Why Your Coffee Bag Has a Tiny Hole

What Is the Valve Made Out of and Where Is It?
The one-way valve is usually made out of plastic and is either glued onto the bag or included as part of the manufacturing process. You’ll typically see it on the front or back of the bag — often either centered or slightly off to the side. It can appear as a little dot, slit or raised button beneath the paper or plastic film. Within the valve is a small flap or membrane, which remains closed at normal pressure. But when pressure from internal CO₂ builds up, the flap lifts just a bit to release gas—then closes again to seal the bag. A kind of pressure-relief system for your morning ritual. The next time you see somebody sniffing a coffee bag and squeezing it like it’s a balloon, well now you know: they’re opening up a little puff of air through that valve, and maybe giving the beans a friendly degassing nudge.

coffee bags
Do All Coffee Bags Need a Valve?
In a word? Yes — particularly for whole beans and fresh-roasted coffee. If you are purchasing beans a few days after roasting, they are likely going to need that degassing period. A valve enables roasters to seal the beans immediately after roasting without waiting for them to settle completely. That means you receive fresher coffee, sooner. Now, not every coffee bag features a valve — and in some cases, that’s fine. For example: Pre-ground coffee: By the time it’s packaged, degassing is typically over. Older roast dates: If the coffee waited some time before bagging, then CO₂ accumulation is less of a problem. Lock so that it doesn’t release the “Coffffee” tattoo from the top of the can Vacuum sealed coffee bricks: These are packed differently and don’t require degassing valves. But if flavor matters to you — and freshness — and especially if you’re buying specialty coffee or from small-batch roasters, a bag without a valve could be a red flag.

How to Open a Coffee Bag with a Valve?
So, now you know why that valve is there. But how exactly do you open one of these bags without ruining it? If the bag has a valve, most likely it might use one of these closures: 1. Hot heat-sealed top with perforation – Simply yank straight across the top where indicated. Easy. 2. Zipper seal under tear – Some bags feature a resealable zipper to help freshness after opening. Rip the top, unzip and scoop away. 3. Tin tie or fold-over design — These are the traditional roll-and-fold style bags with a metal tie to keep contents closed. Simply unroll, unfold, and you’re in. The valve doesn’t change how you open the bag — it just sits there doing its quiet magic in the background. So don’t fret about further damaging it opening the top. Just don’t make the mistake of spilling beans (been there).Do I Have to Squeeze the Bag to Use the Valve?
Not really. The valve is meant to operate passively. Which means it’ll naturally open, off-gassing CO₂ on its own as the internal pressure rises. It will work despite there being nothing you need to do. That said… if you’re the type who enjoys that fresh-poured coffee smell, gently squeezing the bag (like a stress ball, but in a Cheery Mary Poppins Way) will push some of that smell through the valve. It won’t do any harm — and yes, it does smell great. Just don’t Hulk it. All you need is a light squeeze.That little pinhole you see in your coffee bag? It’s not just there for fun. It’s a small but important part of your coffee’s journey from roaster to cup. That little one-way coffee bag valve? It’s a ticket to better flavor and a longer shelf life, along with a more aromatic brew. Whether you’re a casual sipper or a pour-over perfectionist, understanding what that valve is doing — and why it matters — can help you make better choices at the coffee shelf. Look for it next time. Gently squeeze the bag. Take a whiff. And thank the little invention that makes your brew a smidge more mystical. Now, time for another cup.