You’ve heard the rumors. Maybe you’ve even experienced it yourself during a long flight when something just felt off after ordering your usual beverage. I spent 15 years serving drinks at 30,000 feet, and honestly, I’ve seen things that would make you rethink your entire in-flight beverage strategy. This isn’t about being dramatic. It’s about knowing what actually happens behind that beverage cart.
The truth is, not all drinks are created equal when you’re cruising at altitude. Some choices can leave you feeling worse than when you boarded. Let’s dive into what you really need to know about airplane beverages.
Hot Coffee or Tea Made with Tap Water
Let’s be real here. That steaming cup of coffee might smell amazing, yet what’s actually in it could surprise you. Airlines are serving potentially unhealthy water to passengers, according to research, with the nonprofit Center for Food as Medicine & Longevity examining more than 35,000 water samples served by 10 major and 11 regional airlines over three years. Of the total 35,674 samples tested, 949 came back positive for coliform, with 32 total violations for E. coli occurring across the 21-airline universe.
Here’s the thing that shocked even me when I first learned about it. The airplane water tanks are generally not refilled only when they are empty, instead they are often just topped-up between flights, and additionally the airplane water tanks are cleaned infrequently. Among major U.S. airlines, three – American Airlines, JetBlue and Spirit – earned a D rating from the group, while Delta and Frontier were the top-ranked major carriers, both earning A grades for their water.
Diet Soda or Any Carbonated Beverage
I know it sounds crazy, considering soda is offered on nearly every flight. The problem isn’t the soda itself, it’s what happens to those bubbles at altitude. Low air pressure means expansion of gasses in the gut, as air pressure decreases at higher altitudes, and the basic laws of physics dictate that gasses expand as air pressure decreases, with whatever gas in your gut as you board the plane likely to put more pressure against the bowel walls as altitudes rise.
Avoiding carbonated beverages in flight is recommended, as the bubbles in your club soda are carbon dioxide gas, which may expand in the digestive tract during flight, causing more discomfort and distension than usual. That innocent ginger ale could turn your stomach into a balloon factory. According to the Aerospace Medical Association, increased pressure can cause gases in your body cavities to expand by up to 25 percent, and when gases in your abdomen expand it can lead to discomfort and bloating.
Alcoholic Cocktails or Wine
This one catches a lot of passengers off guard. You think you’re treating yourself to a relaxing glass of wine, yet altitude has other plans. People who drank before falling asleep in the altitude chamber on average had their blood oxygen saturation drop to 85 percent, while their heart rates rose to compensate for the lower oxygen levels to an average of nearly 88 beats per minute.
The combination of drinking alcohol and sleeping while on a plane puts a big strain on the body, especially the cardiovascular system, with even more strain if someone has heart or lung disease, placing the person at a higher risk for a heart attack or stroke. Here’s the thing nobody tells you: Alcohol is a diuretic, meaning it increases urine production and can cause the body to lose more fluids, and when combined with the already dehydrating environment of an airplane cabin, drinking alcohol can lead to significant dehydration.
I’ve watched passengers order three glasses of wine during a five-hour flight and wonder why they felt terrible upon landing. The science doesn’t lie.
Ice Water from the Airplane Tap
You might think plain water is the safest bet. Think again if that water comes from the airplane’s tanks. The study analyzed 35,674 total sample locations across all airlines and found that 949 locations tested positive for total coliform bacteria, representing a 2.66 percent contamination rate, and more alarmingly the study identified 32 Maximum Contaminant Level violations for E. coli across the airline industry during the study period.
The recommendation from health experts? Never drink any water onboard that isn’t in a sealed bottle, and they also recommend skipping onboard coffee and tea and using alcohol-based hand sanitizer with at least 60 percent alcohol instead of washing hands with airplane sink water. Unlike municipal water systems, aircraft drinking water tanks are refilled from multiple sources across a wide range of airports, often using ground equipment such as water cabinets, trucks, carts and hoses, and this fragmented supply chain can make consistent quality control difficult.
Anything with Ice Cubes
If the tap water is questionable, what do you think those ice cubes are made from? Exactly. Drinking potentially contaminated aircraft water can result in issues such as gastrointestinal illness and exposure to pathogens. The analysis found that 2.7 percent of samples tested positive for total coliform, a group of bacteria that’s found in the digestive tracts of humans and animals, as well as in plants and soil, and testing for coliform bacteria is important because their presence in drinking water indicates that disease-causing organisms could be in the water system.
I’ve personally seen flight attendants who’ve been in the industry for decades refuse drinks with ice. That should tell you everything. Even the carafes used to store the hot drinks on the plane may be cleaned with airplane tap water, which increases the risk of bacteria getting in there, and because of these factors flyers may wish to avoid consuming hot coffee or tea on commercial aircraft unless the beverage has been prepared using bottled water.
Unpasteurized Juice or Fresh-Squeezed Beverages
This might seem like a healthy choice compared to soda, but there’s a catch. Fresh juices or anything unpasteurized can be problematic at altitude where your immune system is already working overtime. The dry cabin air and pressure changes put stress on your body in ways most people don’t consider. While bottled, pasteurized juices are generally fine, anything that requires refrigeration and hasn’t been properly sealed raises concerns.
The confined space and recycled air of the cabin create a breeding ground for bacteria if food safety protocols aren’t followed perfectly. During my years in the skies, I watched countless passengers get sick from seemingly innocent choices. Stick with sealed, commercially produced beverages whenever possible. Your stomach will thank you later.
