micro-oxygenation in contemporary winemaking - Cape Wine ...

Micro-oxygenation in Contemporary WinemakingAccurate recent figures on worldwide sales of micro-oxygenation equipment are notavailable. France remains the largest user of micro-oxygenation with over 2000 units inoperation by 2006, mainly in Bordeaux (Robinson, 2006). A similar number of units havebeen sold worldwide. Uptake has been significant in Italy (Dempsey, 2001), Chile (Goode,2005; Robinson, 2006) and the United States (Zoecklein et al., 2002). For example, in a2007 survey of American wineries, 16% of small wineries, 50% of medium-sized wineries,and 83% of large wineries admitted to using micro-oxygenation on some of their wines(Goldfarb, 2007). Internationally, some of the most high profile producers publiclypromoting micro-oxygenation include Randall Graham of Bonny Doon (Graham, 2003),E&J Gallo (Rieger, 2000), Domaine Chandon (Dempsey, 2001), and Vasse Felix (Otto,2003). The market in South African is still relatively small but the technique has been usedby a number of producers and local sales of the equipment continue to increase(Euroberry, 2008a).Phenolic chemistry is a very important and rich area of wine research. The fundamentalreactions which seem to be implicated in micro-oxygenation were well known by the timethe technique was actually developed (Rieger, 2000).Vernon Singleton and his associates at UC Davis in California elucidated the keymechanisms involved in the oxidation of phenolic compounds in musts and wines in the1970s and 80s (Singleton, 1987). The fact that colour stability in wine was due toanthocyanins reacting with other compounds to produce large polymeric pigments was firstidentified by Pascal Ribéreau-Gayon and Emile Peynaud in 1962 [cited in (Thorngate andSingleton, 1994)]. The work detailing these reactions between anthocyanins and tanninmolecules was mainly completed by Somers in the remaining years of that decade(Somers, 1971). Another very important part of the puzzle was research in the early 1970sthat demonstrated that acetaldehyde (produced from the oxidation of ethanol) was the linkin certain condensation reactions between anthocyanin and tannins (Wildenradt andSingleton, 1974; Timberlake and Bridle, 1976).Of the more recent discoveries which may be of some relevance to the chemistry of microoxygenationare the discovery of the category of compounds known aspyranoanthocyanins (Fulcrand et al., 1996; Monagas et al., 2005; Fulcrand et al., 2006),and research on the central role of iron and copper in the oxidation reactions of phenols inwine (Danilewicz, 2003; Danilewicz, 2007).8