I read that Rusden Wines in Barossa Valley, Australia, Rutherford Wines in Napa Valley & Klein Constantia Wines, South Africa, are changing back from corkscrews to corks, deciding the corkscrws caused the wines to "sweat" producing "overly dominant reductive characters" in the wine. How do you recognize a wine "sweating" & what is wine sweat & reductive characters? Thank you.
Answer From Expert Roger Bohmrich MW
I believe you are referring to the decision by a few wineries around the world to abandon screwcaps and return to cork closures. This is a subject that is highly technical as well as emotional for many winemakers. Over the past several decades, there has been a trend - in some regions and for some wines - in favor of screwcaps, led by wineries in New Zealand and Australia. This resulted from a disturbingly high incidence of unpleasant taint - a wet, moldy odor and taste - associated with a chemical compound in some contaminated corks known for short as "TCA." For the same reason, some opted for corks made from synthetic materials. However, the adoption of screwcaps in particular presented other issues you have cited. Current models of screwcaps (unlike earlier ones) virtually block all oxygen transmission. Consequently - and I'm simplifying a complicated process - wine has a tendency to develop "reductive" characteristics some describe as "sweaty" - not exactly appealing. Slight reduction might appear as a dull aroma lacking expression, and they may disappear as the wine sits in the glass; if severe, the odors could resemble rubber or rotten eggs, but this is very rare. Screwcap advocates contend that winemaking can be adjusted to compensate for reductive tendencies, and this is certainly true. On the other hand, natural corks are consistently cleaner than before due to improved sterilizing procedures, and they permit a small degree of oxygen to enter the bottle. All of this has been exhaustively studied and debated in recent years, and there are strongly divergent views. In short, we could say there are arguments in favor of both screwcaps and natural corks, and the winemaker needs to consider the closure when determining cellar handling.
