Dr. Andrew Waterhouse at UCD gave a talk on May 19th on his research into the effect of oxidation on wine chemistry. I didn’t attend the presentation, but the Trellis Alliance sent out an email with a link to his slides. In them he makes a provocative comment about a possible chemical explanation for terroir.
Note: I’ve only just glanced at the slides, and I am certainly nowhere near the most qualified person to be interpreting Waterhouse’s advanced research. If what I outline (in very rough terms) below is in error please help enlighten me and my readers by leaving a comment or emailing me.
From what I’m able to gather from the slides, Waterhouse and Laurie have identified (or postulated, it is unclear from the slides) a “ferrous regeneration by phenolic reduction” step in the wine oxidation process that influences the way in which wines age (see the right side of the slide above). The ferrous regeneration step is one source of Hydroxyl radicals, extremely reactive neutral hydroxide ions, that are an important part of the oxidation process.
The take away seems to be that if the initial supply of iron in wine comes from the soil, then wines from soils that impart different levels of iron might age differently. While this theory doesn’t seem to explain young wines that taste of place, many vins de terroir do seem to acquire more distinctiveness as they age. This may be why. Waterhouse even asks in his slides: “…could differential amounts [of iron] in soil affect aging? (Is this a chemical explanation for Terroir?!!)”
Interesting stuff, and more grist for the terroir debate mill.
