Coffee pods: what is the extent of their shelf life?

Once considered “glorified instant coffees”, coffee pods have become increasingly popular thanks to their convenience and accessibility.

Coffee pods are no longer the exclusive product of large-scale brands such as Keurig and Nestlé: with the global coffee pod market estimated to reach $29.2 billion by 2025, more specialty coffee roasters are venturing into the sector.

However, one of the main questions is how to preserve the coffee’s quality. Roasters must adapt their packaging process and materials to ensure their coffee pods retain freshness until the point of consumption.

Read on to find out more about the shelf life of coffee pods.

Why are coffee pods popular?

Coffee pods are single-serve doses of coffee hermetically sealed into a small capsule, which are then used with a compatible machine to make coffee.

The first company to launch coffee pods was Swiss espresso machine manufacturer Nespresso. Initially, their machines and capsules were marketed as a luxury product, targeted at hotels, bars, and offices.

When that failed to catch on, they switched to high-end consumers and made the coffee pods more affordable. By the 1990s, coffee pod culture was picking up in the domestic market.

Then, in 1998, Keurig (then trading as Green Mountain Coffee) launched their own coffee pods, which they called “K-cups”.

By 2017, the coffee pod market was worth an estimated $15.23 billion, with Nespresso alone bringing in over $4 billion. This incredible growth in popularity is largely attributed to the convenience of capsule machines and the appeal of making café-style beverages at home.

A Nespresso machine can heat water and brew your coffee within one minute.

Extraction occurs when hot water is forced through the coffee pod under pressure, in a similar fashion to a traditional espresso machine.

However, the main challenge in preserving quality in a coffee pod is trying to keep freshness locked into the beans.

Why is freshness important?

Undeniably, “freshness” is one of the defining qualities of specialty coffee.

Freshness is best defined as coffee with its original unimpaired qualities. Essentially, it is understood as coffee that has been “freshly roasted, ground within a few days, and immediately extracted and consumed”.

Despite the pivotal role of freshness in specialty coffee, the scientific measurement has been vague and elusive.

However, recent efforts by the Coffee Excellence Centre at the Zurich University of Applied Sciences have delved into what “fresh coffee” really means.

During the roasting process, carbohydrates break down and release large amounts of carbon dioxide (CO2), water vapour, and other compounds.

While much of the CO2 escapes during this process, a good quantity is stored inside the roasted coffee beans. This CO2 is gradually lost through “degassing” from the whole beans, while a substantial amount is lost during grinding and extraction.

However, as long as CO2 is present in the beans, it can help preserve freshness and delay oxidation.

Oxidation is the process by which oxygen replaces the escaped CO2, causing a loss of aroma and staling lipids. This accounts for the rancid taste often found in “old” or stale coffee.

Another way to measure the freshness of coffee is through gas chromatography. This refers to ‌separating and analysing compounds that can be vaporised without decomposition.

Additionally, specialist equipment can be used to analyse the amount of CO2 still present in roasted coffee. As it ages or becomes less fresh, there will be less CO2 in the coffee.

A further freshness index is the relative amount of two volatile aroma compounds which increase and decrease respective to one another as roasted coffee ages.

With careful aromatic analysis, levels of methanethiol can be plotted against levels of dimethyl disulfide.

Methanethiol is a highly unstable compound found in much higher levels in fresh coffee, while dimethyl disulfide is formed by two reacting molecules of methanethiol as coffee ages. This ratio is a clear indication of aromatic degradation.

Typically, coffee loses the majority of its freshness when it is ground. Depending on the age of the coffee and the grind setting, between 50% to 70% of CO2 is lost when roasted coffee is ground.

This rapid release can pose a problem for products that rely on ready-ground coffee, such as single-serve coffee pods.

What is the shelf life of coffee pods?

In most cases, the ground coffee inside pods will not be as fresh as grinding whole beans at home.

Recent research suggests at around 5% residual oxygen, coffee grounds will go stale in just a few days.

However, modern materials and practices have brought down the residual oxygen in ground coffee to about 1%. Specifically, nitrogen flushing can create a modified atmosphere inside the pods that can preserve the coffee for as long as six months.

There is speculation that flushing coffee with heavier gases, such as argon, may be a good option for removing more residual oxygen before sealing – but this is not yet widely available.

Nespresso suggests its capsules should be consumed within nine months, but there should be no harmful effects if they are used after this date – provided the seal is intact.

If there is resistance when you use a finger to push the foil membrane on a coffee pod, it is likely the seal is still good, and the coffee can be consumed.

It is important to note that moisture, heat exposure, physical damage, and oxidation can prematurely spoil a coffee pod.

Therefore, it is worth investing in sturdy packaging solutions to protect your products, and taking time to advise customers about better storage practices.

Studies show aluminium pods tend to offer the best barrier properties, as they are impermeable and protect the coffee from a loss of aroma. Additionally, they are 100% recyclable.

For specialty coffee roasters who produce their own capsules, it is essential to minimise the time between grinding the coffee and hermetically sealing the pods. It is at this point that coffee is at risk of oxidation and losing aroma compounds.

The team at MTPak Coffee specialises in providing the best quality protection for your coffee at the smallest environmental cost. Our sustainable coffee packaging line features a number of different materials that are all renewable and environmentally friendly.

Our recyclable packaging solutions can help extend the shelf life of your coffee by preserving its aroma and flavour for longer.