Issue link: https://digital.copcomm.com/i/391696
92 { THE SOMM JOURNAL } OCTOBER/NOVEMBER 2014 { wine science } Taking Minerality Literally It is interesting that Bettane brings up mineral water. Frequently, you will see on the side of a bottle of mineral water the differ- ent levels of mineral ions present in that water. These depend on the source of the water, and different mineral waters tend to have subtly different flavors if they are compared side-by-side. Presumably, these differences in flavor, subtle as they are, are down to the mineral composition, although there are plenty who will contend that most mineral ions don't taste of anything. This is the first definition of minerality we are going to explore: the literal one. In this definition, minerality in a wine context is a result of mineral ions, present in the soil, which find their way into grapes, and then affect the flavor of the wine. If a soil has mineral ions in it, these will be taken up by the roots passively along with the water that the roots sequester. However, roots are also able to take up mineral ions selectively in certain circumstances. Some people object that the typical differences in mineral ion concentration, such as those found in different mineral waters, would not be noticeable against the backdrop of the other flavors present in wine. However, the levels present in wine seem to be considerably higher. "Minerals can be detected while tasting a wine," says Olivier Humbrecht, an MW and one of Alsace's leading winegrowers, famous for his advocacy of biodynamic viticulture. "It is the frac - tion on the palate that makes the wine taste more saline or salty. High acids or high tannins do not mean that the wine has lots of minerality. High salt contents make the acidity more 'savory' and therefore less aggressive. Good minerality makes one salivate and makes one want to have another sip or glass or bottle." Gerd Stepp, a consultant winemaker, has some interesting per - spectives of minerality. He broadly falls into the literalist camp. "For me there are two forms of minerality that influence a wine's qualities and characteristics," he explains. "First, perhaps most obviously, the wine's mineral content, which is about taste and texture when tasting a wine. It's much like when drinking mineral water of a high mineral/salt content, there is a flavor/taste and an almost 'osmotic' experience, perhaps similar to drinking sea water, just much less concentrated and less salty." Stepp continues, "Second, I am certain there is an influence on the wine's flavor characteristics through the geology/soils where the grapes are grown, which correlates to the terroir's unique minerality. I understand researchers trying to prove that vines don't actually take up minerals from the soils and that these minerals aren't in the finished product. But how can it be explained that wines made from the same grape variety, vintage and region have such different qualities depending on the soils? It must have an influence, detectable or not." The anecdotal evidence suggesting that some terroirs create wines with much more "mineral" characters is pretty strong. Soils matter. On a recent trip to Alsace, I also encountered some unu - sually long-lived white wines. Their longevity didn't seem to be explainable solely in terms of the usual factors that help whites survive: higher levels of sulfur dioxide, lower pH (higher acidity), and even high sugar levels. The growers who had made these long-lived wines saw the particularly mineral soils on certain sites as the explanatory factor. Of course, there could be a confounder here. Wines with higher acidity are more likely, in my experience, to be described as mineral. Wines with higher acidity live longer, on average. But this brings us back to the observation that differ - ent people tend to mean different things when they use the term mineral in their tasting notes. A few years ago, Californian winegrower Randall Grahm of Bonny Doon Vineyard carried out some interesting experiments. In his quest to try to understand minerality better, he actually put some rocks into tanks of wine. However, in this case the rocks were in a wine environment at low pH, and are therefore likely to release more "minerals" than if they had been in the ground. And the rocks also had the side effect of raising the pH of the wine, which can change the flavor. "Our experiments were incredibly simplistic and gross in comparison to the very subtle chemistry that occurs in mineral extraction in real soils," Grahm recalls. "We simply took interesting rocks, washed them very well, smashed them up and immersed them in a barrel of wine for a certain period, until we felt that the wine had extracted some interest - ing flavors and we were able to discern significant differences between the various types. Olivier Humbrecht, MW, of Domaine Zind-Humbrecht in Alsace: "Minerals can be detected while tasting a wine."