast it out of a mine with dynamite and front-end loaders and then crush it, but that takes big mining operations and leaves a fairly impure rock salt suitable for water softening, ice control, and chemical processing—not food. Or you can flush it out of the ground with water and boil it down in an evaporation plant.

Only this last method, called solution mining, produces the fine, pure crystals of salt that we purchase at the grocery store or that are used in processed foods. Morton has a big facility devoted to this in the tiny, Victorian, one stop-sign town of Silver Springs, New York, near Rochester, that has been operating pretty much the same way since 1884. It is Morton’s oldest facility, and it is one of the reasons that the Erie Canal, “the ditch that salt built” as they say, is nearby.

The table salt processed here is actually pumped out of the ground as brine a few miles north, from various wells in the middle of a few fields, and sent by underground pipe to this facility. At this writing, the area is napped with a blanket of snow, providing a poignant contrast to Morton’s solar salt facility in the Bahamas, one, which I readily admit, I’d prefer to visit this time of year.

Morton’s plant is an agglomeration of nondescript industrial buildings, including a few that date from its Victorian days. The office building is gabled and brick (with a well-salted, ice-free walkway, of course) and some carved mahogany detail still surrounds a few of the older doors. The posts in a post-and-beam warehouse attached to the office look almost perforated with little slits. This is the former salt barrel–making loft, and for years, the barrel stave craftsmen tossed their axes into the posts as a quick way to hang them up. Pictures from 1911 featuring mustachioed and bowler-hatted workers line the current office walls, showing the perpetrators in action. This place reeks of history, and of course, salt has its own history—more ancient than Morton’s.