How Does a Coffee Bag One-Way Air-Valve Work

02 Aug 2020

If you like drinking coffee, you must have found that there is usually a one-way degassing valve in the coffee bag. When you cut it, you will find that its appearance is similar to the one on the right. If you use a coffee bag, you can usually observe that there are several small holes in this one-way degassing valve, which are holes for coffee beans to "breathe" with. These can usually be found on the high-class café before, however, it becomes more and more popular among common supermarket brands.

If you like drinking coffee, you must have found that there is usually a one-way degassing valve in the coffee bag. When you cut it, you will find that its appearance is similar to the one on the right. If you use a coffee bag, you can usually observe that there are several small holes in this one-way degassing valve, which are holes for coffee beans to "breathe" with. These can usually be found on the high-class café before, however, it becomes more and more popular among common supermarket brands.

Why do you need a one-way degassing valve?

The living water in the cells begins to evaporate in the early roasting stage of coffee beans, carbon dioxide is continuously generated during the endothermic process of coffee beans, and the cell walls slowly harden and begin to swell. As the roasting process continues, the pressure inside the coffee beans continues to increase, and coffee crema is brought into the fine pores in the cell wall, creating a sealing effect that retains carbon dioxide and other aromatic substances in the cell wall. This is where the "coffee aroma" comes from. It is worth noting that as long as the coffee beans are roasted, it will continuously generate carbon dioxide in the later period, which is to complete its degassing process.

Another element is the oxygen, the most direct reaction of oxygen to coffee beans is "oxidation". It is one of the culprits that makes coffee lose its flavor. This reaction starts as soon as the coffee beans leave the roaster. If the coffee beans are ground into powder, the surface area of ​​the coffee exposed to the air will be greatly increased, and the oxidation process will be greatly accelerated. Both oxygen and carbon dioxide will seriously affect the freshness and taste of coffee beans, resulting in a great decrease in the optimal taste of brewing. The one-way degassing valve is a small accessory on the food packaging. Its function is to bring the carbon dioxide out of the bag in time while prevent the external oxygen and contaminants from entering into the bag, so that the coffee bean packaging is in a state where the material can only exit but not enter. Thus, it helps to protect the freshness of the contents in the bag.

How does the coffee one-way degassing valve work?

When the carbon dioxide produced by the coffee beans sealed in the bag reaches to a certain pressure, the gas can push the degassing valve from inside to outside to discharge the excess gas; when the pressure in the bag is reduced to the level that not enough to open the valve, the valve closes automatically. The valve will only automatically open when the pressure inside the bag is higher than the pressure outside the bag, otherwise it will not open in order to prevent the external air from entering into the bag. Sometimes, the release of a large amount of carbon dioxide may break the packaging of coffee beans, in this case, a one-way degassing valve can avoid this situation. At present, there are some so-called one-way degassing valves on the market that are not "one-way", and some of them have very poor durability. Therefore, the manufacturer needs to test again and again. At the meantime, you also need to pay more attention when buying coffee beans. Wojin degassing valve has been specializing in the development of degassing valves for seven years, providing consumers with various types of degassing valves. It is a brand you can trust.

Tag: one-way degassing valve

Originally published 02 Aug 2020, updated 02 Aug 2020.

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