How long do powders like tapioca maltodextrin last?

[bigchef]

I've made up a bunch of different powders using tapoica maltodextrin but there is a lot left over. Anyone know if it will keep? For how long? Does it need to be refridgerated or can I keep it sealed on the shelf for a while? Any thoughts?

[Borgstrom]

I've kept some powders as long as a week or so; no experience beyond that. Key point is to keep the powder dry. I put a desiccant pack in with the powder, all in an airtight container.

[Kerry Beal]

I like that "keep your powder dry". I've had a bag of tapioca maltodextrin for at least two years and it's still going strong.