Efforts for lowering sulfite levels go beyond consumer demand. It’s also raised the bar on thoughtful farming and winemaking practices.
In their most basic form, when it comes to wine, sulfites comprise a range of sulfur compounds. They are organic, natural, formed during the process of fermentation. They are also added by most vintners during the winemaking process to further safeguard and stabilize their wines.
“A certain amount of sulfites are needed to ensure a wine’s stability,” says Frédéric Lavau, winemaker at Maison Lavau, which has 150 acres of vineyards across France’s Rhone Valley. “We want to make sure we can safely ship our wines to Asia and the U.S., without impacting flavor or quality.”
The interest in low-sulfite wines—among consumers and producers—has been increasing in recent years. Many producers now say sulfites are only necessary in micro amounts.
All wines naturally have some level of sulfites, even before winemakers add more during the production process. Sulfites, as Lavau explains, perform essential duties, preserving wine, preventing rot, acting as a barrier against oxidation and eliminating active yeast, but the level at which they were traditionally deployed simply isn’t necessary, thanks to advancements in science.
‘The Payoff is Worth it’
“High levels are unnecessary,” says Athena Pappas, co-owner and co-winemaker at Boedecker Cellars in Portland, Oregon. “We add 20 ppm or less at crush, depending upon the state of the grapes, just to control bacterial growth. It’s more difficult to make age-able, elegant wine with lower levels of sulfites, but we believe the payoff is worth it. But to do it, we’ve had to give up the lifestyle of hitting the wine with high doses of sulfites and walking away for a three-month vacation.”
Others are lowering their levels of sulfites in wine as they discover more about their impact on flavor and expression of terroir.
“As the market demands unapologetic authenticity, organic farming and limited intervention, including with sulfites, we have worked to meet those needs,” says Daniel Grace, co-owner and director of Il Molino di Grace, which produces 150,000 bottles of certified organic wine in Chianti, Tuscany. “We started lowering our sulfite levels in 2010, and found that it helps us maintain vibrant expression of fruit and terroir. By paying closer attention, we have produced consistently higher quality wines.”
Governing bodies in the wine industry are also pushing sulfur reduction. At the dawn of the 20th century, up to 500 mg/L of sulfur dioxide were permitted in all wines. Today, certified organic wine in Europe only allows up to 100 mg/L for reds, and 150 mg/L for whites and rosés; organic wine in the U.S. allows up to 100 mg/L for all. Lavau, for example, has between 20-50 mg/L in his reds, whites and rosés. In the past decade, Lavau estimates that he has slashed sulfite levels in half, without impacting the transportability of his wines to Asia and North America.
Attentive and Preventive Winemaking
Technology has done more than anything to reduce winemakers’ reliance on sulfur additions.
“Because it’s risky, we need to use all the power of technology to know exactly what’s happening at every step of the process,” Lavau says. “We analyze every level in the laboratory with the Foss WineScan™ machine.”
The WineScan™ machine can be calibrated to simultaneously analyze wine quality parameters, including free and total SO2, in must, must under fermentation, and finished wine. The analysis takes two minutes. Machine prices start around $25,000.
Paul Brock, co-owner and winemaker at the Finger Lakes Silver Thread Vineyard, uses a pH meter reader to measure aeration oxidation before deciding on the level of sulfites needed. He generally lands between 20 and 70 mg/L, but says every wine is different and doesn’t stick to hard, fast rules.
“We look at molecular SO2,” he says. “And the pH. The pH is the most important deciding factor, but it’s not the only one. If there’s a lot of lees contact, you can also lower sulfite levels. Balance is key. Too few sulfites, and microbial levels will get out of control, and that will cause a headache. Too many, and flavors and aromas will be off.”
Randy Meyer, winemaker at the organic and biodynamic-certified Barra of Mendocino Organic Wines, says the industry’s understanding of sulfites has evolved.
“As an industry, we have learned a great deal regarding new techniques to control microbiological stability and oxidation,” Meyer says. “The less you have of each, the less sulfites you need. I’m also a big proponent of preventative winemaking. The more we prevent problems during winemaking and aging, the less we rely on sulfites.”
Extra Vineyard Care
The move toward lowering sulfite levels has also raised the bar on thoughtful farming practices in the vineyard and hygiene in the cellar
“To make low-sulfite wine that can be aged and safely transported, everything begins in the vineyard,” says Florian Serguier, winemaker at the Cotes du Rhone’s Chateau Simian. “We farm very carefully by hand and ensure only healthy and beautiful grapes make it to the cellar. We also protect wine from oxidation with a neutral gas when it’s necessary during vinification steps. That allows us to cut down on sulfites without impacting quality. Irreproachable hygiene, laboratory analysis and frequent tasting is also necessary.”
Meyer agrees, commenting that “good vineyard management, clean fruit, and proper winemaking techniques are key to age-ability. With red wine, tannin is your friend and lessens the need for sulfites. With white wine, controlling oxygen pick-up after fermentation and during bottling helps age-ability—and less reliance on sulfites.”
If lowering sulfite levels forces growers to spend more time in the field, and winemakers to pay closer attention—surely this is a win for all.
Kathleen Willcox writes about wine, food and culture from her home in Saratoga Springs, N.Y. She is keenly interested in sustainability issues, and the business of making ethical drinks and food. Her work appears regularly in Wine Searcher, Wine Enthusiast, Liquor.com and many other publications. Kathleen also co-authored a book called Hudson Valley Wine: A History of Taste & Terroir, which was published in 2017. Follow her wine explorations on Instagram at @kathleenwillcox