When it comes to flavor, coffee purists prefer whole beans, which retain their flavors longer than ground coffee. Yet there’s no denying the convenience factor of ground coffee, which is why it’s so popular in offices. Ground coffee has a short shelf life — hence the push to use airtight containers, which keep the flavors in the coffee — and off flavors may develop if the coffee grounds are left on the shelf too long. Some coffee companies are trying a new trick to add shelf stability to their ground coffee: a nitrogen flush.

How Nitrogen Flushing Preserves Coffee Grounds

Oxygen is the enemy of ground coffee: When coffee grounds come into contact with oxygen, they go stale faster. This is why coffee grounds are sold in vacuum-sealed containers, and why consumers are encouraged to use airtight containers. For best flavor, coffee beans should also be stored in dark containers (so light does not pass through).

Some amount of oxygen is produced (in the form of CO₂) as the ground coffee degasses, a naturally occurring process. To release these gases and preserve coffee flavor, many coffee bags contain a one-way valve. Oxygen escapes through the valve, but cannot come back into the bag.

Some coffee companies are taking it one step further by flushing the bag with nitrogen gas during the coffee packaging process, which ensures that no oxygen is in the bag with the coffee where it would cause spoilage. Nitrogen gas is heavier than oxygen, so when it is pushed into the empty coffee bag, it displaces oxygen. The bag is then filled with coffee grounds and sealed with no ambient oxygen in the sack. This preserves coffee flavor.

Since nitrogen gas has no color or odor, it does not affect the taste of the coffee. What consumers get, months later, is grounds that are as fresh as they were the day the coffee was roasted and ground.

While this is beneficial for the consumer, nitrogen flushing may prevent problems at the packaging plant. Just as nitrogen gas flushes oxygen out of the bag, so can it displace oxygen from the room. If a leak were to occur, employees would not be able to tell (remember, the gas has no smell, odor, or color). A leak could push so much oxygen out of the air that staff could suffer respiratory problems, death via asphyxiation being the worst-case scenario.

How an Oxygen Sensor Can Protect Your Employees

Since nitrogen displaces oxygen, it’s easy to detect a leak by tracking the levels of oxygen in the room. Oxygen sensors — also known as oxygen deficiency monitors — continually monitor oxygen levels. As long as the room air remains stable, there’s no leak. When the levels of oxygen in the air fall to the OSHA threshold of 19.5 percent, where a health threat is imminent, the sensor will go off. Employees will see a flashing light and hear a loud alarm that warns of the low levels of oxygen. Staff can exit the packaging facility without suffering adverse health effects; they also enjoy peace of mind every day by checking the O₂ monitor.

PureAire supplies coffee manufacturers with oxygen sensors that help them offer a higher-quality product without placing workers at risk. PureAire’s oxygen deficiency monitor requires no maintenance and calibration once installed, thanks to a hardy zirconium sensor. Once installed, the O₂ monitor will provide accurate readouts and leak detection for 10 or more years. PureAire’s oxygen deficiency monitors function properly despite changes to barometric pressure, thunderstorms, and other weather events. Suitable for use in freezers, basements, and other confined spaces, PureAire’s monitors perform in temperatures from 55 Celsius to -40 Celsius.

To protect worker safety, an oxygen monitor should be used wherever nitrogen gas is stored or used.