The SOMM Journal

October / November 2016

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Page 28 of 132

28 { THE SOMM JOURNAL } OCTOBER/NOVEMBER MINERALITY—WITHOUT QUESTION THE most controversial and elusive of wine descriptors. This comes as no surprise given that the exact definition of what minerals themselves are is still under debate and has been expanded as an element or compound formed through "biogeochemical" processes. Nutrient or dietary minerals—single ele - ments like manganese, potassium, magne- sium, iron, phosphorus, calcium, copper and zinc—are minor components of red wine. White wines have small amounts of iron, calcium, potassium, phosphorus and zinc. A serving of wine can also contain several milligrams of halite, the mineral salt (sodium chloride is the chemical name for salt), and we can accurately describe its taste in wine as saline minerality. Knowing that wine contains minerals, why is describing minerality so problematic? Largely because aside from halite, nutri - ent minerals are essentially tasteless. Only when they're in a highly concentrated liquid form, for example as a dietary supplement, do they taste offensively bitter. But the elusive flavors we describe as "mineral" in some wines can be readily attributed to specific compounds. The two of the most common are TDN (1,11.6-trimethyl-1,2-di - hydronaphthalene), which is the source of petrol notes in Riesling, and benzyl mercaptan, the source of smoky or flinty notes to Sauvignon Blanc. TDN is found in all internationally important varieties and at high enough concentrations it can be considered a flaw or fault. Wines with higher levels of malic and succinic acids are also perceived as being more mineral while winemaking choices can work to suppress minerality. A recent study from the University of Oregon reveals that low pH soils have fewer nutrients which in turn raises the pH in finished wine, a fac - tor that works to diminish the expression of minerality. Whereas soils with high pH protect acidity in the grapes and, when not suppressed by winemaking techniques like malolactic fermentation or de acidification, acidity enhances the expression of minerality. Viewed holistically, minerality is a complex combination of factors. Research conducted at U.C. Davis by microbiologist Dr. David Mills has proven that grape must mirrors the bac - terial and fungal communities—the microbial terroir—in the soil where the grapes were grown. Mills's study identifies significant regional patterns in the structure of microbial terroir and found that those patterns vary widely across a region and from region to region. Giving winemakers a greater ability to distinguish growing regions based on their unique microbiomes would allow them to select for sites that express greater or lesser amounts of minerality or other characteristics. Having a working understanding of both the positive and negative aspects of anything that we could encounter in a glass is essential to being able to evaluate wine consistently and accurately. When it comes to structured white wines, differentiating between tannin and dry extract will go a long way towards informing quality and style. In Defense of Dry Extract Whether or not tannins are perceptible in white wines depends entirely upon how they are made. If the winemaker has destemmed the fruit, has quickly and gently pressed the wine off the skins and if the wine hasn't seen any form of wood, the answer is unequivocally "no." The structure that you're detecting can be attributed to dry extract (DE), the non-volatile matter or dissolved solids that are left if you were to remove the water and ethanol from wine. We can't see DE, but we can feel it via our mechanoreceptors that sense texture. Gouveio, the classic white grape of the Douro Valley, is a white wine loaded with dry extract. On average, white wines can have between 15–20 grams per liter of dry extract, while red wines typically average 20–30 g/l. Gouveio can clock in at 44 g/l DE, and if it's tasted in an opaque glass, you're likely to think it's a red wine with plenty of tannin. Other white varieties that can have generous amounts of DE and typically never see any oak are Carricante from Sicily's Mt. Etna region and Picpoul de Pinet, the lip- stinger from the Languedoc, to name a few well-structured favorites. Red wine styles that are enhanced by dry extract include those like Amarone, which is made using the appassimento drying method, that concentrates both sugars and solids. Amarone even has legal limits for dry extract, 28 g/l and 32 g/l for reserve. But it's certain styles of Sherry that deliver the most dry extract, as solids are concentrated through oxidative solera aging techniques. The next time you hold up your glass to examine it for legs; it's not glycerol you're looking at, as it doesn't contribute much due to its low concentration, but a combi - nation of dry extract and alcohol. { scents and accountability } Dry extract (DE) is the non-volatile matter or dissolved solids that are left if you were to remove the water and ethanol from wine. Your Glass Half Full . . . OF MINERALS AND DRY EXTRACT by Deborah Parker Wong PHOTO: KARI HOGLUND VIA THINKSTOCK

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