Why does the bag of freshly baked coffee bulge? Is it really broken?

Whether buying coffee at a coffee shop or online, everyone often encounters a situation where the coffee bag is bulging and feels like it’s leaking air. Many people believe that this type of coffee belongs to spoiled coffee, so is this really the case?

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Regarding the issue of bloating, Xiaolu has studied numerous books, searched for relevant online information, and also consulted some baristas to obtain the answer.

During the roasting process, coffee beans produce carbon dioxide. At the beginning, carbon dioxide only adheres to the surface of the coffee beans. As the roasting is completed and stored for a longer period of time, carbon dioxide will gradually be released from the surface, supporting the packaging.

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Additionally, the amount of carbon dioxide is closely related to the degree of roasting of coffee. The higher the degree of roasting, the more carbon dioxide coffee beans will emit in most cases. 100g roasted coffee beans may produce 500cc of carbon dioxide, while relatively lower roasted coffee beans will emit less carbon dioxide.

Sometimes, the release of a large amount of carbon dioxide may break through the packaging of coffee beans. Therefore, from safety and quality considerations, it is necessary to find ways to release carbon dioxide, while not allowing coffee beans to come into excessive contact with oxygen. Therefore, many businesses use one-way exhaust valves

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A one-way exhaust valve refers to a device that only releases carbon dioxide from a coffee bag without absorbing external air into the bag, allowing the packaging of coffee beans to be in a state of only in and not out, in order to ensure the quality of coffee.

The release of carbon dioxide also takes away some of the aroma of coffee beans, so generally speaking, these fresh coffee beans cannot be stored for too long, even when the quality of the one-way exhaust valve is good.

On the other hand, there are some so-called one-way exhaust valves on the market that are not “one-way”, and some have very poor durability. Therefore, merchants need to constantly test them before use, and you also need to pay more attention when purchasing coffee beans.

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In addition to one-way exhaust valves, some businesses also use deoxidizers, which can simultaneously remove carbon dioxide and oxygen, but also absorb some of the aroma of coffee. The aroma of coffee produced in this way weakens, and even if stored for a short time, it can give people a feeling of “coffee stored for too long”.


The bloating of coffee packaging is caused by the normal release of carbon dioxide in coffee beans, not by factors such as spoilage. But if there are situations such as bursting bags, it is closely related to the packaging situation of the merchant, and attention should be paid when purchasing.

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Ok Packaging has been specializing in custom coffee bags for 20 years. If you want to learn more, please visit our website:
Coffee Pouches Manufacturers – China Coffee Pouches Factory & Suppliers (gdokpackaging.com)

Post time: Nov-28-2023