A PHOSPHORIC FUSS
I just read about a medical study indicating that teenage girls who drink a lot of soda have weaker bones than girls who don’t drink soda. According to the article, the researchers speculate that it might be an effect of “the phosphorus in carbonated drinks.” What is there about carbonation that involves phosphorus?
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othing whatsoever. The article shouldn’t have generalized to that extent.It’s a mistaken notion that all carbonated soft drinks are rich in the chemical element phosphorus (which almost everyone, it seems, wants to misspell as “phosphorous”). The only thing that all carbonated soft drinks have in common is carbonated water: carbon dioxide dissolved in water. Beyond that, they contain a wide variety of flavorings and other ingredients.
A few of them, including Coca-Cola, Pepsi-Cola, and some other colas (sodas containing the caffeine-rich extract of tropical kola nuts) do contain phosphoric acid. It’s a weak acid of phosphorus, just as the carbonated water itself is a weak acid of carbon: carbonic acid. All acids taste sour, and the phosphoric acid is there to increase the acidity and provide a bit more of a tang to set off the sweetness. Phosphoric acid is also used to acidify and flavor baked goods, candies, and processed cheeses.
About the bone-weakening effect: Maybe the study was limited to phosphorus-containing colas. Even so, just as one rose does not a summer make, neither does one study prove a cause-and-effect relationship between Cokes and bones.
THE BIG TANG THEORY
I have read that using powdered Tang in an empty dishwasher cycle will clean out all the soap scum and stains. I’ve also read that Coca-Cola will remove rust from a tennis net crank. What on
Earth have we been drinking?
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don’t know what you’ve been drinking, but there are plenty of riskier beverages out there than Tang and Coke. I’d be concerned about this particular duo only if my stomach were made of soapscum or rust. Just because a chemical does something to one substance doesn’t mean it’ll do the same thing to another substance. That’s what keeps chemists so busy.
It is undoubtedly the citric acid in Tang, Gatorade, and other fruit drinks that dissolves the calcium salts in dishwasher grunge. But it’s also citric acid that gives us that nice, tart…well, tang.
Citric acid is, of course, a perfectly natural and harmless component of citrus fruits. You could probably clean your dishwasher as well by running it on lemonade.
The phosphoric acid in Coca-Cola can dissolve iron oxide (rust). There’s nothing special about tennis net cranks, however, except that their rust films are likely to be rather thin because of frequent use. I wouldn’t try to rejuvenate a rusty old lawn mower by throwing it into a vat of Coca-Cola.
A BURP IN THE BUCKET
Does belching contribute to global warming?
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on’t laugh. That’s a good question. So good, in fact, that I thought of it myself when I learned that 15.2 billion gallons of carbonated soft drinks and 6.2 billion gallons of beer were consumed in 1999 in the United States. And what do you suppose happened to all the carbon dioxide in those beverages? It was ultimately released into the atmosphere by respiration and eructation—breathing and belching, to be plain-spoken about it.
On the traditional back of an envelope (scientists collect old envelopes for this purpose), I quickly calculated that 21.4 billion gallons of American beer and soda would contain about 800,000 tons of carbon dioxide. Wow! I thought, that’s one helluva collective burp. And that’s not even considering the chorus of harmonizing eructations from around the globe.
Why worry about carbon dioxide? It’s one of the so-called greenhouse gases that are acknowledged to be raising Earth’s average temperature. Granted, it hasn’t been easy to take the temperature of a planet. But modern scientific analyses are infinitely more sophisticated than stationing people on street corners with thermometers. Today, there is very little doubt that carbon dioxide and other gases produced by human activities have indeed been inching up the global thermostat.
Here’s how the greenhouse effect works:
There is a natural balance of energy between the radiations that shine upon Earth from the sun and those that are reradiated back out to space. When sunlight hits Earth’s surface, about two-thirds of it is absorbed by the clouds, the land, the sea, and George Hamilton. Much of this absorbed energy is converted—degraded in energy—to infrared radiation, often called heat waves. Normally, a significant fraction of these heat waves bounce back out through the atmosphere and return to space. But if there happens to be an unnatural amount of infrared-absorbing gas in the atmosphere—and carbon dioxide is a prodigious absorber of infrared waves
—then some of the waves will never get out; they’ll be trapped near Earth’s surface and warm things up.
So should we all stop drinking soda and beer for fear of belching more carbon dioxide into the atmosphere? Luckily, no.
