THERE exists a genre of information which might be termed “little-known facts that everyone knows”. It is the sort of tidbit you expect to amaze your friends at a dinner party, but which is greeted with rolled eyes. Casinos don’t have clocks or windows. Alanis Morissette’s song “Ironic” contains no example of irony. The body exerts more calories digesting celery than is contained within the vegetable. (Except the last of these facts—and everyone knows this—is in fact untrue.)

Then there is Bloody Marys and aeroplanes. Have you ever wondered why the only time most people fancy gulping down vodka, tomato juice and Worcestershire sauce is when strapped into the seat of a passenger jet? It is a little-known fact (that everyone knows) that our taste buds are dampened by the low pressure and humidity in the cabin, as well as the white noise of the engines. This particularly affects flavours that are sweet and salty. The umami taste, however, remains prominent. Tomato juice is high in umami. Worcestershire sauce, meanwhile, is what one cook calls an “umami powerhouse”. Hence a Bloody Mary suddenly becomes more appealing at 30,000 feet. (Heathens who substitute tabasco for Worcestershire sauce are only fooling themselves.)

This has led airlines to think more seriously about which drinks to serve. Most already know to stock up on tomato juice; Lufthansa gets through about 1.8m litres of the stuff each year. Much of that is wasted on economy-class passengers. But for carriers looking to lure posh types at the front of the plane, selecting drinks for altitude has become a source of competitive advantage.

On February 22nd Cathay Pacific unveiled its own craft beer for first- and business-class flyers on planes between London and Hong Kong. It seems a thoughtful effort. The hops have been toned down to make it taste less bitter, and fruit and honey have been added as sweeteners. That probably makes it a sickly beer at ground level (alas, Gulliver has yet to try it), but more palatable in a pressurised cabin than the standard fare.

Wine gets the treatment from airlines too. According to Will Lyons, a drinks journalist, writing in a Wall Street Journal collection, “Wines taste very different in the air. A combination of altitude and low humidity tends to accentuate a wine’s acidity and alcohol.” Not only that, he goes on: “The cabin’s dry atmosphere will make the tannins—the bitter-tasting compounds found in red wine—more pronounced.” Hence older wines tend to taste better than young ones because they are softer, and red-berry flavours are preferable to citrus ones. “My advice to flyers has always been to opt for those wines that are bigger, riper and more expressive, with low acidity. Something like a Merlot, Pinotage or Shiraz for reds or Chardonnay, Semillon and Viognier for whites,” he writes.

For those squeezed into the back half, a different approach is required. Guides abound about how to make your own cocktails on planes, using the materials to hand on the flight attendant’s trolley. Some also require homework. To make an Old-fashioned, for example, one site suggests packing Angostura bitters in a pipette in your carry-on luggage, as well as slices of orange, sugar lumps and a muddler. Once on board you need to order a miniature of bourbon and two plastic glasses, one filled with ice.

Frankly, that all sounds a bit of a palaver. For those desperate to pretend they are living the high life, even when their knees are wedged against their chin in an economy seat, better just to order champagne. Except, sadly, the ultimate jetsetter’s tipple is also one of the worst flyers. Bubbly does not fare well at altitude; it is too acidic to taste nice. Ms Morrissette would no doubt describe that as ironic.