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How Wine Sulfites Became the 'Bad Guy'

Less than 1 percent of the U.S. suffers from sulfite sensitivity—so why does “Contains Sulfites” trigger so much fear?

Interest in more naturally made wines—whether they’re organic, biodynamic, or brandish neither certification—is growing alongside a general consumer shift towards foods that contain fewer artificial, processed ingredients. But when imbibers flip over a wine bottle for more information on what’s inside, they don’t find an ingredient list or a nutrition label.

Instead, the tag "Contains Sulfites," jumps out menacingly.

And while most people don’t know exactly what the phrase means, the warning has created a perception that sulfites must be harmful and should be avoided.

"People are starting to ask questions [about what’s in their wine], and that’s good," says Gilian Handelman, director of education at Santa Rosa, California's Jackson Family Wines. The question is: Are they asking the right ones about sulfites—in terms of their purpose, how wines may be different without them, and the truth about potential health risks?

What Are Sulfites?

Sulfites are compounds that occur naturally in some foods and wine, but they're also added as preservatives (and often interchangeably referred to as sulfur and SO2 when discussing winemaking). Recently, sulfites have garnered more attention as natural winemaking—which generally refers to wines that are made from organic or biodynamically grown grapes, with very little alteration (nothing added, nothing taken away)—has become increasingly popular. But "natural wine" is ultimately a term that carries no formal definition. So, while many such winemakers do not add sulfur to their juice, others do add small amounts, further increasing consumer confusion.

"There is a humongous interest in wines made without sulfites," says Roberto Paris, wine director at Manhattan’s Il Buco, an Italian restaurant whose wine list is comprised of about 20 percent no-added-sulfur wine. "It’s very hard to be ready for it."

Sulfite-free wine does not truly exist.

Especially since sulfite-free wine does not truly exist. Grape juice becomes wine through fermentation, which occurs when yeasts convert sugar from the grapes into alcohol. "All yeasts will produce detectable amounts of SO2," explains Gavin Sacks, a professor and researcher at Cornell University’s Viticulture and Enology program.

Naturally occurring sulfur, however, exists in very small amounts. USDA-certified organic wines, for example, can include up to 10 ppm (parts per million) and are not required to carry a sulfite warning. The "Contains Sulfites" label must be added to a bottle that contains above that amount (and up to 350 ppm in the U.S.), due to sulfur that is added at various points during the winemaking process, primarily right before bottling, but also sometimes to the grapes during pre-fermentation or post-fermentation.

In terms of wine, sulfur provides two important functions, Sacks explains. The compound acts as an antimicrobial to prevent the growth of yeast or bacteria, and also prevents oxidative spoilage—when a wine is exposed to too much oxygen (for example, during bottling, or due to a faulty seal) and, in turn, loses its color, and takes on a sour, vinegar-esque flavor.

Sulfite Sensitivities

Winemakers have been using sulfur for several centuries. Most current health concerns related to added sulfites stem from the fact that a small percentage of the population—estimated at less than one percent in the U.S., most of whom are asthmatics—have a sulfite sensitivity, which can cause serious reactions similar to that of an allergy, from skin to digestive to respiratory issues. Most experts say that risk of reaction does not exist for the rest of the population, and while there hasn’t been much recent research on the topic, the most comprehensive studies done in past decades that looked at possible sulfur-related health risks have found them to be safe. While some imbibers also believe sulfur is linked to headaches, there is no scientific evidence to support that claim, either.

"Sulfites may cause an allergic reaction (oftentimes similar to hay fever), but the evidence just doesn't support the theory that they cause 'wine headaches,'" says Amy Shapiro, RD, founder of Real Nutrition NYC, or that they’re harmful to longterm health. "Instead, wine is an inflammatory substance when consumed and has the potential to trigger the release of histamines, which can cause headaches." Sacks agrees: "It’s easier to focus on the trace level things that sound unfamiliar. The most dangerous thing in the wine, by far, is the alcohol."

Why Some Winemakers Pass on Sulfur

There are plenty of reasons to skip or minimize the use of sulfur, though, that have less to do with health concerns and more to do with the craft of winemaking and the quality of the final product. "When you work in a proper way using organic or biodynamic means, with healthy lands and proper vinification, the wines will show well and not need the use of sulfur," explains Jorge Riera, wine director at Manhattan’s Contra and Wildair restaurants, where only natural wines are on the menu. "It's something that people began to use in a heavy handed way for mass consumption and to control. Natural wines embrace the old methods, which are wines that are unaltered from vine to bottle and not manipulated."

There is no scientific evidence that links sulfur with headaches.

Paris adds that unsulfured wines can be more interesting, expressive, and complex. "The wines are more or less free to do what they can do by themselves. You can recognize not only the wine and the grape, but the single origin of the wine. The terroir is more relevant."

The challenge is that winemakers have to think about how to alternately manage both the antimicrobial and antioxidant functions of sulfur, explains Sacks. "They have to be considered individually," he says, and so far, no perfect substitutes that don’t cause changes in flavor exist for either. Instead, winemakers that add little or zero sulfur try to minimize the risks of spoilage and oxidation with strategies like filtration to remove bacteria, using packaging that allows in minimal oxygen (screw caps are the best for this, Sacks says, while low-quality synthetic corks are the worst), or making wines that lend themselves more to the method, like reds, which contain natural antioxidants from the grapes themselves and can therefore help resist oxidation.

Handelman also says that scale is more challenging without sulfur. "We own our own vineyards and can control how we farm, so we’re able to use a lot less sulfur," she states, but shipping in large quantities makes eliminating it altogether nearly impossible, since sulfur preserves wine that could be damaged by shipping conditions, like heat. "You can do it, absolutely. But would you make a 20,000-case wine without sulfur? Hell no, because you’re shipping it all over the place."

Restaurants and Unsulfured Wines

Wine directors and sommeliers can end up on the receiving end of that issue, where they say that a higher percentage of no-sulfite-added bottles end up being sent back by diners, either because they’ve truly gone bad, or because the drinkers’ palates are not used to the complexity. "You can have a mainstream barbera that’s easy to drink, and then one without sulfites that’s full of funkiness—and people think it’s off," explains Paris, who says it’s been tricky to train the waitstaff at Il Buco to be able to recognize the nuances, even as he’s actively added natural wines to his renowned, unique wine list to meet demand.

"The most dangerous thing in the wine, by far, is the alcohol."

Riera says if unsulfured wines are well-made, though, they shouldn’t have too much funk on them, but he does admit there can be a learning curve. "They smell like good, well-made wines. They’re reflective of the life in the grapes and the earth they're from, but also many people are not used to smelling the life of the earth and the grape. For the non-experts, it's just a matter of learning and tasting, and having more exposure to these wines."

Other Wine Additives

And sulfites are not the only aspect of natural winemaking people should consider, Paris adds, referring to other additives and shortcuts used by cheap, bulk producers, like added sugar and chemical herbicides such as glyphosate (AKA "Roundup") that have been linked to very serious health concerns and are used widely in agriculture, including vineyard maintenance. Levels of glyphosate were recently found in several California wines (in a small group of bottles tested by an advocacy group, not an independent scientific study).

"We know that even the best wineries that make wines with mainstream systems, as we’re speaking now, they may be spraying the vines," he says. "That’s something that natural winemakers wouldn’t do." So while sulfur is often the villain, embracing natural wine—both for your health and palate—and getting to know individual producers’ overall winemaking ethos, is perhaps paramount to worrying about a sulfite label.

We have the right to know what we’re putting in our bodies, like in everything else, but wine bottles don’t have any sign. All they says is "Contains Sulfites."

Editor: Kat Odell

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