David on Technical Topics – How Long Does a Bottle of Cognac Last?

It is surprising how many times we are asked this question.  The answer is, of course, completely different from wine, as the distillation process reduces it to a spirit. There is nothing in cognac which can effectively reduce its life providing air cannot get into the bottle and of course, the spirit cannot get out. Cognac bottles are sealed with a cork and a metal or plastic cap shrunk over the top. On some more expensive bottles a wax seal is used to ensure that the bottle is airtight.  Once a bottle has been opened, the level of cognac becomes significant.  The more air that is in the bottle, the more space there is into which the alcohol can escape.  It is the alcohol that preserves the flavour of the cognac so as the a.b.v. reduces, the flavour changes and eventually it will become undrinkable.  Bottles should not therefore be left containing just a small quantity of cognac nor stored above 25 °C.

The Bureau National Interprofessionel du Cognac tells us that all corks should be changed every ten years since the cork will taint the cognac in the bottle.  At Hermitage Cognacs our experience tells us that with modern corks there is no perceptible change in flavour of an unopened bottle of cognac after twenty years but we do advise that corks are changed at this point.  We also advise that with an opened bottle the cork should be replaced after pouring and the bottle should be stored in an upright position; otherwise the strong spirit will attack the cork and the flavour will be affected.

So, although the flavour of cognac can change over a long period of time, if stored correctly a half full bottle of cognac will not show any perceptible changes in quality for at least ten years.  Happy Cognac Drinking!

To read more Technical Topics go to our Brandy Education page.