Go

[shrimpchips]

Liquid nitrogen stays liquid in insulated containers not under pressure - the rate of evporation is considerably lowered so that you need to replenish it only once every few weeks/months depending on how often the container is opened.

It's how we store cells and tissues for long term storage. Cryopreservation of mammalian cells is well established and routine - it's actually pretty easy to do, and you can store tissues and cells for decades.