I. Basic principle of one-way valves
A one-way valve is a valve device that allows gas to flow in one direction only.
II. Function of the breathable valve
1. Releasing carbon dioxide
During the roasting process, coffee beans undergo a series of complex chemical reactions, producing large amounts of carbon dioxide. If these gases cannot be released in a timely manner, they will accumulate inside the packaging bag, creating a high-pressure environment that accelerates the oxidation process of the coffee beans. The presence of a one-way valve allows carbon dioxide to escape, reducing the pressure inside the packaging bag and slowing down the oxidation rate of the coffee beans, thereby maintaining their freshness.
2. Preventing Oxygen Invasion
In addition to releasing carbon dioxide, another important function of the one-way valve is to prevent external oxygen from entering the packaging bag. Oxygen can react with the oils and volatile compounds in coffee beans, leading to the loss of aroma and deterioration of taste. The valve's sealed design ensures that only gases can flow out in one direction, preventing oxygen from entering and creating a low-oxygen, dry storage environment for the coffee beans.
3. Regulating humidity
Coffee beans are sensitive to changes in humidity. Excessive humidity can cause mold growth, while insufficient humidity may lead to excessive dryness. In coffee bean packaging with one-way valves, water vapor is expelled alongside carbon dioxide, and the packaging material's inherent breathability allows for minor adjustments during periods of low humidity, maintaining a relatively stable humidity range inside the packaging. This facilitates the long-term preservation of coffee beans.