Degassing valves in coffee bags: When are they needed?

Hayley Osbourne
March 20, 2023
An image of a custom printed coffee bag made from LDPE fitted with a recyclable degassing valve in an article on whether coffee bags need degassing valves

Many believe roasters have little control over a coffee’s freshness once it has left the roastery. 

However, there are several ways roasters can continue to preserve coffee freshness after it has left their premises. 

One such solution is to invest in high-quality packaging with effective barrier protection. To further ensure coffee freshness, many roasters also fit one-way degassing valves into their coffee bags.

The question is, do all coffee bags require degassing valves, or can roasters do without them?

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Is it essential for coffee bags to have degassing valves?

When coffee is roasted, there is a significant build-up of carbon dioxide (CO2) within the bean. 

That CO2 is slowly released as the coffee ages in a process known as degassing. Degassing 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. 

Furthermore, when roast coffee is insufficiently stored, the CO2 is replaced by oxygen, which results in a degradation of flavour. 

During the 1960s, the one-way degassing valve was patented to combat this problem. In essence, a degassing valve is made of a cap, an elastic disc, a viscous layer, a polyethylene plate, and a paper filter.

A rubber diaphragm is enclosed in a valve and the interior, or coffee-facing part, has a viscous layer of sealant liquid that maintains surface tension against the valve.

Pressure builds up as CO2 is released from coffee. Once that pressure passes the surface tension, the fluid will displace the diaphragm, allowing the excess CO2 to escape.

Therefore, a degassing valve is necessary on coffee packaging to help the gasses leave the bag and stop it from ballooning.

Degassing valves are usually included on the inside of coffee packaging with small holes on the outside to allow the CO2 to seep out. 

This provides an aesthetic look that can also be used to smell the aroma of the coffee prior to purchase.

An image of a coffee roaster holding up a bag of roast coffee in a kraft paper coffee bag with a PLA lining and a recyclable degassing valve in an article on whether coffee bags need degassing valves

When are degassing valves needed in coffee bags?

In recent years, the use of one-way degassing valves has become one of the most crucial preventative measures to help preserve valuable volatiles and reduce the oxidation process of coffee.

That said, a roaster’s decision to use a degassing valve can hinge on many factors. These include the roast profile and whether they are selling whole beans or ground coffee.

For example, darker roasts often degas at a quicker rate than light roasts, despite having a higher buildup of gases. This is because the structure of the beans becomes more porous the longer they spend in the roaster.

A key point is for roasters to understand their customers’ consumption preferences. This will help determine the average size of the packaged coffee, as well as the order volumes required.

While degassing valves have revolutionised the way coffee is packaged, there are many reasons ‌roasters may not want to use one.

The most obvious one is that it adds to packaging costs. Additionally, some roasters are concerned that valves accelerate the loss of aromatics. They found sealing a bag without a valve may cause it to expand and puff up, but it does not explode.

As a result, these roasters often choose to vacuum seal their coffee instead. Vacuum sealing and nitrogen flushing are two of the most effective ways of preserving roasted coffee.

Both packing methods greatly reduce oxidation and slow the rate of staling, helping to keep coffee fresh for weeks, if not months, on end.

That said, the use of one-way degassing valves in coffee packaging will be determined by certain factors, such as the volume of coffee being packaged, and whether the coffee is ground or whole-bean.

An image of roast coffee in a LDPE custom printed coffee bag with a resealable zipper and recyclable degassing valve in an article on whether coffee bags need degassing valves

Sustainable degassing valves are growing in popularity

The demand for sustainable packaging has increased substantially within the last decade.

Several studies show consumers are aware of the negative environmental impact of plastic packaging and are pushing for more sustainable alternatives.

As a result, eco-friendly packaging materials such as kraft and rice paper, polymers, and paperboard have become popular within the food and beverage industries.

More roasters are using coffee packaging made from bioplastics, such as polylactic acid (PLA) and recyclable plastics like low-density polyethylene (LDPE).

More so, water-based inks and environmentally friendly adhesives have also been developed in order to create eco-conscious packaging consumers can dispose of easily.

Therefore, investing in sustainable degassing valves could be highly beneficial for any coffee business.

Sustainable degassing valves are 100% recyclable alternatives to older models. Traditionally, if a coffee bag was made with recyclable materials, a person had to remove the degassing valve before recycling the bag.

This was because older degassing valves were commonly made using plastic and other non-recyclable materials.

However, recyclable degassing valves are made using injection-moulded bioplastics, which provide the same properties as plastic valves.

These may help a coffee brand appeal to consumers concerned with their carbon footprint as it allows them to dispose of their used coffee bags without confusion.

At MTPak Coffee, we offer roasters the option to fit their coffee bags with fully recyclable, BPA-free degassing valves.

In addition to being versatile, lightweight, and affordable, our valves can be fitted to our entire range of sustainable coffee packaging options.

Roasters can choose from renewable materials such as kraft paper, rice paper, or multilayer LDPE packaging with an environmentally friendly PLA lining, all of which minimise waste and contribute to a circular economy.

Our design team is available to help you create the ideal coffee packaging.

Plus, we are able to custom-print coffee bags using innovative digital printing technology, with a quick turnaround time of 40-hours and 24-hour shipping time. 

MTPak Coffee also offers low minimum order quantities (MOQs) to micro-roasters who are looking to remain agile while showcasing brand identity and a commitment to the environment.

For more information on our recyclable degassing valves, contact our team.

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