A WINEMAKER’S WONDERINGS: The Copper Conundrum

copper

Our lives are inextricably linked with the element copper. Electrical wiring, computers, most water pipes, coinage, biomedical technology and numerous chemical uses would be impossible without copper. It possesses germicidal properties and is used in hospitals. It is an essential trace nutrient in the diets of all animals and higher plant life. We turn on a light and experience the wonders of copper’s conductivity. We whip egg whites in a copper bowl and marvel at the chemical reaction that creates greater volume and stability. Farmers spray copper on plants to prevent fungal diseases like downy mildew. Copper is even used in winemaking to eliminate unattractive odors.

However, as with most helpful materials we source and use, there is a price—usually unknown, sometimes ignored—we pay for access to and use of copper. The mining of virtually every useful element or mineral is fraught with negative environmental and human health implications, as is the smelting and purification processes that convert these materials into a usable form. Copper is no exception.

Entire towns like Copperfield, Utah, no longer exist because of the mountain-destroying open-pit mining that defines the copper industry. An abandoned copper mine in Yerington, Nevada, is the source of uranium groundwater pollution in people’s home wells. A visit to the Web site of the Kennecott Copper Mine (kennecott.com) is illuminating and is both hopeful and truly terrifying: the industry has come a long way in terms of mitigating environmental damage, but a quick glance at the six-minute video “From Ore to More” makes you realize the cost of our modern wants and needs. Much of the copper we use is mined in countries like Peru, where there is even less oversight.

Copper has been an essential part of winegrowing for the last 150 years or so. Bordeaux mixture (a mix of lime, copper sulfate and water), first developed by Pierre-Marie-Alexis Millardet, a botany professor in France in the 1880s, has been used as a fungicide for downy mildew for generations. It is also used to combat potato blight, peach leaf curl and apple scab. Copper is in fact approved as a fungicide by the Organic Materials Research Institute (OMRI), the standard for the American organic farming industry.

Yet the toxicity of copper that remains in the soil is well documented. At elevated levels it can be lethal to plants and animal life, contaminate groundwater and remain in the soil forever; just the application of copper turns the vines and leaves an eerily blue hue. But many people criticize the use of newer “conventional” fungicides even when they may be less harmful to the soil and environment.

Copper is also used in the cellars of wineries. For generations, copper piping, fittings, coils for temperature control and other objects like jugs were used, leaching copper into the wines being created. No one knew how much residual copper was in the wines, but the inadvertent copper addition solved the problem of stinky aromas (rotten eggs) by reducing sulfur compounds like hydrogen sulfide. Today stainless steel is “de rigueur,” and has replaced copper in the cellar, so winemakers now add minute quantities of copper to wines to “fix” these sulfide issues, when necessary.

Of course there are legal limits, but these don’t make much sense either. In the USA you can add up to 6.0 mg per liter of copper to wine, but there may only be 0.5 mg per liter in the finished wine. This gets even stranger when you realize that in the EU you can have 1.0 mg per liter in the finished, bottled wine. Are Europeans more tolerant of higher levels of copper in their diets? But wait, you can go to the pharmacy in the USA and pick up multivitamins that contain from 1.0 mg to 2.0 mg of copper in each pill, and people are popping those daily. And what about those copper bowls, pots and pans we are using in our kitchen? How much copper is leaching into our food? And if you live in New York City in an older building with copper pipes, how much copper is in that water?

Ultimately, there is little clarity for producers and consumers when it comes to a “natural” element like copper, especially when you dig deeper into the compromised reality our modern, industrial lives create. Most people I know, and I think the readers of this magazine, want to do the “right thing”—making and eating the most natural wine and food we can; treating our land with care and respect in anticipation of handing it on to the next generation in better shape.

In fact, as words like “sustainable,” “organic” and “natural” enter our eating and drinking lexicon, my business partner, Larry Perrine (a soil scientist), has been provoked to undertake an independent research project examining all the materials that are used in our viticultural and vinification practices—looking not only at copper but at sulfur, Stylet-Oil, ammonium nitrate, and other substances from source to farm. (He will share his findings online.) Not to prove that one is better than another, or right or wrong. Rather, to honestly understand and come to grips with what these materials are, where they come from, how we get them, how they are made, and when and why we use them; thus accepting responsibility for the various and mixed effects on the life, land and products they were used on. Copper is just the tip of the iceberg.

James Christopher Tracy is the winemaker and partner at Channing Daughters Winery in Bridgehampton, as well as a student candidate for the Institute of Masters of Wine.

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James Christopher Tracy is the winemaker and a partner at Channing Daughters Winery in Bridgehampton.