Using Good Produce
Starting with fresh, clean produce is the most important factor in making sure you are serving juice that will last a few days in a refrigerator. If you use rotting produce or produce that has been cut far in advance, it will have already started to oxidize and will greatly reduce shelf life. Make sure you are buying produce from a trusted source, and that you follow health department regulations about cleaning the produce.
Using the Right Equipment
Many times when people are complaining that their juice separates quickly or turns weird colors, it’s because they aren’t using a real juice press. Only a real juice press like a Goodnature juicer will give you that smooth, consistent juice that will last several days.
Juice made on any other technology—including a masticating “slow juicer”, an auger juicer, or a centrifugal juicer—will give you chunky, foamy juice that separates quickly and turns brown. Check out our article on types of juicers for more info.
You must keep the entire juicing process cold. The FDA recommends at or below 41° F (5° C). If you have a refrigerated kitchen that is ideal, but if not, make sure your produce goes from the refrigerator and is made into juice as quickly as possible, and placed back into the refrigerator. You can also use a blast chiller to bring the product down to correct temperature quickly. If you are delivering the cold-pressed juice, you need to keep it at the correct temperature throughout the entire supply chain. Keeping the product cold will improve color, taste, and extend shelf life. You can learn more about this in my article Keeping Juice Fresh – Time and Temperature Abuse
Juice with a low PH (high acidity) will generally last longer than juice with high PH. For example, lemon juice (which has a low PH) will have a much longer shelf life than carrot juice. You should generally try adding acidic juice to your recipes when possible to improve the shelf life. Have you ever wondered why so many cold-press recipes contain lemon? Now you know! Here is a list of various fruits and veggies and their acidity: http://www.pickyourown.org/ph_of_foods.htm.
In cold-pressed juice, the most common form of preservation is called HPP, High Pressure Processing. This is a process in which the plastic bottles of juice are sent through a high pressure chamber, with the purpose of killing living microbes and extending shelf life. This process can extend the shelf life by about 30-60 days on some varieties of juice, but not all.
It’s important to realize that that some companies refer to HPP as “cold-pressure.” Sound a lot like “cold-pressed”, right? This was done intentionally to confuse consumers into buying juice that’s not actually cold-pressed. So, be careful when reading a label. Just because something’s “cold-pressured” does not means it’s “cold-pressed.” Read more in my article The Truth About HPP Juice.
Ok, so what is the shelf life of cold-pressed juice?
Following all of the above guidelines, you should probably be able to get 3-5 days of shelf life from your raw juice, but it can be as low as zero days if any of the above guidelines aren’t followed or other factors cause the juice to go bad.