Pesticide Fact Sheet

What’s in Your Wine?


People like to think of wine as “just grapes.” But there is a lot more in your wine glass than fermented grapes. For example, yeast is added to aid fermentation. Salts, sugars and acids may be added to control and direct the fermentation process. When we compare the differences between organically-certified wine, wine made with organic grapes, and conventionally-made wine, we need to look at how many chemicals are added and where they come from.

Small amounts of compounds called sulfites are present in all wine, whether it is certified organic, made with organic grapes, or conventionally made. Sulfites, used as a preservative, can be added to all wines at the discretion of the winemaker, even in very small amounts to organically-certified wine.

When making conventional wine, literally hundreds of chemicals can be and are used, not just added sulfites. Some conventional winemakers add sugar, oak chips and flavor agents. On the other hand, (or in the other glass) wine that is certified organic is allowed to have about 70 chemicals added to it, including organic and naturally occurring acids, salts, and enzymes. However, unlike in conventionally produced wine, any chemical used in a certified-organic wine cannot have an adverse effect on the environment or on human health as defined by the Food and Drug Administration.  Source: The National List of Allowed and Prohibited Substances, issued by the National Organic Program (NOP).

Out in the fields where wine grapes are grown, the differences between organic and conventional wine are a lot easier to explain. Conventionally-grown wine grapes can be treated with synthetic pesticides, fungicides and insecticides. Organically-grown grapes cannot be treated with any synthetic pesticides, fungicides, insecticides, or fertilizers.

According to the California Department of Pesticides Regulation, in 2010 25 million pounds of pesticides were applied to conventionally-grown wine grapes in California. That was a 19% pesticide increase from the year before. Conventionally-grown wine grapes received more pesticides than almonds, table grapes, tomatoes or strawberries. Insecticide use increased by 34% and acreage treated with sulfur, a fungicide, increased by 21%.

The Pesticide Action Network (PAN) classifies about a million pounds of those chemicals dispersed on wine grapes as “bad actors,” meaning that they are known or probable causes of cancer, are neurotoxins, or groundwater contaminants.

Roundup, a herbicide, is widely used on wine grapes in conventional farming. A recent study has linked Roundup with health dangers, including Parkinson’s, infertility, and cancers.

In 2010, more than 400,000 pounds of Roundup (known as Glyphosate to the trade) were applied to wine grapes.


What Levels of Pesticides Actually End Up in Your Wine?

There have been several studies that have that examined pesticide persistence in wine grapes. According to pesticide studies most often cited by scientists, fungicides, when applied in the fields, tend to dissipate in the grapes and are present in varying levels in finished wine. While pesticides such as mepanipyrim, fluazinam and chlorpyrifos were not detected in the finished wine, pesticides such as myclobutanil and tetraconazole persisted during the winemaking process. Some pesticides such as azoxystrobin, dimethoate, pyrimethanil were extremely persistent. In fact, their residual concentrations in bottled wine were similar to initial concentrations on the grapes.


 Is the Pesticide Dosage Harmful in Conventionally-Made Wine?

Researchers try to assess pesticide exposure by means of two measurements. One is called the No Observed Effect Level (NOEL), which is the highest dose of a chemical that does not provide an adverse biological effect. The other is called the RfD or reference dose. RfD, which is derived from NOEL, is an estimate of the daily lifetime exposure of a chemical on the human population, including sensitive subgroups, which is not likely to cause harm. The EPA uses RfD as a reference point from which to gauge the potential effects of chemicals at varying doses.

According to studies in 1996 and 2000, out of 12 fungicides commonly used on wine grapes, six of them may persist in the finished wine in amounts that exceed the safe reference dose. Among the nine pesticides commonly used on wine grapes, five of them exceeded the safe reference dose, and three exceeded both the safe reference dose and the NOEL. Among the eight remaining pesticides most commonly used on wine grapes, three exceeded the safe reference dose determined by researchers.

A study found that European wines were also systematically contaminated with pesticide residues. Decanter magazine reported that ninety percent of French wine samples contained traces of at least one pesticide. It’s important to note that pesticide levels detected in the wines tested were “below threshold levels of toxicity,” the European researchers said. But they also pointed out that “we should not forget that it is not the consumers who are most impacted by this, but the vineyard workers who are applying the treatments.”

No pesticides are ever added to certified organic wine grapes.