According to the Department of Energy’s figures for 1999, the last figures available at this writing, 800,000 tons of beverage-inspired carbon dioxide emissions amounts to 0.04 percent of the amount of carbon dioxide that was belched into the American atmosphere by gasoline-and diesel-burning vehicles. Our guzzling of carbonated beverages, then, is a mere burp in the bucket compared with our guzzling of gasoline.
So by all means keep on drinking. But don’t drive.
SLOW LEAK
My frugal sister-in-law buys her soda pop in large quantities at a discount warehouse club, and she claims that it’s often flat when she opens it. Can a bottle of soda go flat if it’s never been
opened?
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y first reaction was no, not if there isn’t a slow leak somewhere in the bottle’s seal. But after extensive research, which consisted of dialing the 800 Consumer Information number on a Coca-Cola label, I find that it is not only possible, it’s quite common.After prompting the nice woman who answered the phone to enter the appropriate words into her computer, I eventually learned that plastic pop bottles (they’re made of polyethylene terephthalate or PET) are slightly permeable to carbon dioxide gas and that over time, enough gas can diffuse out through the walls to diminish the effervescence. That’s partly why—again to my surprise—many plastic soda bottles bear “drink by” dates on their caps. Glass bottles, of course, aren’t porous at all.
Classic Coke in plastic bottles, the woman said, has a recommended shelf life of nine months for optimum flavor and quality, whereas Diet Coke’s recommended shelf life is only three months. Why? “Try plugging ‘aspartame’ into your computer,” I suggested, whereupon after a few blind alleys we both discovered that the artificial sweetener aspartame is somewhat unstable and loses its sweetness over time.
By now we were having lots of fun with her computer, so I probed some more about what might affect the beverage’s quality. Freezing, the computer informed us, can lower the fizziness.
That one was a challenge for me to figure out, but this is what I think may happen: When the bottle freezes, the expanding ice can bulge out the bottle, and when it thaws the bottle may retain its expanded shape. That makes more gas space into which more carbon dioxide can escape from the liquid, lowering its effervescence level.
The moral of the story is always to check the “drink by” dates on your plastic pop bottles. A visit to my supermarket showed that Coke and Pepsi products are dated, but many other brands aren’t, except in the form of unintelligible codes. Store them all in a cool place—heat deteriorates the flavor—and chill thoroughly before opening.
And, yes, if your sister-in-law’s purveyors aren’t careful about how they handle the soda during distribution, or if it has been on their shelves, or hers, for years, it’s quite possible that when opened it will be as flat as her budget.
HOW TO FIX A FLAT
What’s the best way to keep soda pop from going flat?
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f you can’t finish the whole bottle and you want to keep the leftovers gassy and sassy until the next pizza, just stopper it tightly and keep it cold. You knew that. But why?The objective is to keep all of the remaining carbon dioxide in the bottle, because it’s the carbon dioxide, bursting its tiny bubbles on our tongues, that gives us that nice tingly sensation.
Also, carbon dioxide dissolved in water makes a sour acid: carbonic acid, which provides tartness. A tight stopper, obviously, keeps the gas from escaping. But the necessity of keeping the soda cold may not be so obvious.
For reasons that are better covered in Chemistry 101 than in Food 101, the colder a liquid is, the more carbon dioxide (or any other gas) it can absorb and hold. Your soda, for example, can hold about twice as much carbon dioxide at refrigerator temperature as at room temperature.
That’s why there’s a big blast of escaping gas when you open a can of warm soda or beer:
There’s a lot more gas in there than can stay dissolved in the warm liquid.
Now how about those pump-up fizz retainers that are sold in supermarkets and discount stores? You know, the ones that work like a miniature bicycle pump. You screw the thing onto your partially depleted two-liter soda bottle, pump the piston a few times, and put it away in the fridge. The next time you open the bottle, you’re treated to the biggest, most satisfying whoosh!
you ever heard, and you’re supposed to think, Hallelujah! My soda is born again!
But guess what? There isn’t one bit more carbon dioxide in there than if you had simply screwed the cap on tight. What you’ve pumped into the bottle is air, not carbon dioxide, and air molecules are totally irrelevant to the behavior of carbon dioxide molecules. (Techspeak: It is solely the partial pressure of CO2 that determines its solubility.)
That pump-up gizmo is nothing but a fancy stopper. Save your money.