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One-Way Degassing Valve: What Is It?

Kelle Vandenberg

The small plastic one-way valve, or as many folks call it “that plastic belly button thing” in the coffee bag, has become ubiquitous in the specialty coffee trade. It’s hard to remember - let alone imagine - the coffee industry without the one-way degassing valve. Regardless, many new roasters and even more consumers have no idea what that “plastic belly button thing” does for the freshness of coffee, or more recently the efficiency it brings to packaging large laminate bags for products like dry petfood.

PBi remembers how the one-way degassing valves transformed the coffee and played a big role in the proliferation of “specialty coffee”. The valve was originally designed for fresh roasted coffee.  Why? Fresh roasted coffee naturally gives off large amounts of CO2 (gas). The naturally released CO2 creates an overpressure in packages and it must be released from a package. At the same time, the coffee needs to be protected from degradation by air (oxygen stales coffee!).  Prior to the invention of the valve, roasters had tough choices: a) let their coffee “degas in storage ” for up to 72 hours before packaging in a package, like a can, or b) package coffee in porous paper bags. The predicament - cans carry dead coffee, and the paper bags had a limited shelf life (7-10 days).

The one-way degassing valve solved the problem and gives many roasters the opportunity to roast and package fresh coffee immediately. As a result, roasters extend distribution of fresh coffee and expand into markets previously outside their geographic scope.

PBi one-way degassing valves are now used in a variety of applications including large plastic bags that need to be deflated during palletizing.  Some products that use the one-way valve are: coffee, pet food, plastic resin, agricultural chemicals and pharmaceutucals.

Follow this link for detailed information on the PBi one-way valve specifications etc.