I have been experimenting with vacuum bags and jars, for cooking application of vacuum. Being thrifty i found an easy 1-way valve many of us have at home right now.
What you need is
1. A coffee bag
2. A cutting device
3. A vacuum or in this case a Ziplock vacuum pump, used in their vacuum bag line
Its not perfect, and would probably need to have a piece of tape put over the slits on the front side to ensure the vacuum doesn't leak. As a food safe and easily replaceable 1-way valve, I think it has a lot of possibilities.