Coffee Bag
If you’ve ever bought coffee grounds in a bag before, you might have noticed that there’s usually a tiny hole in the packaging. Although most people think this is so you can smell the roast before you go home and brew a pot, it’s actually to prevent the bag from exploding! When coffee is roasted, it releases a certain amount of carbon dioxide, which can cause the bag to inflate and burst. However, oxygen can cause coffee to turn stale—which is why the hole is small enough to let CO2 out without allowing oxygen in.