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54 WINES&VINES March 2017 WINEMAKING PRACTICAL WINERY & VINEYARD W hat is minerality in wine? What are w e e x p e r i e n c i n g when we label wine attributes as "mineral?" Despite frequent current usage, the term mineral as a wine descriptor reflects a rela- tively recent fashion, for which the term ap- pears to have no clear definition. 1,2 When white wines are described sensorially in terms of mineral characteristics, the attributes em- ployed are multi-dimensional, meaning they involve smells, tastes and tactile sensations. Further, they range from stone and soil-related terms (e.g., flinty; wet stones), seashore terms (e.g., iodine and seashell), smoky and gunflint notes, tastes of acidity, bitterness and saltiness, to the kerosene-like notes in Rieslings. 2 The sole clear and consistent aspect is that perceived minerality in a wine appears favor- able in terms of wine marketing, with per- ceived minerality linked to higher priced wines. Conceivably this is because wine char- acteristics interpreted by tasters as mineral (such as flinty, chalky or oyster shell) have an ability to evoke wider concepts via associative memory including the powerful marketing tool of vineyard location, or terroir. 1,2 However, with many viticulturists and more recently geologists including Alex Maltman 3 arguing that we cannot literally be smelling or tasting the vineyard rocks and soils, the ques- tion arises: What are we experiencing that induces us to use terms pertaining to rocks and soil when describing attributes of a wine? Maltman, a professor of earth sciences at Aberystwyth University in Wales, outlined in a recent talk 9 at the Institute of Masters of Wine in London, UK, the disconnect between geological minerals (elements) and the 14 mineral nutrients required by vines, pointing out that "these 14 are not the same minerals as geological minerals." "Elements are not necessarily bioavailable.… Weathering processes are too slow to keep pace releasing nutrients for vegetation year after year, (and) the cycle is interrupted with agricul- ture. Nutrients are removed each year in crops, so we have to add compost, fertilizer.…Most of the nutrients are coming from humans, not the geology," he explained. Added to the conundrum is that minerals do not vaporize. They are odorless, and their concentration in wine is far below the taste threshold. This latter point, however, must be qualified in that sub-threshold tastes and smells have been demonstrated to interact to produce an experience of "flavor." 4 Is minerality in wine all in the mind? If we are not tasting soils and rocks, then what are we tasting? Is the flavor that we describe as "mineral" all in the mind? In one sense, yes. This is because a wine's flavor is not in the wine but in our brain or mind. 5 Flavor is a multi- modal percept created in the brain from wine. That is, when we smell or taste a wine, it is the brain that integrates the various sensory inputs that the wine's composition affords. This is ac- complished via the processes of perception. Perception of a wine's attributes is a complex process involving sensory input via our visual, olfactory (smell by nose; aroma by retro-nasal olfaction), gustatory (taste) and mouthfeel systems. In addition, the context within which we experience a wine (at the vineyard or in a restaurant) can further influence our perception and conceptualization of a wine. 5 Is minerality in wine a sensorial reality or a mental construct? The question is whether there is something we are perceiving in wine that is evocative of stones, rocks and so forth, or whether we draw primarily on ideas and information already stored in our heads, perhaps as a result of clever marketing (top-down or knowledge- based perception), when we employ mineral characteristics to describe what we are expe- riencing in a wine. An example of top-down perception is when memory of chalky soils and fossils observed when visiting a vineyard could bias a taster to actually "taste" mineral characteristics in a wine from a particular vineyard just as color has been shown to bias us to smell red wine characters in white wines that have been colored red with odorless anthocyanin. 5 Mineral Character in Wine Is the perception of minerality all in the mind? By Wendy V. Parr, Jordi Ballester, Dominique Valentin, Dominique Peyron and Claire Grose Minerality intensity judgments (vectors) for each perception mode and the wines evaluated in the study (purple dots) projected onto the two-dimensional space yielded by principal components analysis (PCA). Mineral O = smell only; Mineral G = full tasting; Mineral NC = palate only. Wines beginning with "F" denote French wines; wines beginning with "NZ" denote New Zealand wines. JUDGMENTS OF MINERAL INTENSITY IN FRENCH AND NEW ZEALAND WINES -4 -3 -2 -1 0 1 2 3 4 F2 (24.83%) 2 1 0 -1 -2 F1 (69.44%) Biplot (axes F1 and F2 : 94.27%) Mineral NC NZAVV Mineral O Mineral G NZRSL FSHB NZSVCH NZWWH NZSVA NZAVFB NZRS NZLWB FLCH FLPC FSBI FBCBB FBCLM FSFC FSBAGA