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grapegrowing cite and quartz). Hence the materials are flavorless, for the reasons discussed earlier. Seeing fossil seashells in vineyard soils may prompt us to think of seafood and things maritime, but for the vines, fossils are indistinguishable from any other piece of stone. Fossils in a vineyard bring nothing different to the nutrition of the vines or the composition of the resulting wine. In summary, the various geological matters discussed above can be involved in helping explain the sensation of minerality, but in all the examples, the rocks and minerals themselves remain flavorless. The processes involved are not relevant to the growth of vines or what is in a wine. 16th edition now available! The latest edition provides access to five hours on sustainability (Adobe Presenter) and includes architecture layouts with examples. Topics include: Winery Business Planning Winery Economics Winery Design Winery Equipment Winery Legal Issues Winery Refrigeration Winery Water Requirements Winery Wastewater Treatment Winery Laboratory HACCP Planning Sustainability This CD is exclusively available at practicalwinery.com for $120. A comprehensive work on CD which covers basic essentials of planning and designing a winery. 70 p r acti c al w i ne ry & v i n e yard MAY 20 13 Discussion There is an intuitive attractiveness about the idea of minerality in wine being the taste of vineyard minerals but, in addition to all the difficulties outlined above, it leads to a contradiction about what kind of vineyard situation promotes it. The logic of the idea would have those soils that are able to yield most nutrients to the vine being most likely to imbue the wine with a high (nutrient) mineral content. That is, wines said to have the most pronounced minerality should come from the most fertile soils—just the opposite of what is commonly believed. Most vine nutrition takes place just below the surface, due to some combination of relatively abundant high-CEC clays, humus and mycorrhizae. However, wine minerality is most frequently associated with infertile soils, and especially those that are particularly stony, or where vine roots have to probe deeply into bedrock. Grapevines have low nutritional needs, so it is mainly water that the deeper roots are seeking. At those depths (as well as with stony soils) organic material will be sparse and the geological materials will have had little chance to transform to high-CEC clays. The rock will have undergone only minor weathering. The water will have few mineral nutrients. This is not to say, however, that the anecdotal belief in minerality arising from unproductive soils is unfounded, but rather that any connection must be indirect. For example, it may be that the low nitrogen content of infertile soils leads to grape must in which the yeast has to metabolize sulfur instead of nitrogen. (C. Mullineux, pers. com.) There has been much speculation that minerality may involve sulfur-bearing compounds.9 Moreover, my argument is not that vineyard geology has no role in wine flavor, but that it must be complex, very indirect—and not yet understood. It is well established that very small amounts of metallic elements can influence the course and progress of a host of metabolic reactions in vine metabolism, in the fermenting must, in wine stabilization and in aging. It may turn out, with further research, that the nutrient minerals of geological origin in vines and wines—minuscule in concentration and virtually flavorless though they may be themselves—are pivotal in determining wine character and flavor. However, this would have to be in complex and circuitous ways. Thus perceiving minerality in wine would not involve tasting minerals, but permutations of complex organic compounds whose production has depended on tiny amounts of inorganic cations. Future research will no doubt evaluate this speculation. Meanwhile, the arguments collected here indicate that minerality in wine—whatever that perception is—cannot be in any literal, direct way, the flavor of minerals derived from vineyard rocks and soils. PWV Bibliography 1.Bramley, R.G.V., J. Ouzman, and P.K. Boss. 2011 "Variation in vine vigour, grape yield and vineyard soils and topography as indicators of variation in the chemical composition of grapes, wine and wine sensory attributes." Australian J. of Grape & Wine Research, 17: 217-229. 2.Castiñera Gómez, M. del Mar, R. Brandt, N. Jakubowski, and J.T. Anderson. 2004 "Changes of the metal composition in German white wines through the winemaking process. A study of 63 elements by inductively coupled plasma-mass spectrometry." J. of Agricultural & Food Chemistry, 52: 2953-2961. 3.Ribéreau-Gayon, P., Y. Glories, A. Maujean, and D. Dubourdieu. 2006 Handbook of Enology: The Chemistry of Wine Stabilization and Treatments, Volume 2, 2nd ed. Chichester: John Wiley. 4.Pohl, P. 2007 "What do metals tell us about wine?" TrAC Trends in Analytical Chemistry, 26: 941-949. 5.Coombe, B.G, and P.R. Dry, eds. 2004 Viticulture. Volume 1 – Resources, 2nd ed. Broadview, South Australia: Winetitles. 6.Burdock, G.A. 2009 Fenaroli's Handbook of Flavor Ingredients, 6th ed. London: Chemical Rubber Company Press, Taylor and Francis. 7.Fugelsang, K.C., and C.G. Edwards. 2007 Wine Microbiology: Practical Applications and Procedures, 2nd ed. New York: Springer. 8.Bear, I.J., and R.G. Thomas. 1966 "Genesis of petrichor." Geochimica et Cosmochimica Acta, 30: 869–879. 9.Goode, J. and S. Harrop. 2011 Authentic Wine. Berkeley, CA: University of California Press.