A Roaster’s Guide to Packaging: Coffee Degassing Valves

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There’s a fair amount of science that goes into crafting the perfect cup of coffee. From the pH of the soil it’s grown in, to the minerals in the water it’s brewed with. Roasting itself triggers a chemical reaction. One that changes the packaging conversation.

Sugars and acids are broken down and carbon dioxide forms. Much of it stays locked inside the bean, initially. But, over the course of up to a month, that gas is released. If you’ve ever noticed bloating after you’ve sealed fresh beans in their packaging, you’ve witnessed this process. While slight swelling may signal that your beans were packaged at peak freshness, it can also put unwanted strain on your seals, compromising the final product.

It’s why many roasters opt to include a coffee degassing valve on their packaging. Many, but not all. Because the decision isn’t as simple as: if you package roasted beans, you need a valve. As with most packaging decisions, there are a few variables to consider.

How a coffee degassing valve works.

As complex as the science behind coffee roasting can be. The degassing valve is a relatively simple and elegant solution to the pressure build up caused by the release of carbon dioxide.

As the pressure inside the bag increases, it eventually becomes higher than the pressure outside. When it reaches this threshold, the one-way valve releases just enough to let the excess gas escape. Once the internal pressure returns to levels below those outside the bag, the valve snaps closed. The packaging is once again sealed tight.

When you need a coffee degassing valve, and when you don’t.

If it sounds like a great feature, that’s because it is. But that doesn’t automatically mean it’s a necessary one. Knowing the variables that come into play can help inform your packaging strategy.

Roast Level

Darker roasts carry and shed more carbon dioxide than lighter roasts of the exact same beans. Lighter roasts also release the gas more slowly. It’s why they need to rest longer after roasting. Hold all other factors equal and your darker roasts push the decision toward including a valve, while your lighter roasts leave room to skip it. Move all the way down the spectrum to green coffee for home roasters and you don’t need to consider a valve at all.

Ground vs. Whole Bean

Grinding opens up all the internal structure of the bean to the surface, accelerating the off-gassing process. You may be inclined to think a pre-ground SKU would require a valve over a whole bean option that vents at a slower pace. But because the gas of a ground bean is released so quickly, the majority of the carbon dioxide dissipates before the product even makes it into the bag. This means ground beans are less likely to benefit from a valve.

Bag Volume

The math on this variable is relatively straightforward. The more beans the more gas there is to manage. Small sample size and single-serve pods don’t require much in the way of venting. Standard retail bags from 8 to 12-ounces produce more gas and could benefit from a valve. If you’re moving even more volume with wholesale and bulk SKUs, the valve becomes a non-negotiable.

Journey from Roaster to Cup

This variable is probably weighted most heavily among the four. If you’re moving from roaster to sealed bag within 72 hours, a valve should be in consideration. If your coffee is resting longer, you may be able to get by without a valve. Shelf and transit time work in the opposite direction. The longer you expect your product to spend in transit or on the shelf, the more likely you’ll need a valve.

All these factors work together to inform your coffee degassing valve decisions. Same-day bagging, darker roast, 12 ounces of whole beans on a slow-moving shelf? That adds up to a valve. Light roast rested for more than a week, packaged in a 6-ounce bag with quick local turnover? Go ahead and skip the valve.

The jobs a valve doesn’t do.

A valve plays one role: manage carbon dioxide levels in the bag. It can’t do the job of a barrier film, which keeps moisture and oxygen from seeping in through the walls of the packaging. It also can’t make up for an inefficient shipping plan that has your coffee lingering in transit long enough that the film and seals lose their effectiveness.

While the degassing valve is very good at the job it’s designed to do, roasters shouldn’t view it as a freshness guarantee. You have to look at your packaging through a holistic lens with different features designed for different jobs.

Your bag should be designed to work as a system. Barrier films resilient enough to keep contaminants out in transit and on the shelf. Reseal features that ensure your customer’s second and third cups are just as fresh as their first. Sustainable materials that uphold brand values while allowing for a degassing valve should you need one. And flexible format options consistent enough to carry your offering across different serving styles and grocery aisles. Each of these considerations add up to the right packaging to keep your coffee fresh and your brand well represented.

How to bring it together.

Even now that you understand all the variables that determine whether or not your coffee product needs a degassing valve, it’s not entirely on you to make the final call. Your packaging partner will work through the details, help you choose the right format and materials, and ensure every aspect of your packaging protects the integrity of your product.