Government Warning: Contains Sulfites
Not much is happening in either the winery or the vineyards right now. Our wine is currently resting in the barrels, maturing and developing the mouth watering burst of flavors we're carefully nurturing. Back at the farm, the vines have bloomed, but the berries are still small, hard, green pebbles of fruit. They won't turn purple until around mid-July. The only folks busy are the feds at the FDA. They need to approve our labels far in advance of our first bottling, approving design and verbiage and ensuring all of the required information is present. This includes the ominous line about sulfites. The BATF insists that all wines containing more than 10mg/L of sulfur be decorated with that well-known "Government Warning...Contains Sulfites." "Sulfites" is an almost-dirty word. Urban myths include the oft circulated, "you won't get as drunk or hung-over from wine in Europe because they don't use sulfites." OK, this is absolutely untrue. Their wines contain pretty much the same sulfite concentration as ours, but their governments don't require their bottles to say so, until it's imported into the U.S. Before you protest, just recall the most coveted memories of your last spring jaunt to Tuscany, including that lazy, lingering 3 hour, 5 course dining extravaganza, each magical bite savored with a sip of extraordinary wine. In contrast, here at home, I chase a guzzled glass of pinot with a scoop of cold, congealed Kraft macaroni, as I scrape my kids' dinner into the trashcan with a Disney princess plastic spoon. It's no wonder my head hurts and my eyes are red. It has nothing to do with sulfites; I'm sobbing with despair. Even my mom claims, "I'm allergic to the sulfites in red wine." Actually, white wines have a higher sulfite concentration than reds, partly because the added tannins from the grape skins help preserve red wines better than whites, so less SO2 is required to ensure a wine's stability.
Unfortunately though, it is true that severe asthmatics should be legitimately concerned about sulfites, as some unlucky folks can develop a life threatening anaphylactic reaction. Fortunately this affliction affects very, very, very few individuals. If you want to play ER at home and think you might be susceptible to sulfites, try snacking on dried apricots (a 2 ounce serving has about 112 mg sulfites). If you live to tell, then the measly 10 mg of sulfites in a typical glass of wine should cause no harm (for more information on this, click here). Still, by law, all wines containing more than 10 parts per million of sulfur dioxide must carry the warning label, even if the winemaker never added sulfur herself. This is because sulfur dioxide (SO2) is a natural by product of fermentation, so even organic wines made without adding extra SO2 will carry a high enough naturally-occurring sulfur concentration to require the warning. Should your local, granola-crunching, wheat grass sprouting organic food compound shelf the rare sulfite-free wine, do drink it that night, as without added SO2 these wines wear no protection for long term cellaring.
So why bother with SO2 ("added sulfites") at all? Sulfur dioxide is a multi-purpose wine making tool, which prevents oxidation (i.e. premature browning and aging or spoilage), kills bugs (i.e. it is a powerful fungicidal and bactericidal antiseptic), and enhances gustatory qualities by protecting a wine's aroma. Dosing fresh grapes with a generous blast of SO2 in the fields prevents the grapes from browning en route to the winery. Before fermentation, SO2 holds the unwanted bacterial population at bay, preventing the malolactic bacteria from gobbling up the yeasts' sugar supply. Early in fermentation, a rowdy bacterial population could be disastrous, producing unwanted, smelly, unsavory volatile acidity; SO2 can stop the malolactic bacteria before they even start. Weirdly, although SO2 is fungistatic (i.e. kills yeasts), low doses of SO2 may result in a faster fermentation. And contrary to intuition, even adding SO2 near the end of fermentation won't stop the show; most often it actually facilitates rapid completion (Ribereau-Gayon). I am guessing this because the SO2 kills any competing yeast strains, leaving only the guys tough enough to finish the job and carry fermentation to dryness. Once barreled, wine is frequently dosed with SO2 to prevent premature aging and protect delicate aromas. SO2 binds the chemical ethanal which makes a wine's "flat" characteristics disappear. Once bottled, SO2 will combine with the residual, minute amounts of oxygen in the headspace, over time preventing chemical oxidation. In fact, extended barrel maturation and bottle aging would be impossible without the protective effects of SO2. Of course its use must be judicious and thoughtful, as high doses smell terrible and taste bitter and rotten. But overall, the benefits of sulfur addition far outweigh the cons. No other known winemaking substance can do all of these jobs or do them as well. Rather than strive to eliminate SO2 completely, a winemaker's goal should be responsible use.
The tricky catch is that nobody knows exactly what "the right amount" actually means. EU legislation dictates the upper limits of SO2 as 160 ml/l for whites and 210 mg/l for reds. However in practice, most French wines tap out at about 105 mg/l for whites and 75 mg/L for reds. In the US, Canada, Japan, and Australia, 350 mg/l is the SO2 limit for any and all wines. One reason the nomenclature is so murky is that the effects of SO2 vary with alcohol concentration, pH, and even temperature. As you know, all three of these factors vary significantly over the course of wine development. Sulfur dioxide can also bind to other stuff- like oxygen, ethanal, and other chemicals, but only the "free" sulfur dioxide is active in the winemaking process. And of course, as this is an equilibrium, SO2 binds and unbinds itself as a wine evolves. As a result, free SO2 is measured in the lab, and enologists try to conform to general recommendations for appropriate wine storage (i.e. 10-30 mg/L free SO2 for bottling red wines).
So in conclusion, don't let our label scare you. Drink freely and often; sulfites don't bite.