Copper and wine: the whole story

As environmental researchers, we are interested in both organic and biodynamic approaches to growing grapes and making wines. These movements are leading the wine industry away from a serious addiction to herbicides, fungicides, and pesticides, which is a good thing. However, both organic and biodynamic techniques employ certain historical agricultural practices without much critical analysis. One good example is the use of copper to treat mildew.

Copper has very effective anti-fungal properties. It is used as a biodynamic soil amendment, which has produced some controversy. It seems that anytime metals are applied to something we ultimately eat or drink it makes some folks nervous. In response to concerns expressed by some members of the wine community, Alice Feiring posted an email she received from Nicolas Joly, the famed biodynamist and leader of the Return to Terroir.

Joly’s email gives us his opinion on the effects of environmental copper (as well as some amusing analogies), but there are very few facts presented to support his view. While we do not believe that the application of limited amounts of copper is inherently evil, we do believe there are some things we should think about before using copper as a soil amendment. Unfortunately, Joly’s email doesn’t touch on all the relevant topics.

Copper and the Historical Defense

Copper has been used for more than one hundred years to treat agricultural mildew. As in Joly’s email, its historical use is often cited as proof that the use of agricultural copper is benign or at least benign at low concentrations. While we agree that the historical use provides some information with regard to copper’s potential as an agricultural remedy, other parts of the historical record are not all good.

Examination of the historical use of copper includes lots of references to pollution and health problems associated with copper mining and refining. For instance, scientists have reported that copper pollution from Roman and Medieval times is detectable in the shelf ice in Greenland from as far back as 2,500 years ago. For a more recent example, look at Smoke Wars: Anaconda Copper, Montana Air Pollution, and the Courts, 1890-1924 by Donald MacMillan.

Copper and Environmental Stress

An often overlooked element of the copper argument is how much stress producing it places on the environment. To really capture the full effect of using copper, we need to look at the entire life cycle of the copper that is used as an agricultural amendment. Life cycle analysis is a technique scientists use to assess the potential impact of a particular technology or product. So let’s consider copper’s.

First, the copper has to be mined. Copper is typically mined in open pit mines, which are essentially just great big holes in the ground. They are unsightly, and historically open pit mines have ruined the watersheds around them. Outside the US, copper mines have a much worse track record, ruining whole ecosystems and displacing native peoples. While the industry is changing its ways, there are still lots of environmental and safety concerns regarding open pit mining copper mining.

Then, once the copper ore has been extracted, it must be purified or smelted. Copper smelters are not environmentally friendly. Commercial smelters generate thousands of tons of pollution each year including airborne particulate matter, arsenic, and lead. Existing smelters in the US face increasing public opposition as well as official concerns and legal action. For example, several managers of a copper smelter in Washington state face federal pollution and endangerment charges as a result of the pollution from the plant they operated.

Next, the refined copper is transported to the farmer who mixes his/her anti-mildew formula and applies the material to the soil. Like all agricultural amendments, where the copper eventually ends up is an important part of determining its overall impact. Copper is used to control mold, so when it rains more, people necessarily use more copper. But rain leads to runoff, which leads to some of the copper getting into creeks and streams. Copper in rivers and streams kills many different microorganisms that are important to the aquatic ecosystems. Copper pollution of coastal waters is responsible for damage to reefs and other important marine life.

Copper run-off can be minimized if it is used responsibly. Of course, this is the same argument that the makers of commercial fungicides use in defense of their products. An important difference, however, is that no matter the toxicity of the organic fungicides, microbial action and UV radiation will eventually render them harmless. This is not true for metals, such as copper. Copper in the environment may be temporarily stored in a plant or in a bottle of wine, but eventually it re-enters the environment.

Still Consequences — Just Different Ones

We want to be clear that we are not saying that commercially produced fungicides, pesticides, and all the other “cides” don’t cause major problems – there are more than we can report. However, to represent copper as a perfectly holistic biodynamic fungicide without consequences just isn’t accurate. Neither copper nor commercially produced organic products as “cides” can be used without serious consequences – they just have different consequences.

Check out these related posts:

1. Organic, healthy, low environmentally impacting wine, anyone?
2. Organic, biodynamic, and natural wines — What I learned from my review
3. Biodynamic grapes, and the wines they make
4. Organic wine — What is it anyway?
5. Drink wine responsibly, not sustainably