In order to prolong the flavor and quality of coffee beans, we usually put the coffee beans into a sealed bag after roasting, but the coffee beans will absorb carbon dioxide during the roasting process, and will slowly release after being placed at room temperature. After 100 grams of coffee beans are roasted, about 500 ml of carbon dioxide will be produced. Obviously, if the freshly roasted coffee beans are put into the packaging bag, it will burst. In order to ensure safety and quality, more carbon dioxide must be removed. There are three commonly used storage methods for food bags and food packaging bags: (1) ordinary packaging; (2) vacuum packaging; (3) inert gas packaging; 1. Ordinary packaging ordinary packaging simply isolates coffee beans from moisture, because The coffee beans are in contact with the air for a long time, and the oxidation is serious, which will shorten the taste period. In order to prevent the packaging bag from bursting due to exhaust, we will choose to install a single-sided ventilation valve on the bag to discharge the excess gas. The principle is to use the density of carbon dioxide to be higher than that of oxygen. While the coffee beans are continuously releasing carbon dioxide, they will squeeze the oxygen with the lighter density out of the bag. This extends the shelf life of coffee beans. This method has a disadvantage. Its aroma will be discharged with oxygen, which has a certain impact on the taste of coffee beans. It is often used to store cold coffee beans. 2. Vacuum packaging The premise of vacuum packaging is that the carbon dioxide of the coffee beans must be completely discharged, otherwise the expansion bag of the packaging bag will rupture and lose its function due to the self-exhausting of the coffee beans. The advantage of vacuum packaging is that it can be stored for a long time and the taste will be greatly preserved. 3. Inert gas packaging The use principle of inert gas is similar to that of ordinary air packaging, but the air is replaced with inert gas. Implementation method: 1. First vacuumize the coffee bean packaging bag, and then inject inert gas into the bag to balance the pressure difference in the bag. 2. Fill the bag with the liquefied inert gas, and squeeze out the air through the evaporation of the inert gas. Coffee beans packed through inert gas generally have a shelf life of 3 times longer than those that have been evacuated. Of course, the premise is that they have to use the same packaging materials and have the same oxygen and water permeability. The pressure in the package will saturate with the pressure after the coffee beans are exhausted after sealing. By adjusting the conditions of the inert gas it is possible to change and control the shelf life of the coffee beans and affect their flavor. In order to prevent the air pressure in the packaging bag from being too high, the coffee beans should also be exhausted before being loaded, or a packaging with a one-way exhaust valve should be used.