What is HPP? HPP (short for High Pressure Pasteurization) is a process that many juice companies use to add shelf life to their juice, and preserve it for longer periods of time (usually up to 45-60 days). Which means you are drinking juice that is as much as 2 months old (and believe us, you can taste the difference). While HPP'd juice stabilizes the bacteria and can preserve some nutrients, the quality of the juice is noticeably diminished, and many great things that are in