A winning combination: Recyclable degassing valves & compostable bags

Pavel Corena
June 22, 2023
An image of a recyclable degassing valve in a compostable coffee bag in an article about Recyclable degassing valves & compostable bags

Perfecting the art of coffee roasting takes a tremendous amount of time, effort, and hard work. Once this is achieved, roasters must then ensure consumers can enjoy the coffee at home or in cafes, regardless of how long it takes to reach them. This is where coffee packaging comes into play. 

By investing in the right materials and features, roasters can preserve their coffee’s aroma and flavour characteristics long enough for consumers to experience them as intended. Degassing valves are one of the key elements used to maintain the freshness of coffee, allowing roasters to opt for multilayer coffee pouches. 

That said, a growing number of businesses are investing in sustainable packaging options as governments increase restrictions on non-recyclable plastics. A large percentage of these investments focus on compostable packaging materials, such as coffee bags made using kraft paper or polylactic acid (PLA).

So, will fitting degassing valves into compostable coffee bags affect how they break down? And, if so, how can roasters ensure consumers dispose of them correctly? To learn more about using degassing valves in compostable coffee bags, I spoke with Charles Zollinger, the co-owner of Cardinal Coffee Roasters.

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The importance of the degassing process in coffee freshness

During a coffee roast, a significant amount of carbon dioxide (CO2) builds up within the bean. That CO2 slowly releases as the coffee ages in a process known as ‘degassing’. The degassing process continues throughout a coffee’s packaging, grinding, and consumption. For example, 26% and 59% of the coffee’s CO2 is released after grinding for coarse, medium, and fine grind sizes, respectively.

When roast coffee is stored insufficiently, the CO2 is replaced by oxygen, which results in a degradation of flavour. While CO2 in roasted coffee prevents it from tasting flat and stale when brewed, too much will have a negative effect on extraction. 

An interesting demonstration of the amount of gas trapped within coffee beans is the blooming process. Blooming refers to the process of pouring water over ground coffee to trigger the release of CO2 to facilitate the extraction process. Several small bubbles should appear when freshly roasted coffee is brewed. Older beans may produce significantly less bloom, as the CO2 has been replaced with oxygen.

Essentially, the one-way degassing valve was patented in 1960 to combat this problem. When fitted into coffee bags, degassing valves allow for the CO2 to leave the packaging without allowing oxygen to enter.

“We use degassing valves because we package our coffee immediately after roasting,” Charles explains. “The pressure of the build-up of CO2 could cause the bag to burst, which is exactly what we’re trying to avoid. It’s also an effective feature that helps consumers smell the product – at least, that’s what I do when I buy a competitor’s coffee.”

An image of a Cardinal Coffee Roaster coffee bag, customised coffee packaging, custom-printed coffee bags with recyclable degassing valves, in an article on recyclable degassing valves & compostable bags

The rise of sustainable degassing valves

Typically, degassing valves consist of five pieces, including a cap, an elastic disc, an adhesive layer, a polyethylene plate, and a paper filter. A rubber diaphragm is enclosed in a valve and the interior, or coffee-facing part of the diaphragm has a viscous layer of sealant liquid. This is what helps maintain surface tension against the valve.

Pressure builds up as coffee degasses and releases CO2. Once the pressure inside the roasted coffee bag passes the surface tension, the fluid will displace the diaphragm, allowing the excess CO2 to escape. The valves can be visible from the outside of the bag or hidden within the layers of packaging. Furthermore, they can be placed on almost any coffee bag structure with a heated application process that is unlikely to compromise the seal on existing packaging. 

The majority of traditional degassing valves are made using polyethylene (PE): the most widely used plastic in the world. This is important to note, as recent reports show consumer demand for sustainable packaging has risen to 81%.

In turn, this has driven the demand for more sustainable degassing valves that can be used and disposed of alongside their packaging counterparts. Over time, flexible degassing valves have gradually replaced hard button valves. These valves use 90% less plastic, resulting in a lower price and reduced environmental impact. 

While these are better for the planet, they’re still made of plastic. Even if the rest of the packaging is compostable or biodegradable, consumers must remove the valve before disposing of the rest of the packaging as indicated. As a result, a popular choice is recyclable degassing valves, which are produced using injection-moulded bioplastics made from renewable resources, such as crops.

Recyclable degassing valves have the same properties as plastics without the environmental impact. They can help conserve fossil fuels, reduce a brand’s carbon footprint, and communicate a commitment to sustainability. Furthermore, they allow customers to dispose of coffee packaging with minimal confusion.

An image of Cardinal Coffee packaging, compostable coffee bags with recyclable degassing valves on a wooden shelf in an article on recyclable degassing valves & compostable bags

A winning combination: Recyclable degassing valves & compostable coffee bags

Adding recyclable degassing valves to sustainable packaging materials, such as kraft paper with polylactic acid (PLA) laminate, allows roasters to offer a fully sustainable coffee pouch. As well as providing an attractive option for new customers, this can help boost brand loyalty among existing customers who might otherwise have switched their allegiance to more sustainable competitors.

“Cardinal Coffee chose to invest in compostable coffee packaging materials because we feel it is one of the most ethically responsible routes,” Charles says. “I understand compostable packaging costs more, but it shouldn’t always be about making maximum profits. I hate to see plastic thrown away, so our coffee bags compost naturally in refuse.” 

Compostable coffee bags are made from organic matter that breaks down to produce nutrient-rich compost and leaves no environmentally damaging residue. This form of coffee packaging is sturdy, affordable, and easy to produce, and allows roasters to showcase their commitment to sustainability. MTPak Coffee understands the importance of providing consumers with high quality, freshly roasted coffee in eco-friendly packaging. This is why we offer fully recyclable, BPA-free degassing valves that use a nylon filter valve. This means they are able to retain membrane integrity without cracking, tearing, curling, or breaking.

Recyclable degassing valves can be used to create a user-friendly product for consumers and reduce the negative environmental impact of coffee packaging. The valves can be removed from coffee bags and placed in consumers recycling bins, ensuring they are disposed of correctly. In addition to being versatile, lightweight, and affordable, our valves can be fitted to our entire range of sustainable coffee packaging options.

Our sustainable coffee bags are made using kraft paper, rice paper, or multilayer LDPE packaging with an environmentally friendly PLA lining, while our coffee boxes are made using recycled cardboard. Our eco-friendly customisation techniques include spot UV with a glossy, satin, or matte finish, embossing and debossing, as well as hot foil stamping in a variety of colours.

Contact our team to learn more about compostable coffee packaging and recyclable degassing valves.

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