Over the years, sulfites have become an antagonist in the world of wine: from headaches to hangovers, the preservative compound has taken the blame for a wide range of bodily ailments. But are they really the enemy? To evaluate the merits of these anxieties, it’s best first to ask: what are sulfites, exactly, and how do they end up in the wine we drink?
Know Thy Enemy
First off, sulfites are not exclusive to wine. You find them in a wide range of other foods and beverages, including pickles, cured meat, fruit juices, and chocolate. The term refers to chemical compounds that contain sulfur ions, which are antimicrobial agents that work as a preservative against certain yeasts and bacteria.
Don’t let the scientific terminology throw you off. Before you begin imagining sterile laboratory set-ups, know that sulfites aren’t always synthetically added. They can also occur naturally as a by-product of fermentation (which is why sulfite-free wine is virtually non-existent).
Wine can be placed in both the former and the latter categories. During fermentation, yeast—which can be either naturally-occurring or added in the form of the commercial bakers’ variety—eats the sugar in the grape juice and converts it into alcohol. This process produces sulfites that slow the oxidation process and ward off bacteria that can make a wine discolored or taste vinegary. If the bacteria fights back, a winemaker can add powdered sulfites to give the yeast extra oomph.
Although it’s normal to be wary of additives associated with industrial food production, the practice of adding sulfites to wine dates back millennia. The ancient Greeks recognized that adding powdered gypsum—a white, sulfur-rich mineral—to their wine before fermentation increased its longevity. To the same end, the Romans burned sulfur candles inside their clay vats prior to adding the treasured liquid.
So, Are Sulfites Bad for You?
Pick up any bottle of wine and you’ll likely see a blocky font alerting you to sulfites. This provision appears like a warning sign and has contributed to the widespread idea that sulfites cause wine headaches, among other maladies. Why else would producers be required to label their presence explicitly?
The answer goes back several decades, to the early 1980s when the U.S. Food and Drug Administration (FDA) became increasingly aware of sulfite allergies. To protect persons with these sensitivities, the federal agency mandated the “Contains Sulfites” label in the same way peanuts are clearly marked on most food packaging.
We now know that just 1 percent of the U.S. population has sulfite allergies. So, if you eat shrimp, cheese, canned soups, and lemon juice—the list goes on and on—without adverse reactions, your allergy symptoms are very unlikely tied to the sulfites listed on the bottles. A serving of dried fruits, for instance, may contain up to 2,000 ppm of sodium dioxide per serving, while french fries contain 1900 ppm. The legal limit for a bottle of wine, on the other hand, is 350 ppm, and the average bottle contains just 125ppm.
Much ink has been spilled over the past few years debating whether added sulfites are good or bad for human health. Now that studies have widely established that added sulfites impact only a tiny portion of the population, the question we should really be asking is: Are sulfites good or bad for wine? Predictably, industry experts remain divided on this question; the answer depends on what you value in your bottle.
In general, the lower the acidity of the wine, the fewer sulfites it will contain. Likewise, wines of a stronger hue (reds) generally need less added sulfites than their clear counterparts (whites). Meanwhile, since sulfites stabilize fermentation (sugar is a necessary catalyst), sweeter wine tends to require the most sulfites. By this logic, sweet dessert wines contain the highest levels of sulfur dioxide, followed by blush-tone and semi-sweet white wines. Dry reds are found on the other end of the spectrum, just below dry whites.
Since natural fermentation produces remarkably few sulfites—anywhere from 5 ppm to 40ppm—low-interventionist production philosophies generally place biodynamic, organic and natural wines on their own separate sulfite spectrum. Why?
Although sulfites do not have negative health consequences, they can change a wine’s long-term chemical profile. That is, at a molecular level, the extra sulfur dioxide impacts how various compounds combine. New research is beginning to explore how the oxidation process takes place at different paces in wines with added sulfites and wines without, producing different aromas, mouthfeels, structures, and aging qualities.
In short, sulfites are powerful sterilizers that kill off bacteria and unwanted yeast, simplifying the winemaking process and yielding a final product that is more predictable and reliable. This type of consistency is especially desirable for mass production and is also crucial to the identity of many commercial brands.
In this sense, it takes expertise and depth of knowledge to produce quality wine with minimal or no added sulfites. Wine enthusiasts who delight in broader and more interesting flavor profiles will often seek out natural, organic, and biodynamic wine for this reason. Not because they’re healthier (to be clear, they are), but because these wines, like good art, bear the distinctive stamp of a maker’s hand.
Curious to learn more about natural wine? Save your spot in VIVANT’s Organic & Biodynamic Experience.