The other night I had a most amazing dream, dreaming of a Cabernet Franc that just blew me away. There are a few local (South Africa) examples that blow your socks off, but then there are a dozen ugly Betties. What makes this variety so fickle, with a Jekyll and Hyde personality that sometimes makes you smile, and other times cringe?
Cabernet Franc in its best form is the reason Cheval blanc is amazing, and it is one of the parents of Cabernet Sauvignon. From noble descent yes, but where do the white trash, green and yucky traits come from?
Cabernet Franc has two weaknesses in its armor and one being its susceptibility to virus infection. Cabernet Franc has often been used as an indicator plant to test for the presence of virus, and this leads to vineyards that once performed amazingly in their youth, to become amazingly bad by the time they reach their teens. One vineyard I can remember was a five star winner in Wine Magazine in its youth, and when it was about 15 years old it was one of the worst blocks on the farm. By then another Cabernet Franc vineyard that was still young became the crown prince of this beautiful piece of terroir.
The other chink in its armor is its tendency to produce a huge amount of green flavours. Once green flavours enter a cellar, it will survive a nuclear attack with only the cockroaches to keep it company. It is just about impossible to get rid of. The best way to prevent greenness is to follow vineyard practices that prevent green flavours. One of the few analysis that seems to correlate with greenness is malic acid and this is also correlated with very dense canopies. There is actually a direct relationship between the amount of leave layers over a bunch and green flavours. The simplest way to prevent greenness in the cellar is to error on the high side with sugar ripeness when picking, to prevent dense canopies, and to expose of bunches as much as possible.
To say that you can do nothing in the cellar to combat greenness is a bit of a stretch, but for all practical purposes it is true. Many ways have been described to bring down greenness in the cellar, but the exact impact you will have to determine yourself. Besides these methods, that I will describe in another post some time, the only treatment that is suppose to help is basically cooking the wine, which is simply not on.
Interesting enough, the Asian Lady Beetle (Ladybug) that has caused lots of havoc overseas, produces exactly the green flavours in wine that we want to avoid. Hopefully research to combat the flavour induced by the ladybugs, might just give us the answer to fixing green flavours in wine.