We use plant-based preservatives. We use Miron Violetglass for special products. A quote from Miron "MIRON Violetglass is more than just luxurious, purple-colored glass; it is a unique, patented, special blend of minerals that are combined to make a miraculous glass. It is the only type of glass that acts as a filter to block the full spectrum of light, allowing only violet light and UV-A / InfraRed to penetrate the glass. As a result, the nutrients and vitality of natural and organic ingredients that are stored in MIRON Violetglass are naturally enhanced and perfectly preserved!"