Grapes and yeast, sure. But what about Zyme-O-Clear, Gelaxina or mega purple? F&W explores the weird, wide-ranging world of wine additives—and asks what effect (if any) they have on taste.

What's Really in Wine?
Credit: © Michael Graydon & Nikole Herriott

Think back to the last bottle of wine you drank. What do you suppose went into making it? Easy, you might say. Grapes. And yeast. Possibly an oak barrel?

Good start. Keep going. You’re not even close.

Let’s say that bottle cost you less than 10 bucks and was pumped out by an industrial wine factory. Or maybe it set you back $100 and came from a boutique winery you visited in Sonoma. Either way, there’s a decent chance it was made with some combination of sulfur dioxide (to preserve it), gelatin (to remove mouth-puckering tannins), Velcorin (to kill microbes) and, if it was a red, the grape concentrate Mega Purple (to pump up flavor and color). Winemakers can use around 60 different products to remedy flaws and tease out flavors. But you, the drinker, have no way of knowing which ones might have gone into your glass. There’s no law requiring bottles to be labeled with these ingredients, and most winemakers oppose volunteering the information.

Generally, they’ll explain that this is for your own good. You might panic if you found out that your wine was dosed with a toxic-sounding chemical like tartaric acid—even though it’s an organic compound that occurs naturally in all grapes. What’s more, the reality of modern-day winemaking, with its labs and powders and pumps, doesn’t square with the romantic image of wine as an artisanal miracle. Thus, winemakers reason, it’s best not to talk about what really happens.

If you’re curious and like wine, you might draw a different conclusion: It’s precisely because of this disconnect that winemakers should open up about what’s gone into their tanks. Producers and sommeliers are fond of saying that wine is food. Yet unlike almost every other edible we consume, our Syrahs and Chardonnays are not bound to disclose what they’ve been made with, an oversight that seems especially glaring at a time when people have grown obsessed with everything from GMOs and gluten to the organic (or not) ingredients in their foods.

Black-box winemaking—where we see nothing that goes in or out—has not provoked any kind of real pushback. In 2007, California winemaker Randall Grahm began tweaking his labels to catalog everything he’d added, but only a handful of American producers followed suit (Shinn Estate Vineyards in New York and California’s Ridge Vineyards are two of them). Now, however, because of the following factors, it’s time to advocate for full disclosure: the spread of what UC Davis enology professor Anita Oberholster calls controlled winemaking, which relies heavily on additives; the rise of natural winemaking, which eschews any manipulation as evil; and the influence of the organic food movement.

My dive into the curious world of controlled winemaking was at a trade expo in Sacramento packed with 14,000 pros, as well as products with sci-fi names like Gelaxina and Zyme-O-Clear. Producers discussed “manufacturing” wines, rather than “making” them, as they perused jars of enzymes that would accent fruit aromas; vials of liquid grape tannins meant to mimic barrel-aging; bags of bentonite clay to remove haziness-causing proteins; and catalogs of designer yeast strains that promised to boost a Sauvignon Blanc’s notes of pineapple (or peach, bell pepper or lemon, depending on the winemaker’s preference). These adjuncts, as they’re known, are more likely to show up in high-volume wines to minimize errors and correct for subpar grapes. But a little outside assistance doesn’t automatically mean the wine is swill. “We work with customers who sell wines for $150 per bottle, and they use the same kind of products—or even more—as the winery that sells bottles for $10,” says José Santos, president and CEO of Enartis, a company that supplies winemaking products. Santos argues that a fine wine is impossible without some help: “If you want one that is drinkable, that is good for you and that has good sensory qualities, you need to control the process.” Additives have also improved the overall quality of bargain bottles. “Even though it’s not a sexy story,” admitted a salesman at the expo as he spritzed a mist of oak chip essence for me to smell, “additives are what make it possible for you to spend $6 to $12 and still get a nice glass of wine.”

