Why do coffee packs have an aroma hole if it is recommended to store coffee in an air tight container If it's recommended that coffee should be stored in an air tight container then why do coffee bags have an aroma hole.
Apart from being able to smell the coffee is there another purpose to this? I would've thought that it would be better to not have a hole at all and that it should be air tight.

It seems the hole at the bottom is probably for degassing but I have seen on some packages that they call this an aroma hole.
It's actually a one-way valve &amp; it's critical to the shelf life of the coffee and the preservation of the bag itself.
When coffee is fresh roasted, it releases carbon dioxide. It's basically a by-product of the roasting process. When the coffee is ground, carbon dioxide is released expeditiously. If you simply place fresh roasted coffee in a completely sealed bag, the bag will expand and in most cases rupture.

http://beanfruit.com/blogs/news/15152773-whats-that-thing-on-my-coffee-bag