Whisky

In many ways, whisky can go much "further off" than other spirits. It always tastes sharper when it's been aged in barrels longer, but after a certain point the whole flavor profile of a whiskey changes and it might not be desirable to drink at all. Burning wood and ash typically give off tar, which coats the inside of barrels and eventually leaches out into booze. The more time your whisky spends in contact with this old charred wood - especially if it is single malt Irish whiskey - the rounder its taste will become and then its taste will start to degrade due to the overdarkened flavours that overshadow other flavours. This phenomenon tends to happen faster because Scotch Whisky isn't typically put into bourbon or sherry.

Scotland is credited with being the birthplace of whisky. The process was invented in the late 1400's by a Catholic priest, a Scotsman called John Anderson, who experimenting with ways to create alcohol from barley. His process involved soaking barley in water that had been boiled then dried over coal and immersed in cold water. Apparently, in March 26th 1494, an order was placed for 'wyskye' where John Anderson shipped his invention to the Abbott of Paisley Abbey near Glasgow.