I have personally not tasted Chateau Cantenac (I assume you are not speaking of the higher-end Boyd-Cantenac or Brane-Cantenac, but the lower-level St. Emilion). The lower level 2000's should be drinking nicely now, with the higher-end more structured ones needing more time. If you want to look at other's opinions try https://www.cellartracker.com/wine.asp?iWine=321170
Looks to me like it would be drinking nicely now. And BTW, its unlikely that its a 1L bottle you, not really the norm the area. More likely a 750ml or 1.5L.
Zinman, my wife and I opened a bottle (750mL) a couple weeks ago and it is indeed drinking beautifully. Great fruit and balanced acidity with integrated tannins. Long finish. If I had to give it a score (based on my scale), I'd say LP91-92. Very enjoyable and went well with rib eye on the BBQ.This message has been edited. Last edited by: DoktaP,