For specialty roasters, there are a number of variables to consider when deciding on coffee packaging, from colour and shape, to materials and additional components. However, one variable that’s often overlooked is size.
The size of packaging can have a considerable influence not only on the freshness of coffee, but also on its distinct characteristics, including aroma and flavour notes. Crucial to this is the amount of space around the coffee when it’s packaged, otherwise known as “headspace”.
To find out more about the importance of coffee packaging sizes, I spoke with Head of Training at Australia-based ONA Coffee and 2017 World Barista Championship finalist, Hugh Kelly.
Headspace: What is it and how does it affect freshness?
With the exception of vacuum-packed coffee, the vast majority of flexible packaging comes with an empty air-filled area above the product, commonly known as “headspace”.
As well as serving to protect the coffee by creating a cushion around the beans, headspace is essential in preserving freshness and maintaining a coffee’s characteristics. As three-time Australia Barista Champion Hugh Kelly tells me, “roasters should always know how much space is above the coffee inside the bag”.
The reason for this is due to the release of carbon dioxide (CO2). When coffee is roasted, CO2 builds up in the porous structure of the beans before gradually releasing in the days and weeks that follow. The level of CO2 in coffee can affect everything from its aroma to its flavour notes.
When coffee is packaged, it needs a certain amount of headspace in which the released CO2 can sit and create a carbon-rich environment. This helps maintain the pressure between the beans and the air inside the bag, creating an equilibrium that prevents further diffusion.
If, on the other hand, all the CO2 were to immediately escape from the bag, the coffee would degrade quickly and its shelf life would reduce significantly.
However, there’s an optimum. Hugh explains some of the changes that can occur to a coffee’s characteristics when packaging headspace is too small: “If headspace is too tight and gas from the coffee is heavily compacted around the beans, it can negatively affect the quality of the coffee,” he says.
“It can make the coffee taste heavy, sometimes a little bit smokey. But some of this might depend on roast profile, because light roasts and fast roasts can react differently.”
The speed of the roast can also have an impact on the rate of degassing. Coffee that’s been roasted quickly tends to retain more CO2 for the simple reason that it has less time to escape during roasting.
What happens when headspace increases?
Naturally, as consumers drink their coffee, the headspace in the packaging will increase. When this happens, more gas is allowed to diffuse from the beans into the surrounding air.
Hugh tells me that to maintain freshness, consumers should reduce the headspace as and when they drink the coffee.
“Consumers need to take headspace into account,” he says. “Unless the coffee is really fresh and still producing a lot of CO2, they need to reduce the headspace to stop it diffusing any further. You can do this by squeezing the air out of the bag and taping it down.
“Conversely, if the coffee is really fresh, when consumers close the bag, it’s best to not constrict it too much because some gas still needs space to move into when it’s released from the beans.”
Reducing headspace helps minimise the amount of oxygen inside the bag, too. Each time the bag is opened, oxygen enters, which can cause the coffee to lose aroma and become stale. By squeezing the bag and minimising the amount of air surrounding the coffee, it reduces the chances of oxidation.
Choosing the right size packaging for your coffee
For specialty roasters, it’s important to ensure the headspace of their packaging is small enough to preserve freshness but large enough so as not to affect the coffee’s characteristics.
Hugh tells me while there are no hard and fast rules for the amount of headspace a coffee should have, it’s the responsibility of the roaster to carry out tests to find out what works for each of their offerings.
“For roasters, the only way to decide if the amount of headspace is appropriate for their coffee is to do side-by-side tastings,” he explains. “Every roaster is aiming for a different style of coffee, a different extraction, and different intensities.”
Conclusively, the size of packaging is dependent on the weight of beans stored inside. Larger amounts of beans for wholesale customers may require bigger packaging, such as flat bottom or side gusset pouches.
Retail coffee beans for home consumers typically weigh around 250g, therefore stand-up or quad-seal bags may be more appropriate.
“If you have a heavier coffee [with a darker] roast profile, [more] headspace might…be [beneficial because]…it [will]…lighten up [the coffee],” Hugh recommends.
However, when packaging light or medium roasts, larger headspaces may be detrimental, as Hugh explains, “It might cause [the coffee to] age…faster.”
It’s also a good idea to fit coffee pouches with degassing valves. Degassing valves are one-way vents that can be fitted to all types of packaging either during or after manufacture. They allow built-up CO2 to escape from the bag without letting oxygen in.
Despite being a relatively overlooked aspect, the size of packaging plays a fundamental role in preserving freshness and maintaining the distinct characteristics of the coffee. Too much space between the beans and the packaging will cause the coffee to become stale, while too little could impart “heavy” flavours.
At MTPak Coffee, we understand how important it is for specialty roasters to provide their customers with the best coffee possible. With our expert design services and fully customisable options, we can help you create the perfect-sized packaging for your coffee, whether whole bean or ground. We also offer fully recyclable, BPA-free degassing valves that can be fitted neatly on the inside of pouches.
To find out more information about our sustainable coffee packaging, contact our team.
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