What is that plastic button on my coffee bag?

That small valve, often a round, plastic button with a hole, on your coffee bag is a one-way valve or aroma valve. Although small, it plays a major role in keeping your coffee beans fresh.

You can read exactly what it does below!

The main function of this valve is to allow carbon dioxide to escape without letting oxygen in.

Degassing, allowing carbon dioxide to escape. After roasting, coffee beans continue to release carbon dioxide (CO2) for a long time. Without a valve, the bag would bulge and could burst.

Keep oxygen out for freshness. The valve prevents oxygen from entering. Oxygen and coffee are not friends. It causes the beans to oxidize, become dull, and lose their flavor.

In short, the one-way or aroma valve ensures that the bags can be sealed airtight immediately after roasting the coffee. This prevents the bags from bulging or tearing, and ensures the coffee does not go stale quickly. The coffee beans can degas without oxygen coming into contact with them.