Coffee is one of the most popular beverages in the world, with more than 166 million 60-kilogram bags of coffee consumed in 2021 alone. That’s over 48-billion pounds of grounds.

Finland claims the title as the most caffeinated country, with the average Finn consuming over two and half cups daily.  

Our global love affair with java – be it black, decaffeinated, espresso-based, cold-brewed or something else entirely – has drastically increased availability expectations, including at cruising altitude.

It’s the reason coffee makers are the most prevalent piece of galley equipment flying on all types of aircraft today. But making a good cup of joe onboard presents a unique set of challenges all its own.

Making a good cup

Assuming a starting point of quality beans – properly harvested, roasted and ground – correctly extracting flavor in the brewing process is critical to a quality sip. Three primary variables that must align are:

•  water temperature

• the time the water is exposed to the grounds

• the amount of agitation enacted upon the coffee during the brewing process.

This becomes much more complicated once in the air.

Brewing complications at altitude

“Brewing coffee on-board an aircraft has many implications,” says Mudar Abu-Saymeh, a senior engineering manager and research and development lead for Collins’ galley inserts – the cooking appliances used to prepare in-flight food and beverages.

For instance, the boiling point of water changes significantly at altitude, leaving a much narrower window to brew coffee at the optimum temperature without boiling the water and spoiling the cup.

“Water boils at 197°F at 8,000 feet cabin pressure, with the ultimate brewing temperature for coffee ranging between 195-205°F, depending on the coffee roast type,” says Abu-Saymeh. “So now, we only have about two degrees to play with to hit that perfect brew temperature without spoiling the drink. It’s an extremely precise line to navigate.”

To solve for the altitude complication, Collins’ coffee makers incorporate microprocessors for precision temperature control, while proprietary brew-head and brew cup designs ensure water is properly exposed and agitated by injecting water into the middle of the brew cavity and then flowing the water outward through the coffee grounds.

A pre-infusion feature temporarily pauses the brew process after injecting water to the grounds, allowing the grounds to expand before brewing resumes in what’s known as ‘blooming’, which enhances water exposure to produce optimal flavor.

Practically speaking

Abu-Saymeh’s team not only investigates and implements emerging technologies like these, but also solves for the practical challenges of on-board brewing – like size, weight, power and cooling.

Consider equipment at a coffee shop – large, heavy, made of metal and exposed to air on at least four sides to keep it cool. In other words, a luxury of space compared to what’s available on board an aircraft. What’s installed on airplanes must be a fraction of the size and weight and be self-cooling since only one side of the machine is exposed to air.

Add in inconsistent water and power supplies inherent to all aircraft – along with stringent aviation certification standards – and the sheer amount of precise engineering and technology integration needed for a coffee maker becomes a lot clearer.

The human factor

Another factor is who prepares the drink, particularly espresso-based offerings. On the ground, baristas are highly trained and focused on the operation and maintenance of those machines. Flight attendants are more multi-faceted in their duties – tasked with accommodating passenger service, safety and comfort, along with operating galley equipment.

“So, the equipment we produce is simpler, more intuitive and consistent than what you can get away with on the ground,” explains Brian Schmalz, vice president of marketing and sales for Collins’ line of galley inserts. “There’s an ergonomic, small environment and time perspective that goes beyond what you see in a coffee shop.”

A great example of this is Collins’ Nespresso® machine and the built-in automatic cappuccino function. A ground customer would expect a barista to manually adjust the time, temperature and the pitcher or steam wand to get the perfect quality of milk. Flight attendants don’t have the time or space capacity to do that.

“We’ve figured out how to make the machine do all of that itself,” says Schmalz. “Allowing the airline to offer a high-quality product without burdening their onboard resources to pull it off.”

Continuing education

And Schmalz should know a good cup of coffee. Shortly after joining Collins in 2011, he completed coursework and testing to become a certified barista, saying it gives him greater insight to the art and science of how a great cup of coffee is made.

“We were always great at designing, engineering and certifying products. Where I saw an opportunity was with the human aspect,” said Schmalz. “And it’s worked – it’s improved the end-product and how we help our customers make the best choices for their passengers.”

Many others have followed Schmalz in taking food science coursework, extending to those supporting ovens and chillers to gain a better understanding of food science and taste preferences.

Educational application

Collins’ coffee makers reflect this increased knowledge of food science with preset, software-based deviations to vary coffee strength based on varying taste preferences found around the world – giving airlines plenty of options to provide an optimal taste experience for their passengers.

Adding the human touch to science and technology development to help drive innovation – it’s a big reason Collins’ line of galley inserts are the most popular in the world.

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