Why do coffee packs have an aroma hole if it is recommended to store coffee in an air tight container

26 Jun 2020

The age group that get used to drink coffee in China is increasing year by year, and the coffee beans sold on the market becomes more diversified. In order to choose the coffee beans that suit you, Wojin Valve reminds that we should understand how to preserve the coffee beans before we make the purchase, which could avoid the decrease on aroma and quality of coffee due to inappropriate storage method. You may find a small hole on your coffee bag if you have ever purchased some professional-grade coffee, which is covered by a white or transparent circular air valve. However, many people do not know the real function of this small hole, and they only smell the coffee bean through the hold by squeezing the bag. They may only think it as a hole to help them selecting the coffee. In fact, it is a one-way degassing valve, which is essential for the preservation of coffee. The roasted coffee beans can be stored for about one month, and the coffee beans stored in a vacuum condition can last for about two months. With the one way valve, the shelf life of coffee can be greatly extended.

Freshly roasted coffee releases carbon dioxide, which is a "degassing" process that all coffee must complete after roasting. After roasting, the internal chemical changes of the coffee beans will continue. At first, you can only smell the nice aroma from the coffee with a sour taste. After 4-12 hours, the sour taste will gradually reduce, and the texture becomes fuller. That is, the taste at this stage is suitable for drinking. However, the best taste can be obtained within3-7 days, and the taste will be rich and mellow. After this 7-day golden period, you will find the bitter taste more and more obvious alongside with a gradual evaporation of aroma.

If you put fresh roasted coffee in a completely sealed bag, the bag will swell and break in most cases. Some people put coffee outside the container. However, oxygen is the enemy of freshly roasted coffee. By exposing the coffee to the air for a long time, it accelerates the oxidation of the coffee and causes the coffee to become sour and deteriorated. If you use a package with a one-way degassing valve, you can discharge the gas in the bag and isolate the external air in time, thereby protecting the product fresh. The one-way degassing valve is a small accessory on the food packaging. The degassing valve is hot pressed onto the bag through the valve press machine. The work of the exhaust valve is a "one-way" degassing process. When the gas generated in the bag reaches to a certain pressure degree, the valve will be pushed and opened by the internal gas, therefore, to discharge excess gas. Other people use the iron can for storing coffee, the patch-type degassing valve can also play an important role on extending the shelf life of coffee since it works the same and brings the same effect. So, you should be able to know why there is an “aroma hole” in the sealed coffee package or container.

Tag: one way valve

Originally published 26 Jun 2020, updated 26 Jun 2020.