If you use a centrifugal juicer, your juice will last up to 24 hours (1 day). If you use a chewing squeezer, your juice will last up to 48 hours (2 days). If you use a Twin Gear juicer, such as the Greenstar Elite, your juice can last up to 4-5 days. In dual-gear juicers, the entire extraction process protects against oxidation, which means that you get fresh juice that stays fresh for longer.
You can safely store fresh juice in the fridge for 24 to 48 hours, depending on the type of juicer you use. The ideal refrigerator temperature is around 35°F to 38°F (1.5°C to 3.5°C). In the refrigerator, fresh juice will last for about a day before it goes bad, approximately 24 hours. However, this is only if you prepare your juice with a centrifugal juicer.
If you prepare your juice with a chewing squeezer, the juice will last for 2 to 3 days, 72 hours and if you have a dual-gear juicer, it will last 4 to 5 days. I don't really like storing fresh juice in the freezer, since over time much of its nutritional value is lost (here's a more detailed article on how to freeze juice), but it can be done, so I thought I should talk about it. However, juice is always best when consumed fresh, as juice can take a long time to prepare. I also like to do enough to make it last 3 to 4 days.
Most other juices (lime juice, lemon juice, carrot juice, and beetroot juice) should be drunk immediately after preparation for best results and nutritional value. While it's normal for the juice to settle, meaning that the darker color will separate at the bottom and lighter at the top, it's not normal for the top of the juice to be brown. In short, freshly squeezed juice should last between 24 hours and 2 or 3 days, depending on the type of juicer and the extraction process you use. However, having frozen juice as a backup is fine and can increase the shelf life of the juice, so I'm not ruling it out.
There is some heat transfer in the mixing process, so the fresh juice you prepare in a blender should last a day or two if you store it properly. Placing fresh juice in the freezer immediately after you squeeze it can last up to six months, but some nutrients will be lost in the process. Just as oxidation takes over raw and cut fruits and vegetables, the same can happen to fresh juice if you don't drink it or protect it soon after you squeeze it. You can prepare your juice the night before and preserve some of the nutritional value by storing the fresh juice in an airtight glass container in the refrigerator.
I talked about orange juice in another article because it's so common (everyone loves vitamin C), but in general, all juices spoil at roughly the same rate. Fresh juice stored in glass jars, made in a centrifugal juicer, will last approximately one day and juice stored in a cold-pressed juicer will last between 2 and 3 days, but, once again, it must be stored in the refrigerator to last that long. As a result, the taste and some properties of the juice are affected; in fact, some consumers believe that this process gives the juice a cooked flavor.