It may be the CO2 in the wine. I find it gives wine a sour taste, similar to ginger (the root). You have to be sure to degas the wine correctly to avoid having such smells/tastes in your wine.
MOD EDIT: Sig only takes up 6 lines now. Fermenting: Apple cider x 2, Doppelbock, Red, Oatmeal Stout, West Coast IPA x 2
Bottle conditioning: RIS
Keg conditioning: La Fin du Monde clone
On tap: Maudite clone, Double Munchen, Oktoberfeast, Oktoberfest Pilsner
Planning: Brewed in 2011: 22 (2010: 15, 2009: 29, 2008: 21, 2007: 1)
Wine made in 2010: 6 kits (2009: 19, 2008: 30)