Additives in wine are nothing new: The ancient Romans tried to make their wines more palatable by doctoring them, alarmingly, with everything from lead to marble dust. There’s no evidence that modern adjuncts ring similar alarm bells, though some are initially toxic, like Velcorin (an antimicrobial agent, it breaks down into carbon dioxide and water after 24 hours). Sulfur dioxide, a common wine preservative, is regularly blamed for causing headaches, though UC Davis professor Andrew Waterhouse notes that no research has teased out such a link, and even anecdotal evidence is shaky. (A handful of dried apricots contains about five times more sulfites than a glass of wine, and stores often add sulfur to vegetables to keep them from browning, yet “no one complains about the salad bar giving them a headache,” Oberholster quips.) Yet the chemistry-set names make most adjuncts taboo despite their widespread use, and winemakers are tight-lipped about using them.

Some producers (both proponents and critics) disagree about what role additives should play yet concur that more transparency could yield better bottles. Winemaker Clark Smith discloses the chemical and mechanical treatments he uses, and he feels that keeping high-tech methods under wraps “squelches the free flow of information,” so that adjuncts aren’t applied skillfully. Grahm, for his part, shares his ingredients in hopes that by showing how few agents he includes, he will encourage others to “rely less upon an alphabet soup of additives.”

I returned from the trade expo curious to know how these additives might influence the flavor of a wine. I’d tried bottles that I’d suspected of chemical massaging because of their price, production volume or taste, some of which had all the subtlety of a liquefied Jolly Rancher. But since the producers I approached chose not to answer my questions, my best shot at figuring out the effects of those agents came down to samples of liquid tannins I’d picked up at the expo. Following the instructions for winemakers curious to test these concentrates in their wines, I set up a mini blind tasting. I poured six glasses of Shinn Merlot—made using only grapes, indigenous yeast, sulfur and tartaric acid—then added to each a few drops from one of five vials, which came in varieties like “fruit enhancer fresh.” I left one glass as a control and tasted all the wines blind.

I’d expected the adulterated wines to be obvious. Instead, only two glasses had a chemical aftertaste, and even then it was subtle; I only detected it after I learned they were ones mixed with liquid tannin. To my surprise—and slight dismay—my favorite glass wasn’t the unaltered Merlot but the one dosed with “mocha.” This (admittedly unscientific) test made clear that, like picking out the differences in flavor between organic and conventional produce, it can be difficult to perceive additives by taste alone.

But the taste of a wine doesn’t tell a bottle’s whole story. There are nuanced, complex wines made using some of these adjuncts, just as there are one-dimensional, unpleasant wines that avoid them completely. However, as with knowing that a chef has used raw-milk cheese instead of Kraft Singles, a list of a wine’s ingredients can offer clues about the producer’s sensibility and craftsmanship and the wine’s relationship to place—all attributes our food-obsessed culture has come to prize. An ingredient label that lists Mega Purple would be a deal-breaker for some who might feel it makes all wines taste the same‒artificial and jammy. For winemaker David Page at Shinn, the presence of adjuncts points to poor stewardship of the land: “As a consumer, it basically tells you that what happens on that particular vineyard or farm is industrial,” Page says. On the other hand, José Santos, the Enartis CEO, told me that he would look at a preservative-free wine like Page’s and think, That is the wine of God—which is vinegar.

In the end, ingredients can provide a shorthand for understanding a winery’s philosophy. Whether you’re uncorking an industrial product or opening a bottle crafted with minimal intervention, knowing what’s in it can reveal the ideals of the winery itself—which may help you decide what you do or don’t want to try. “If I see that 20 things have been put into the wine, it tells me about the whole sensibility of the winemaking ethos,” says Grahm. “Just the simple fact that whoever made it used so many additives would tell me it’s not a wine that I’m interested in drinking.”

Bianca Bosker is the author of Cork Dork, a book about wine, obsession and the science of taste, out next year from Penguin Books.