How do you test the freshness of your roasted coffee bean?

ANSWER - For about a month after the coffee is roasted it gives off Carbon Dioxide (CO2). After about a month the coffee beans go the opposite way and try to absorb moinsture from the air. So the best way to find out if you coffee was roasted in the past month is to place a handful of roasted coffee beans in an air-tight plastic coin bag and leave it for a day or so. If it puffs up then the coffee beans are fresh.