It's more stable than Psilocybin, just keep it in a cool dark place and it will last a really long time.
I was reading on BL some dude on there just had some in a ziploc baggie kept in a drawer and after 6 months he noticed no loss in potency...
i think that putting the baggie in a mason jar with some desiccant, in the fridge would help. if that makes sense