Ill answer this one, once off the aging rack they will stop aging and do not have a best if used by date, you can also take a potion off the rack it will stop its time and if added to the rack again (same one thats already started aging) it will resume the aging process again from where it left off when removed. So if your going on vacation and dont want your potions to spoil you can take them off the rack and then put them back on when you return