Winetech Technical Yearbook 2022

The other wines, despite the grapes hav ing been exposed to smoke, and having higher volatile phenol levels, were not over whelmingly smoky, and showed attributes which included ‘berries’, ‘floral/ violets’, ‘prunes/raisins’, ‘vanilla/caramel’, ‘tobacco’ and ‘pencil shavings’. High fruit intensity seemed to mask any sensory contribu tion by the VPs present in these wines, as has been indicated by previous work. Our own South African research 7 showed that guaiacol could contribute ‘sweet, woody’ notes to wine and French workers 8 found that VPs could enhance red wine esters (‘sweet, fruity’ notes). In fact, in the wines we investigated, guaiacol (even at higher levels) did not seem to be correlated with a perception of ‘smoke’ in any of the wines unless it was in combination with oth er phenols. 9 Oakwood also contributes a range of volatile phenols including guaiacol, 4-methyl guaiacol, the furfurals and euge nol, and nobody complains too much about the olfactory impacts of those. In fact, the judicious use of a bit of wood might work to help mask some of the VPs by adding sweet, Coming back to my point about chemical composition. So, what if the grapes have been exposed to smoke? It’s not always the case that the wine is an ashy mess, even if the smokiness is there. In fact, it may be that a combination of the ‘subtle, herbal’ notes imparted by fynbos , along with a little smokiness may give our red wines an un mistakable identity in a highly competitive market. It might be argued that a wine con taining some smokiness is more accurately reflecting the landscape of its origin than one that has been stripped of these vintage and terroir effects. Why are we trying to pretend that our indigenous, ecologically necessary fires never happen? The olfac tory space in a red wine is complex, and if grapes have been exposed to smoke, they don’t necessarily need to be written off or banished to an entry-level blend. And it’s not only me that is thinking this way… See Part 2 for the emerging thinking around smoke ‘taint’ in wine. ABSTRACT Discussing the exogenous or external factors that form part of world-famous wine terroir in Part 1, this opinion piece lays out the rationale for well-managed volatile phenols derived from inevitable wildfire events to form a part of our own Western Cape terroir expression. Part 2 shares some insights into consumer reactions to smoke events around the world, demonstrating that wine lovers are not always predictable in their reactions, and quality is in the mind (and on the palate) of the beholder. coconut and spice flavours. TAINT? WHAT TAINT?

FIGURE 2. Olfactory effects of volatile phenols in red wine.

to this that VPs are persistent little beggars that can’t easily be removed or chemically reacted away. This was underlined yet again in a recent comprehensive review of mitigating factors for smoke taint. “Although the issue has prompted a surge in research on the subject in recent years, no singular solution has yet been identified that is capable of maintaining the quality of wine made from smoke affected grapes.” 6 Thus, one is yet again made aware of how much we know as a global industry about smoke taint (the ‘what’ and the ‘why’ are very well covered, specifically by the Australians), but the ‘what now’ seems to have been left out in the cold. Isn’t it time ”THE SUBTLE, HERBAL NOTES IMPARTED BY FYNBOS ALONG WITH DISCREET SMOKINESS MAY GIVE OUR WESTERN CAPE RED WINES A HIGHLY DESIRABLE EDGE IN A COMPETITIVE MARKET.”

we cut our winemaking industry a little slack and took a slightly different view of this issue? WHAT HAVE WE FOUND OUT ABOUT OUR OWN BACKYARD BRAAI? We have been working on this issue consistently at the Department of Viticulture and Oenology, since around 2012 when we graduated our first Master’s student specialising in volatile phenol effects on wine. Since then, at least five Master’s and one PhD have beavered away looking at how we can work with what we have, helping our industry to solve the problem as pragmatically as possible. For example, during 2018, 12 wines were submitted to the Department of Viticulture and Oenology by South African wine industry members concerned that the wines might be smoke tainted. These wines were from regions that had experienced fire events prior to harvest, some bad, some not so bad. The wines were screened for a broad range of VPs, and the results were published in SAJEV. Historical data concerning fire events in the regions from which the wines originated, and during the relevant vintages were also investigated. The wines were evaluated by our “smoke expert” sensory panel and analysed chemically for VPs. The wines contained a wide range of VPs in different concentrations. On the sensory side, out of 12 wines, four were described with negative attributes (‘smoky’, ‘ashy’ and ‘burnt rubber’), at significantly higher levels than the others.

REFERENCES https://www.wineland.co.za/smokin-hot-western-cape-terroir-science-behind/

For more information, contact Marianne McKay at marianne@sun.ac.za.

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WINETECH TECHNICAL YEARBOOK 2022