An unfinished bottle of alcohol doesn't have to go to waste; cork it or screw the cap back on, store it properly and it can last for some time. The exact shelf life of an opened bottle depends on the kind of drink it contains; alcohol, sugar content, acidity and other factors can all affect the length of time the contents will keep their quality.
An opened bottle of beer begins to lose its flavor and carbonation almost immediately. If you have a bottle you'd like to preserve, seal it and refrigerate it right away. Since most beer bottles have caps rather than corks, you'll need a stopper to close the bottle. The beer should keep for up to three days, although some loss of carbonation is unavoidable.
Contact with air spoils beer more quickly; to get as much extra shelf life as possible, use a vacuum pump to draw air out of the bottle. You can use this trick with any kind of alcoholic drink.
An opened bottle of wine quickly begins to oxidize, losing its flavor and becoming undrinkable. Most wines oxidize after two or three days, although careful storage can extend the life up to about a week. Red and white wines with higher levels of acidity, such as Riesling or Sauvignon Blanc, oxidize less rapidly. To get the longest possible storage time, take the following precautions:
- Reseal the bottle immediately.
- Refrigerate the wine.
- Avoid contact with sunlight.
- Minimize the wine's contact with air by transferring it into a smaller bottle if the bottle is mostly empty.
Fortified wines such as sherry, port or Madeira last even longer than most wines; their high alcohol and sugar content keeps them stable for weeks or more; a bottle of port can last up to a month, and Madeira can last almost indefinitely.
Because of their relatively high alcohol content, liqueurs can last indefinitely as long as they're kept tightly closed. However, there is an important exception to this: cream liqueurs or liqueurs that contain egg can curdle in warm temperatures and need to be refrigerated promptly once opened; they can last up to 18 months.
Spirits such as gin, vodka, rum, tequila or whiskey have a high enough alcohol content to make the shelf life effectively indefinite, even once opened. However, over time these liquors experience some loss of flavor; whiskey connoisseurs, for instance, may note that a bottle of Scotch loses some of its subtle and complex taste after a year or two open. As with all alcoholic beverages, exposure to oxygen is the cause, so minimizing contact with air can prolong a bottle's lifespan.