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WI ne MAKI n G between tannins and anthocyanins which further stabilize color.. Timing is everything Aldehyde bridging is believed to be initiated by a low pH form of acetaldehyde called a carbo-cation. For all these reasons, red wines benefit most from oxygen introduc- tion pre-ML, pre-SO2 . This is when oxygen reactivity is highest, anthocyanins concen- tration is highest and most vulnerable and aldehyde is readily formed and consumed. In the absence of oxygen, non-oxidative polymerization will take place, which does not as readily protect anthocyanins, result- ing in long polymers that cooperatively bind more readily to salivary protein, resulting in drier, harsher mouthfeel. Early cellar choices determine whether oxidative or non-oxida- tive polymerization will predominate. The presence of lees in young reds is del- eterious for two reasons: Lees react readily with oxygen, dampening phenolic activ- ity and suppressing the cascade. Lees also adsorb anthocyanins and contain glycosi- dase enzymes that attack them. Just as egg yolks prevent the formation of a meringue structure, lees must be separated through clarification in young red wine. As with a soufflé, their incorporation after the struc- References 1. "The Solution Problem," Wines & Vines, (Janu- ary 2010). 2. Vernon L. Singleton, "Oxygen with Phenols and Related Reactions in Musts, Wines, and Model Systems: Observations and Practical Implica- tions," American Journal of Enology and Viticul- ture, 38:1:69-77 (1987) 3. Vernon L. Singleton, A survey of wine aging reac- tions, especially with oxygen, Amer. Soc. Enol. Vitic., Proceedings 50th Anniversary Meeting, Seattle pages 323-344 (2000) 4. James Harbertson and Sara Spayd, "Measur- ing Phenolics in the Winery," American Journal of Enology and Viticulture, 57(3):280-288. (2006) 5. Inventor of micro-oxygenation, and a guru of mine. 6. A. Lonvaud-Funel, "Les aspects microbiologiques de l'élevage des vins rouges en barriques." Vme Colloque des Sciences et techniques de la Ton- nellerie. (2000) ture is formed can be beneficial to add fat- ness and richness. The vicinal diphenol cascade reaction is extremely temperature dependent. Because it involves two reactions (one with each -OH group), we label its kinetics of the second order, a fancy way of saying that its temperature dependence is squared. Patrick Ducournau's5 Agfast_WireVise_Jan08 12/13/07 12:34 PM tion was that red wines take up oxygen five empirical determina- times as fast at 59º that a 1º F as at 50º F. This means F drop in cellar temperature can reduce oxygen uptake by one-third. In 2000, research at the University of Bordeaux6 teria in red wine are not inhibited by the pigment-bound SO2 essentially no truly free SO2 pigments in young red wine. It is O2 reported that acetic acid bac- . Because it is in rapid equilibrium, our standard analyses report this as free SO2 , but this is false. There is unbound to up- take by the vicinyl diphenol cascade that protects the wine, and cold cellars suppress its action. This explains why the Pinots of Burgundy's cold cellars are prone to VA. Overripe fruit, as a general rule, also has A report about efforts to re-introduce an 80-year-old method for measuring this critical attribute will be the subject of an upcoming column. very low comparative phenolic vigor—of- ten losing 90% of its reactivity in three weeks on the vine. It is possible to measure the phenolic O2 Clark Smith is winemaker for WineSmith, founder of the wine technology firm Vinova- tion. He lectures widely on an ancient yet in- novative view of American winemaking. Reach him through edit@winesandvines.com. uptake capacity of a wine. Embossed jaws grip the wire as it is inserted and prevent it from being pulled out. The wire is retensionable with a pair of pliers or a claw hammer. Trellis & Fence Wire Anchor WIREVISE® Broken or sheared ends of a wire are slipped into either end of the WireLink to make a secure splice. Requires no tools. Both WireVise and WireLink are available for wire from 9-13 gauge. Tool-free Trellis & Fence Wire Splicer WIRELINK® For your nearest dealer, contact: Toll-Free: 877.552-4828 909.451.2299 • Fax: 909.593-8309 58 Wines & Vines APRiL 201 1