Fresh lemon juice can do wonders for dozens of recipes. It adds an extra dimension of flavor to pasta or rice, punches up smoothies and juices and is a great addition to plain old water as well. The only downside is that its shelf life is much shorter than bottled, commercially sold lemon juice, so it's good to only squeeze as much juice as you need at one time.
In the Fridge
When it comes to squeezing your own lemons, only make as much juice as you plan to drink right away. Although squeezing more fresh lemon juice than you need is a no-no, if you end up with an overflow, place it in the refrigerator immediately. A storage container with a tight seal keeps leftover fresh lemon juice safe to drink for up to three days when refrigerated at temperatures between 32 and 40 degrees Fahrenheit. After three days, throw the juice away.
During the squeezing process, any bacteria on or inside the lemons can end up in the freshly-squeezed juice. Pasteurization is a process that heats the juice to a temperature high enough to kill bacteria prior to bottling. Fresh-squeezed lemon juice that you make at home does not undergo this process, leaving it susceptible to dangerous bacteria. That's why fresh-squeezed juices require immediate refrigeration after squeezing, according to the U.S. Food and Drug Administration.
The Freezer Option
If you do not intend to use the lemon juice right away, consider freezer storage to keep the juice fresher longer. Simply pour the lemon juice into glass jars or rigid plastic freezer storage containers -- leaving 1/2 inch of space to allow for expansion -- and pop it into a freezer set to a constant temperature of zero degrees Fahrenheit. In these frozen conditions, the fresh lemon juice lasts for up to six months.
Pasteurized bottled lemon juices often contain 100-percent concentrated juice from real lemons and water. The most notable difference between bottled versions and fresh squeezed lemon juice is the additives. Sodium benzoate and sodium sulfite are just two preservatives added to bottled lemon juice that fend off spoilage and prolong refrigeration times. On average, bottled lemon juice keeps for up to 12 months in safe refrigerator temperatures between 32 and 40 F.