Can I freeze chilli powder? I sometimes make Bulgoki where I use Kimchi powder - the Korean chilli powder Gochugaru. 

However, I can only buy Gochugaru in one kilogram bags. Due to this, I can only get to use about one-third before the expiration date. Does anyone know if I can freeze the Gochugaru in individual portions?
There's no reason why you can't freeze it. Just try and expel as much air as possible from whatever container you're storing it in for maximum longevity.