Sweetened lime juice is an integral part of many mixed drink recipes, including the gimlet and margarita. Unlike the spirits in your liquor cabinet, bottled lime juice requires refrigeration after you open it and will eventually expire. Although sweetened lime juice is very acidic and the sugar helps to preserve it, it doesn't last forever and should be replaced after its "best by" date.
When Lime Juice Isn't in Peak Condition
Commercially bottled sweetened lime juice has a shelf life of between 12 and 18 months if it hasn't been opened and is stored in a cool, dry cabinet, according to the Still Tasty website. Once it's opened, it will last between six and nine months in a refrigerator set to 40 degrees Fahrenheit or below. Most manufacturers list a "best by" date on the label of the bottled sweetened lime juice, which is a guide to determine whether or not the juice is still at its peak quality. This date is typically 12 months after the juice is bottled. If your juice is more than six months past this date, you may want to purchase a fresh bottle.
When Good Lime Juice Goes Sour
Although freshly squeezed lime juice has a relatively short shelf life of around one week when refrigerated, bottled sweetened lime juice is typically made from lime juice concentrate. This mixture contains lime juice and lime oil along with sweeteners and preservatives. The citric acid in the juice and the added preservatives tend to deter the growth of harmful microorganisms that can spoil the juice. Eventually, though, any mixture of sugar or other sweeteners and concentrated lime juice will become unusable. Signs of spoilage include discoloration, an off odor or an unpleasant taste. Spoiled juice may smell similar to vinegar or wine as it ferments in the bottle.
Pasteurizing and Preserving Lime Juice
Prior to bottling, lime juice is heated to temperatures of around 194 F, or 170 F in the case of concentrated lime juice, to kill any harmful bacteria in it, like E. coli, according to the "Handbook of Fruit Science and Technology: Production, Composition, Storage, and Processing." Not only does this make the juice safe to drink, but it also extends its shelf life by killing off any additional spoilage microorganisms that could later affect it. Along with preservatives like sodium metasulfite and sweeteners like sugar or high fructose corn syrup, the lime juice is able to be bottled and stored without refrigeration prior to opening it, much as canned fruit-based products are.
Fresh Alternatives to Consider
If your lime juice is well past its expiration date or smells funky, you can make your own sweetened lime juice using fresh ingredients. Combine fresh or bottled lime juice with equal parts water and sugar to create your own sweet-and-tart cocktail addition. Make simple syrup from the water and sugar by heating them until the sugar dissolves, then mix in the lime juice and serve. You'll need to refrigerate this version of sweetened lime juice and store it in a sealed container. Because you'll need to use this up within about a week, it's best to make this in smaller batches.