Minerality: Fact or Fiction

I have never really thought that much about minerality in Pinot Noir, usually associating minerality with higher-acid white wines such as Chablis and German Rieslings. Recently, there has been some ribald discussion at wine tastings, as well as on the internet, about minerality. The central issue seems to be whether minerals in vineyard soils can actually travel up the roots and xylem into the grapes and survive fermentation in large enough concentrations to produce identifiable mineral flavors (for example, flint or slate). Many smart wine people believe this does not happen. They believe the so-called minerality in wine really originates from acidity and sulfur-based compounds that develop in the winemaking process.

Tim Patterson recently wrote an excellent article in Wines & Vines (“Myths of Minerality,” December, 2006) in which he reviewed the limited research on the minerality of wine and offered his own opinions on its origins. He points out that there is no “mineral” on the Wine Aroma Wheel and the creator of the wheel, Dr. Ann Noble, feels that “Minerality is a concept which could never be consistently defined in words or physical standards.” Or as she put it more bluntly, “Sucking on stones doesn’t give any sensation akin to wine flavor.” University of California Davis flavor chemist, Dr. Sue Ebeler said, “There are no clear correlations of any specific compounds with a ‘mineral’ aroma. It is likely a complex mixture of compounds which we associate with the smell of soils or rocky area.”

Patterson points out that minerals such as potassium, magnesium, sodium and calcium are present in wine as salts of mineral acids, but are in such small concentrations they do not significantly influence wine flavors and aromas. More likely, as noted by Jamie Goode (The Science of Wine), sulfur-based compounds associated with reductive winemaking or nutrient stress in yeast during fermentation contribute to what is called minerality. Support for this hypothesis comes from Germany, known for high acid wines, reductive winemaking and nutrient deficiencies in wine musts, where many of the wines are described as sharp, acidic, and highly mineral.