Vines are among the crop plants that are the most heavily treated with pesticides. They may also be treated mainly with
copper (Cu) and sulfur (S), which are commonly used in organic cultures instead of chemical pesticides but at lower doses.
However, in common with synthetic pesticides, Cu or S may also contain petroleum residues in formulations marketed mainly
for non-organic treatments. We have already reviewed the taste and toxicity of pesticides and Cu in vineyards and wines. As a
part of this trilogy, in this paper we summarize data on the taste and potential toxicity of sulfur in wines, as well as on its use and
role. We underline here that it is protective for life at physiological levels, is produced at low levels by yeasts and raisins, and is
toxic by saturation of the capacity of biological processes.
Sulfur is used in many forms, including mineral forms, and sulfur dioxide or sulfates in vineyards, and for instance sulfites,
such as salts like potassium metabisulfite, in wines. Used at high levels (up to 450 mg/L is authorized in some countries in wines),
sulfites become major fungicides and bactericides. They kill microorganisms, for instance those that do not have sulfite oxidase.
Sulfites and Cu salts are also authorized for use, differently and in general to a lesser extent in organic wines. Today, S is the
major additive in different forms in wines.
Here we characterize the taste of sulfite additives and the sensations that they evoke in volunteer tasters in comparison
to the literature, to complete the comparative data. In the experiments, we tested sulfite additives in water and wines at similar
levels. We also compared them with synthetic pesticides and Cu. Sulfites are irritants from 10-30 mg/L in water. Tasters were
able to detect sulfites in a wine spiked in a blinded manner to a level of 30-90 mg/L. This was found to clearly modify the taste of
wine. Sulfites at high levels break the complexity of nose and mouth sensations, according to specialists, especially for red wine.
They dry and acidify the tastes of wines. As for Cu, natural sulfites cannot be considered as comparable to the petroleum-derived
synthetic pesticides present in non-organic wines from any point of view. By contrast, high levels of sulfites do have grossly
acute effects comparable to those of synthetic pesticides, taste-wise and toxicity-wise; however, the classical chemical pesticides
have more chronic toxic effects. We were able to differentiate Cu and S toxicity levels in organic and non-organic treatments,
due to the combined effects of petroleum derivatives in formulations in the latter case. The environmental impact of high sulfur
treatments in non-organic vineyards and wines today appears to affect biodiversity, drinkability, taste, and health. Some tastes
of Cu, S, or chemical pesticides may have been previously attributed to other characteristics of wines. The chronic toxicity of
chemical pesticides is not negligible in comparison to that of alcohol, it could enhance its effect. Finally, taste could serve as a
toxicity detector in wine.
Copper; Pesticides; Sulfates; Sulfites; Sulfur; Wine
ADI: Acceptable Daily Intake; Bw: Body weight; Cu: Copper: EU: European Union; S: Sulfur