Best cup of coffee

Nitrogen: In pursuit of the best cup of coffee

September 25, 2020

Coffee
From bean to cup, the fate of coffee is tied up with nitrogen. While nitrogen is critical to the growth of the coffee plant, it is also the answer to the quest for preserving its freshness and quality through storage and packaging. In fact, our first encounter would have been with beans or grinds that came right of a package to make your cup. By then we were already familiar with names such as espresso and its multiple variations. Connoisseurs may have an eye out for the brewing methods and may even prefer to grind and brew their own coffee at home. But everything starts with the bean – the popular varieties (species) being Arabica and Robusta. Arabica is the more popular of the two on account of being smoother and sweeter. Whether you choose Arabica, Robusta, or a blend of both, the battle for the coffee manufacturer is to preserve freshness and character, thereby ensuring the best cup of coffee. This starts at the factory.

The battle to keep out oxygen

Roasting transforms the green beans into the aromatic brown beans we recognise. While this stage unlocks coffee’s power and flavour, it also leaves it vulnerable to its number one threat: oxygen. This happens due to a process known as degassing where the pressure resulting from the heat forces carbon dioxide to be released from within the coffee beans. Since this could cause packages to explode, many roasters allow the beans to rest in airtight silos for a while. Here the degassing process is sometimes assisted by nitrogen (added from the bottom of the storage tank to create a continuous blanket) which joins forces with CO2 to keep out the O2.

The next step in pursuit of the best cup of coffee is to put the roasted beans through the grinder. This is what determines the main categories of brew, with the coarse grind used for the French press and extra fine for the espresso machine. Grinding has the effect of releasing even more of the trapped CO2 and aromas, which is why it is usually brewed or packaged shortly thereafter. Whether it’s the roasted and rested coffee beans that are being packaged or the ground coffee, the packaging needs to deal with some gaseous realities namely: the coffee will continue to give out CO2 while sitting in the packaging. This means that there’s a good chance of the package exploding. If only there could be some way of letting out the CO2 without letting in the O2. This is where nitrogen and one-way valves pay a role.

Nitrogen flushing

Using MAP (Modified Atmosphere Packaging), the existing air is evacuated and replaced by food-grade nitrogen (a process known as nitrogen flushing) while the package is being filled with coffee, and before it is sealed. Nitrogen not only displaces any residual oxygen but being inert, keeps the coffee fresh, moreover the increased pressure in the package also has the effect of slowing down degassing. While some packaging might stop right there, speciality brands go further by placing a one-way valve in the packaging. This valve allows the CO2 to escape while keeping out the O2.

Of course, not all manufactures opt for nitrogen flushing with a one-way seal integrated into the packaging. Some packaging involves simple bagging the coffee without nitrogen flushing, especially when the contents are expected to be used within a week. Vacuum packaging which involves drawing out the air from the filled package before sealing, is another option as are metal and glass cans. Capsule packages are made for those who use coffee pod filling machines like the K-Cup. Nitrogen flushing is used in packaging such coffee pods as it serves to lower O2 levels and stretch its shelf life. Let’s not forget the increasingly popular nitro cold brew coffee that requires infusing nitrogen into coffee at high pressure to achieve a pleasant mouthfeel.

Onsite nitrogen generation

With nitrogen playing a big role in achieving consistent high-quality for the best cup of coffee, specialist coffee manufacturers and even baristas that serve nitro cold brews, depend on a regular supply of high-quality, food-grade nitrogen. In fact, European directive requires a purity level >99% for nitrogen that comes into contact with anything meant for human consumption.

Rather than depending on third parties supplying high-pressure bottles or nitrogen tanks, coffee manufacturers have seen the benefits of generating their own nitrogen on-site.

The advantages are clear:

  • No wait-time: It ensures nitrogen supply is always ready.
  • Safety: It cuts the risks associated with moving high-pressure cylinders.
  • Purity for purpose: It gives you total control over the purity of the nitrogen produced.
  • Lower cost: Operating costs are low and the investment pays off quickly.

Have you tried onsite nitrogen generation for your coffee business? Pneumatech makes it possible for you to produce all the nitrogen you need in-house with nitrogen generators that use Pressure Swing Adsorption (PSA) technology and membrane technology. Know more about how Pneumatech gas generators can work for your coffee business.