How long does armagnac keep after opening?

The Voedingscentrum gives no shelf life for spirits with more than 25 percent alcohol by volume: opened and unopened it is unlimited.

Armagnac has at least 40 percent by volume and is well within that. Spoilage in the sense of becoming unsafe is not an issue at this alcohol content. That does not mean nothing changes: aroma and flavour become weaker after months with a half-full bottle.

Drinks with 10 percent alcohol by volume or more are exempt from the best-before date.

That exemption is in Annex X of Regulation (EU) No 1169/2011 on food information to consumers, and SpiritsNL summarises it for Dutch practice. On a bottle of armagnac you will therefore see the alcohol percentage and the volume, but no date.

After opening, armagnac changes mainly through evaporation and oxygen, not through spoilage.

The more air there is above the liquid, the faster this happens. A bottle that is still three-quarters full stays the same for years. A bottle with just a dregs left that stands open for months clearly loses aroma and tastes flatter. The oxidation involved is described in The Oxford Companion to Spirits and Cocktails as a slow process that only becomes noticeable when there is a lot of headspace.

Store the bottle upright, in a dark, cool place, with the cap firmly closed.

Upright matters: with a cork, it prevents the spirit from attacking the material. Dark keeps the colour even. If the bottle is half empty and is going to last a long time, pour the contents into a smaller bottle. Less air above the drink means less evaporation and less oxygen.

No. The maturation of armagnac stops at the moment of bottling.

The cahier des charges counts maturation as the time under oak, counted from 1 April after the harvest. After that no further years are added. A millésime of 1993 bottled in 2003 remains a ten-year-old armagnac, even if the bottle has now been in the cupboard for thirty years.

A bottle that has gone off smells weaker and tastes flatter or more bitter than you were used to.

Cloudiness or flakes in the cold can also occur in an unfiltered bottling; this is not spoilage and disappears at room temperature. If you are unsure about an old bottle, bring it to the shop at Brink 2 and we will take a look together.