Tomato Juice

Why does most airline food taste bad? And what doesn’t?

Tomato juice is one of the most popular drinks served by flight attendants, yet how often do you see someone drinking the red beverage with two feet planted firmly on the ground? The question of why people find tomato juice so satisfying 35,000 feet up in the air has baffled airlines and scientists alike for years.

What’s more — aeroplane food generally tastes incredibly bland. We can never get enough of salt, spice or just any flavour! So why does tomato juice taste better while other foods taste worse? It might sound crazy, but do our taste buds get bent so out of shape during a flight that our perception of taste changes?

To find out, we need a quick lesson on how we taste our food.

Most of us know that we have five basic tastes: sweet, sour, salty, bitter, and umami. Often the least recognised, umami can be described as savoury, or meaty. Think of foods like soy sauce, mushrooms, and gravies. These five tastes all have dedicated receptors in our mouth that can communicate with our brain while we’re eating. Essentially, a tastant binds to its specialised receptor, sort of like a lock and key. The receptor is connected to a nerve ending that sends a signal to the brain, allowing us to differentiate the various tastes we’re experiencing.

Flavour is a bit more complex than taste because it’s a combination of our sense of smell and taste. In addition to the taste receptors in the mouth, our nose also has receptors for aromas. As we eat, odourants are released from the food into the air. These molecules find their way into our nasal cavity, and bind to receptors there. In fact, scientists now believe that up to 80 percent of what we taste is actually based on aroma alone.

So, how could our perception of tastes and flavours get so off-kilter in the sky?

Lufthansa, one of Germany’s biggest airlines, had the same question, and its actions illustrate just how desperate aviation companies are to fix their reputation for having drab food.

No joke, Lufthansa and its catering company literally chopped a plane up and dumped it in a cow pasture next to the Fraunhofer Institute for Building Physics.

Once there, the airline brought in physicists who equipped the grounded plane to simulate real flying conditions — the low pressure that’s responsible for making your ears pop, vibrations on each seat that mimic turbulence, and jet noise being piped in for the full experience. To top things off, they got a special setup of dry air circulating throughout the cabin.

In short, they took care, in this experimental airliner, to imitate every annoyance of the real flying experience.

Lufthansa put in all this work just to try and understand why our taste buds act so strangely during flights. Here’s what it boiled down to: dry air.

Just like the experimental aeroplane, real planes have extremely dry air circulating within their cabins. Such dry conditions actually cause physiological changes in our body during flight. Have you ever felt your skin, nose or mouth dry after flying? It’s not just the cabin air: we get dehydrated too. Our saliva diminishes and our nasal mucus evaporates.

At high altitudes, the air is much colder and not capable of holding as much moisture as warmer air. When the plane pumps this air into the cabin, it lowers the humidity level to about 10 to 20 percent — lower than that of the Sahara Desert! The end result is fewer water molecules within us and our surroundings, and water typically aids in interactions between our taste receptors and flavour molecules.

Lufthansa found that, under these dry conditions, taste perception of sweet and salty flavours was reduced by 30 percent. Imagine having to add 30 percent more sugar or salt to each dish just to make sure people can perceive the flavour. Talk about excess calories and unhealthy meals!

However, the researchers found that there were barely any changes in the ability to taste sour, bitter, or spicy flavours. These tastes were recognized just as well under control conditions and the uncomfortable, simulated flight environment.

As it turns out, airline companies aren’t the only ones interested in understanding changes to our taste perception at high altitude. In fact, several academics have also taken a stab at explaining the tomato juice paradox.

Back in 1997, researchers recruited a group of people to spend three weeks at altitudes of 3.5 kilometres, or about 11,000 feet. (Just for comparison, that’s four times the height of the Burj Khalifa). Their idea was that remaining at high altitudes, and for such a long time at that, would alter peoples’ taste perception. To test this, participants tasted the same foods before their three-week adventure and during their time at high altitudes.

When the results came, everyone was intrigued. People were suddenly better able to to identify bitter and sour flavours. At the same time, they had trouble even detecting things that were sweet or salty.

The elevation had done a real number on their taste buds.

Another study attributed our reduced sense of taste to the extreme noise levels that are experienced during flight.

On a scale of loudness, flights are typically around 85 decibels. This is comparable to a noisy restaurant or heavy traffic…which sounds reasonable, but as it turns out, any noise above 90 decibels is considered dangerous and your ears should be protected. Aeroplanes, and our daily traffic, are just about staying below the danger zone!

When panelists ate in an environment that mimicked the noise levels of an airline cabin, their ability to taste sweetness was significantly diminished, just like Lufthansa said. Interestingly, the raucous surroundings actually heightened people’s perception of umami flavours.

It seems like noise and height doesn’t reduce our ability to taste things. It does something more subtle: adjusting the intensities at which we taste different flavours.

So where does tomato juice fit into all this? Well, it’s due to our enhanced sensitivity to umami at high altitudes that tomato juice tastes this good. Tomatoes are packed with glutamates, the type of molecules that trigger our umami receptors on our taste buds. This accentuates the meaty and earthy flavours of tomato juice during flight.

The next time you hop on a aeroplane, remember: Don’t waste your free drink during the flight on soda, apple, or orange juice. Your taste buds will have a hard time even registering the sweetness.

Instead, give them what they want: tomato juice.