“Somewhere above the clouds, even flavour loses its footing. At 34,000 feet, the meal may be the same, but the sky quietly changes the way we experience it.” – MJ Martin
On today’s flight, I discussed the taste difference for food while eating on airplanes with the In-charge Flight Attendant. He raised some fascinating points that got me thinking. So I decided to investigate the facts from the fiction. Here is what I learned.
You Are Flying at 34,000 Feet, but Your Taste Buds Think You Are on a Mountain
For Canadians travelling across our enormous country, eating lunch while cruising somewhere over Saskatchewan at 34,000 feet may seem perfectly ordinary. Physiologically, however, your body knows that something unusual is happening.
Although the aircraft may be flying at 34,000 feet, the passenger cabin is pressurized. Canadian airworthiness standards normally require a cabin pressure altitude of no more than 8,000 feet. You are therefore not experiencing the atmosphere outside the aircraft, but neither are you experiencing sea-level conditions.
Think of the cabin as an artificial mountain lodge moving at 800 kilometres per hour. The lower pressure, extremely dry environment, and continuous background noise combine to change how food and beverages are perceived.
Taste Is Only Half the Story
What we casually call “taste” is actually flavour, and flavour is produced by several senses working together. Your tongue detects basic tastes such as sweet, salty, sour, bitter, and umami, while your nose supplies much of the detailed information that distinguishes coffee from chocolate, or Coke from Pepsi.
Reduced cabin pressure alters this sensory system. Fraunhofer Institute researchers using a simulated aircraft cabin found that saltiness was perceived approximately 20 to 30 percent less intensely, while sweetness declined by roughly 15 to 20 percent. Fruity aromas and acidic sensations were considerably more stable.
The effect is somewhat like eating dinner while suffering from a mild head cold. The food has not changed nearly as much as your ability to perceive it has.
The Roar of the Cabin Is Changing Your Dinner
There is another surprisingly important factor: noise. A commercial aircraft cabin can expose passengers to substantial continuous background sound. Cornell University researchers found that loud aircraft-like noise suppressed perceived sweetness while increasing the perceived intensity of umami, the savoury quality associated with foods such as tomatoes. A peer-reviewed review of airline food research likewise identifies reduced pressure, low humidity, and background noise as three major influences on flavour perception in flight.
This helps explain why strongly flavoured foods, tomato juice, sauces, curries, herbs, and savoury dishes can perform particularly well aboard aircraft.
Why Everyone Suddenly Wants the Salt and Pepper
My Flight Attendant’s observation about seasoning is therefore well supported. Because saltiness is weakened considerably, food prepared to taste perfect in a Toronto restaurant kitchen may seem bland somewhere above Manitoba. Airline caterers compensate by designing recipes specifically for the cabin environment. Fraunhofer’s aircraft-cabin experiments found that mild foods such as fish and poultry often required stronger seasoning, herbs, or other flavour enhancers.
The salt shaker is effectively turning up the volume on a sensory signal that the aircraft environment has turned down.
Coke or Pepsi? At Altitude, the Difference May Shrink
The suggestion that passengers cannot distinguish Coke from Pepsi at altitude is entertaining, but it should not be presented as established scientific fact. Air Canada recently stopped serving Coke and switched to Pepsi. Much to my personal disappointment. My Flight Attendant offered that the taste differences are minor while at altitude. I could find no controlled study demonstrating that people lose the ability to distinguish those two specific drinks in an aircraft cabin.
Coke and Pepsi may belong to the same cola family, but they do not taste identical. Pepsi is generally perceived as slightly sweeter, with a brighter citrus character and a softer finish, while Coca-Cola is often described as having a sharper initial bite, more pronounced caramel, vanilla, and spice notes, and a drier finish. Carbonation also plays a role because the sensation of dissolved carbon dioxide contributes acidity, aroma release, and the familiar “bite” of a cola. In a blind sip test on the ground, those differences can be noticeable, especially to someone who regularly drinks one brand. At cruising altitude, however, reduced sweetness perception, diminished aroma sensitivity, dry cabin air, and continuous aircraft noise can compress those differences. The two drinks do not suddenly become chemically identical, but the sensory distance between them may feel smaller, much like turning down the contrast on a photograph until two similar shades become harder to distinguish.
What science does support is more nuanced. Since sweetness and aroma perception are diminished, some of the sensory differences between two colas may become less obvious. However, acidity and some aromatic characteristics remain comparatively resilient. Individual passengers could therefore still distinguish them, particularly people familiar with both products.
So, is my Flight Attendant wrong? Not entirely. Flying genuinely changes flavour perception, sometimes dramatically. But saying Coke and Pepsi become indistinguishable turns a fascinating piece of sensory science into airline folklore.
Your Meal Has Not Changed. You Have.
So, the conclusion is that the meal has not changed at all. But you and your senses of taste and smell have changed. So the perception is that the food has changed. The especially striking finding is the magnitude of change. A 20 to 30 percent reduction in perceived saltiness is large enough that the same meal can genuinely seem under-seasoned in the air even though its chemistry has not changed.
Questions to Ponder
The interesting questions are broader.
- Should airlines deliberately formulate meals with more salt when Canadians are already encouraged to limit sodium?
- Could umami, herbs, spices, and acidity produce better-tasting meals without simply adding salt?
- And if you conducted a blind Coke-versus-Pepsi test on the ground and repeated it at cruising altitude, would your own palate prove the flight attendant right?
About the Author:
Michael Martin is the Vice President of Technology with Metercor Inc., a Smart Meter, IoT, and Smart City systems integrator based in Canada. He has more than 40 years of experience in systems design for applications that use broadband networks, optical fibre, wireless, and digital communications technologies. He is a business and technology consultant. He was a senior executive consultant for 15 years with IBM, where he worked in the GBS Global Center of Competency for Energy and Utilities and the GTS Global Center of Excellence for Energy and Utilities. He is a founding partner and President of MICAN Communications and before that was President of Comlink Systems Limited and Ensat Broadcast Services, Inc., both divisions of Cygnal Technologies Corporation (CYN: TSX).
Martin served on the Board of Directors for TeraGo Inc (TGO: TSX) and on the Board of Directors for Avante Logixx Inc. (XX: TSX.V). He has served as a Member, SCC ISO-IEC JTC 1/SC-41 – Internet of Things and related technologies, ISO – International Organization for Standardization, and as a member of the NIST SP 500-325 Fog Computing Conceptual Model, National Institute of Standards and Technology. He served on the Board of Governors of the University of Ontario Institute of Technology (UOIT) [now Ontario Tech University] and on the Board of Advisers of five different Colleges in Ontario – Centennial College, Humber College, George Brown College, Durham College, Ryerson Polytechnic University [now Toronto Metropolitan University]. For 16 years he served on the Board of the Society of Motion Picture and Television Engineers (SMPTE), Toronto Section.
He holds three master’s degrees – in business (MBA), communication (MA), and education (MEd). As well, he has three undergraduate diplomas and seven major certifications in business, computer programming, internetworking, project management, media, photography, and communication technology. He has completed over 80 next generation MOOC (Massive Open Online Courses) [aka Micro Learning] continuous education programs in a wide variety of topics, including: Economics, Python Programming, Internet of Things, Cloud, Artificial Intelligence and Cognitive systems, Blockchain, Agile, Power BI, Big Data, Design Thinking, Security, Indigenous Canada awareness, and more.
Martin is a volunteer, a photographer, a learner, a technologist, a traveller, a pilot, a philosophizer, and a most of all, aromantic optimist.