Unlike some wines, distilled spirits do not age (or mature) in the bottle. This means that your 20-year-old, unopened bottle of 18 year Scotch will taste the same as it would have the first day it was bottled.
However, like beer, certain liquors can "go bad." After months or years, almost any distilled spirit in an opened bottle may lose some of its character, "punch," or flavor.
To really answer this question, we need to break it down into a few categories of alcohol found in the average liquor cabinet.
The Shelf Life of Basic Liquor
The base liquors (e.g., brandy, gin, rum, tequila, vodka, and whiskey) are typically the most stable distilled spirits because they do not contain sugars. These bottles can be stored for a very long time.
- Unopened, these bottles have an indefinite shelf life.
- Once opened, they may begin to lose certain flavor qualities over the years.
The Shelf Life of Liqueurs and Cordials
The shelf life of a liqueur (e.g., schnapps, amaretto and triple sec) is more temperamental because these spirits contain sugar and other ingredients which can spoil. Some are more worrisome than others.
- The more sugar a liqueur has, the faster it will deteriorate (though many of these also have preservatives to combat spoilage - read the label).
- A liqueur with a higher proof contains more alcohol and this should protect it for a little longer than one with a lower proof.
A General Rule for Liqueur Storage:
- Most opened (and well-sealed) liqueurs should last for months and even years depending on its alcohol content and preservatives.
- Opened bottles are likely to lose some of their characteristics due to exposure to air.
Once you begin to see any sugar crystallizing on the bottom, discoloration, curdling or other changes you will want to throw that bottle away. Do a smell and (small) taste test before drinking any questionable liqueurs.
Drink Cream Liqueurs Quickly
Cream liqueurs, those that contain dairy, cream or egg, are a different story. These should be discarded after 18 months or so.
- Liqueurs like Bailey's Irish Cream, Advocaat and Amarula should be consumed within a year of opening.
- Some of their cheaper, creamy counterparts will deteriorate faster.
Even in unopened bottles, these liqueurs will spoil and be undrinkable after a year and a half or more. Some of these touchier liqueurs will include an expiration date on the bottle.
It is unnecessary to refrigerate cream liqueurs, but it can't hurt either.
The Shelf Life of Fortified Wines
Dry and sweet vermouth have a much longer opened shelf life than regular wines. This applies to other fortified wines, as well.
- Typically, vermouth can be stored in an open bottle for at least a few months.
- They can become musty and lose some flavor if stored for too long.
Some people prefer to store vermouth in the refrigerator while others say that is unnecessary. I've done both and have not seen much of a difference.
The Shelf Life of Non-Alcoholic Mixers
Follow the recommended expiration date on the labels of all juices, bottled cocktails (e.g., margarita or bloody mary mixes) and similar mixers. It is best to refrigerate these after opening.
Club soda, ginger ale, and tonic water should be consumed as soon as the bottle is opened or shortly after. If there's no fizz when you open a bottle of soda, then there's no point in adding it to a drink.
If you find yourself wasting a lot of soda when making only a few drinks, buy the miniature bottles. These typically come in packs of six or more bottles or cans. One small bottle of club soda can usually take care of a round of two or three drinks.
- Keep opened bottles tightly sealed. Use the original cap, a replacement cork or a wine stopper that also takes the air out of the bottle.
- Never store liquor with speed pourers unless you're using them during a party. These allow air to get inside the bottle and will quickly deteriorate the alcohol's quality.
- Avoid exposure to extreme heat or cold. Keep your liquor cabinet away from an exterior wall and heat vents.
- Avoid bright, direct light. Consider storing your liquor bottles behind tinted glass if window light is prevalent in your home bar.
- When in doubt, pour the liquor in question into a glass. If it does not look, smell or taste right, it's probably best to throw it out.