Furnitures designers and fellow RISD grads Andrew Bannar and Ben Kicic designed this simple coffee scoop that can be used to hold the bag closed.
“The Closepin Coffee Scoop’s handle forms a simple clip to keep the bag shut while also providing a spot for the scoop when not in use. The scoop is inspired by the traditional Shaker clothespin to which it owes its name and form.”
I like the concept, though I’m not sure it would provide that airtight seal that you want on a bag of coffee.