December 22, 2023

Why do we nitrogen-flush our private label coffee capsules?

We know that the fresher coffee is, the better it tastes. But keeping coffee fresh isn’t always simple – there are several factors that cause it to lose its desirable traits. 

This is true for any form of coffee – including the grounds inside private label coffee capsules. If you maximize the freshness of the coffee inside, you preserve its original flavor and aroma characteristics.

Here at Metropolis, we use nitrogen flushing to give our espresso capsules an extended shelf life. This ensures your coffee capsules retain optimal quality until you're ready to brew them. But why do we use nitrogen, and how does the process work? Read on to find out.

A shot of espresso prepared using private label coffee capsules.

Why is coffee freshness important?

Fresh coffee tastes better. Over time, the more complex flavors and nuances in coffee gradually fade, causing it to stale. But why does this happen?

Green coffee is a non-volatile food product. When you roast it, it becomes volatile, meaning that exposure to certain factors can cause it to lose its flavor and aroma characteristics. These factors include light, heat, moisture – and, most importantly, oxygen.

Roasting also causes carbon dioxide (CO2) to form inside coffee beans. After roasting, the beans immediately begin to release CO2 in a process called “degassing”. Most of the gas dissipates within the first few days after roasting. It’s actually better to leave the coffee to rest after it’s roasted to ensure that enough CO2 has been released – meaning it doesn’t taste bitter and astringent.

However, as the CO2 escapes, it opens up space for oxygen to creep in. Over time, the coffee will oxidate, losing freshness in the process. If you store freshly roasted whole beans in an airtight bag, they can stay fresh for between six months to one year. 

Unfortunately, ground coffee doesn't last as long. It has a much larger surface area, making it more vulnerable to oxidation. That’s why roasters and baristas recommend grinding just before brewing.

Furthermore, the finer you grind, the higher the surface area – and the quicker coffee turns stale. This is especially important for private label coffee capsules – which contain very finely ground coffee.

Nitrogen flushing private label coffee capsules at a factory.

What is nitrogen flushing?

Nitrogen flushing uses nitrogen gas to force oxygen out of food product packaging. Manufacturers use it to prevent oxidation, keeping the airtight product fresher for longer. 

We use a state-of-the-art Italian filling and sealing system to meticulously fill, seal and nitrogen-flush our private label coffee capsules. Nitrogen is heavier than oxygen, so it sinks to the bottom of the capsule and forces oxygen out. 

Manufacturers aim to keep oxygen levels inside coffee capsules below 1%. After flushing, the capsules are sealed hermetically to keep oxygen out – extending the capsule’s shelf life.

Studies have confirmed the effectiveness of nitrogen flushing, showing that nitrogen-flushed coffee typically has a shelf life twice as long as non-flushed coffee. The same applies to private label coffee capsules.

Generally, roasters encourage customers to enjoy nitrogen-flushed coffee within seven to ten days of opening the bag. Once you break the seal, there’s no going back, meaning the coffee will gradually turn stale over time. However, nitrogen-flushed coffee capsules remain sealed and fresh until you’re ready to brew them.

It’s the perfect way to offer your customers fresh, high-quality specialty coffee without compromising on convenience. All you need to do is store them in a cool, dry and dark place to best preserve their freshness and quality.

A filling machine at the Metropolis factory in Chicago.

Metropolis private label coffee capsules

At Metropolis, we believe that nitrogen flushing is the best way to keep coffee capsules fresher for longer. Research shows that this doubles the average shelf life of a coffee capsule. However, it’s a complicated process requiring specialized equipment.

That’s why for most businesses, it’s simply too costly and time-consuming to navigate the complexities of coffee capsule manufacturing. In fact, it’s impossible to manufacture them without exactly the right setup.

That’s where we come in. Through our private label coffee capsule service, businesses like hotels, restaurants and cafés can offer their very own coffee capsules. 

Private label coffee capsules are custom capsules manufactured by a wholesale coffee roaster on behalf of other businesses. That means you don’t need any of the infrastructure, expertise, or equipment to do it yourself. 

How does the private label coffee capsule service work?

It’s simple. Send us an inquiry and we’ll work with you to develop the right product for your business, whether it’s a specific flavor profile or an eye-catching packaging design.

For a start, we offer four award-winning blends in capsule form or we can work with your coffee instead!

Once you decide on a coffee, we grind it to the perfect size for capsule extraction using a commercial roller mill. Then we fill, seal and nitrogen flush the capsules using our state-of-the-art facility and equipment. 

Finally, we package the finished espresso capsules in boxes with your branding. We can also secure globally recognized certifications like organic and Fairtrade. 

Plus, our private label coffee capsules are commercially compostable and certified by the Biodegradable Products Institute (BPI) and the Composter Manufacturing Alliance (CMA). These certifications mean that our capsules meet the strictest composting standards in the US, so you can dispose of them at any commercial composting in the US.

Interested in learning more? Check out our wholesale co-packing and private-label espresso capsule solutions today.

Certified compostable facilities may not exist in your area. To find a composter near you, visit or on all packaging and marketing materials.

Metropolis Coffee is not affiliated with, endorsed, or sponsored by Nespresso. Nespresso is a registered trademark of Société des Produits Nestlé.

Metropolis Coffee

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