Roasted Coffee Bags with Pressure Valve 

The Problem: Even after coffee is roasted, the beans continue to release CO2 gasses, which if not properly vented can give the coffee a "gassey" aroma and flavor. Unvented ziploc bags can actually blow up like a balloon after filling with freshly roasted coffee, and the more coffee they hold, the more pressure is generated. Sealed coffee bags which are unvented, often blow open after being stored due to the pressures caused from the release of the gas. The more oxygen the coffee is exposed to, the faster it loses its aroma and freshness.