I used to open and sample every bottle I bought as soon as possible. I've just recently developed the discipline to actually keep some bottles unopened for awhile as I whittle down what's already been tasted - probably have somewhere between 15 and 20 bottles open right now. Most have the cork stoppers. Does anyone have a good sense as to the rate of evaporation? I wouldn't think I'm losing too much product too quickly - but if anyone can set me straight, I'm all ears.