~If a book has anything to do with food and wine, it’s likely to wind up on my sagging bookshelves. A couple of years ago I added to the shelves, What Einstein Told His Cook, by Robert L. Wolke. I loved the book for its explanation of science in the kitchen. One example among many of what I learned from the book had to do with the fastest way to defrost meats, sans the microwave.
~I am not a Luddite, but in the kitchen I don’t use a microwave—don’t even own one, and don’t feel I need one. But with my penchant for deciding late on what to have for dinner, defrosting meat without a microwave has always caused, shall we say, a discussion at home. Wolke gave me the answer: stainless steel.
~Stainless steel is a good conductor of temperature, so when frozen meat is placed in a stainless steel vessel and rested in the kitchen, the stainless steel conducts the room temperature so that the meat defrosts faster than it would if resting on any other surface. A lesson learned.
~Still, as much as I like Wolke's book, something in it made me want to scream.
~The book doesn’t cover wine much, but Wolke made a passing reference to the wine headache that is caused by sulfites. Unlike all other scientific statements that he made in the book, he left this “fact” about sulfites hanging without explanation.
~I sent Mr. Wolke an email, asking that he please direct me to the science behind the sulfite-induced wine headache. He answered that he had no scientific evidence for his comment. In fact, he said that he had heard of the phenomenon and was just passing the information along.
~I was floored by the fact that the tenacious sulfite wine headache myth is so lodged that even an otherwise thorough scientist would accept it as truth. I sent him a second, raving, email, but he chose—wisely— not to respond to it.
~In prehistoric times—the middle nineteen eighties—restaurants across the country went absolutely crazy over the salad bar concept. But salad is a difficult thing to leave out all day in a large pit, under lights (it's also an ugly thing in a restaurant, but that subject is for someone else’s blog). Left hanging around, the green stuff in salad turns brown, the colored vegetables pale, and all of the vegetables wilt. The browning and wilting is caused by oxygen, the same culprit that makes us shrivel when we hang around too long and get old.
~Restaurateurs made use of a substance that keeps browning, wilting and an early demise at bay, at least in vegetables. The substance is made up of one part sulfur and two parts oxygen (SO2), and it is a gas. Ironically, SO2 gas is largely the result of decaying vegetation.
~Restaurants used a powdered form of SO2, which was sprinkled on the vegetables to keep them looking fresh. Unfortunately, airborne SO2 can shut down the respiratory system of asthmatics. More unfortunately, restaurant use of SO2 was unregulated, so the stuff was over-sprinkled and sure enough a few asthmatics suffered serious reactions (I believe a couple of them may have died).
~The federal government banned the use of SO2 in salad bars, which some of us considered no real loss—I refer to the salad bars, of course. But while this SO2 problem erupted, interest groups with names like the Center for Science in the Public ~Interest took notice.
~Around the time of the salad bar incident lobbying groups were pressuring the federal government into slapping the GOVERNMENT WARNING on wine labels (that regulation is just short of two-dozen years old). The interest groups knew that SO2 was being used to protect wine from early oxidation, and since they already had helped to predispose the government to warning labels on wine, they jumped at what they saw as an opportunity. When they couldn’t get the government to ban its use in wine production, a move that would have set the wine industry back about 1,800 years, to the first time SO2 was used in the Roman wine industry, special interest groups pressed for a separate warning label: CONTAINS SULFITES.
~The main problem with the sulfite warning on the wine label is that it doesn't provide much in the way of information. The warning says nothing about quantity, you know, like, how much SO2 does the wine contain? More important, wine is not alone: bread, cheese, yogurt, and just about every packaged baked food also contain sulfites. Call me a nitpicker, but if the government is going to warn me I’d like the warning to have meaning (in a later post I shall take on the overarching GOVERNMENT WARNING, which truly is a waste of font).
~I digress. Anything that ferments produces sulfites as a by-product, and that includes your stomach as it digests food. So we all experience sulfites in our systems. Wine is of course a fermented product but the natural by-product levels of SO2 left behind are not high enough to keep oxidation at bay, so winemakers add SO2—usually as a gas—to increase its effectiveness, and they do so under strict government regulations, and yes, almost every wine produced contains sulfites in some level. To be sure, asthmatics respond negatively to sulfites but they don’t all respond in the same manner or to the same level of SO2—estimates in the United States are that about .02% of the adult population may react negatively to sulfites and not all of them are known wine consumers. Generally, the regulated levels of SO2 in wine pose little threat to the majority of consumers. Further, the SO2 levels in wine are usually lower than they are in packaged baked goods; you know, the foods without the sulfite warning.
~So what exactly did the sulfite warning accomplish? Not much for the consumers but a little for the special interest groups.
~First, confusion over the issue, plus the fact that the sulfite warning doesn’t tell us anything, gave the impression that wine producers started to add SO2 to wine in the middle of the nineteen eighties. Again, 1,800 years ago in Rome and ever since; need I say more? (For those under the other illusion created by confusion, that Europeans don't add sulfites in Europe; they do, they just haven't had to warn their customers at home, but they had to warn us when they exported wine to the U.S.)
~Second, after the sulfite label was affixed, almost overnight American consumers started to get headaches from the SO2 in wine.
~I’d call those two events a parley for special interests.
~The people who claim headaches from the sulfites in wine don’t often talk about the headaches they experience after eating bread, cheese, yogurt or those SO2-loaded packaged baked goods. The reason: the sulfites in wine do not cause the headaches, at least not according to the science. To date, after numerous studies, no serious scientific evidence supports the sulfite-induced wine headache phenomenon. It is a die-hard myth.
~Ruling out a hangover, real science (as opposed to special interest science) has yet to offer a definitive cause for the wine headache. The latest information points to substances known as biogenic amines. Histamine is one of many biogenic amines that can be found in wine. Coincidentally, a lot of people who say that wine gives them a headache take an antihistamine before consuming wine and they say that it works—imagine that!
~Finally, a note to asthmatics, if you stick your nose into a glass of wine and you get a heady whiff that reminds you of matchstick flint, there may be too much SO2 in the wine. But if you are at that point, it may be too late—you should have read the sulfite warning. Wait a minute, that won’t work either: the warning tells us only what we already knew.
For more information try these links: Anorak, SO2, SO2(B), Biogenic
Copyright December, 2006
All rights reserved, Thomas Pellechia