Here’s a useful bit of trivia: what are the only two countries in the world that have a local soft drink that outsells Coca-Cola? The answer: Scotland and Peru. The soft drinks in question, Scotland’s Irn Bru and Peru’s Inca Kola, share a remarkably similar profile, offering caffeine-rich fluorescent fizz that has spawned a national obsession.

Irn Bru has been made in Scotland since 1901 by the Barr family company. It started life back then as Iron Brew, which was an unquestionably more logical spelling, but in 1946 the government deemed the name to be false representation, due to the fact that the product isn’t actually brewed. Amazingly enough, however, it does contain iron: listed at the very end of the ingredient list is 0.002% ammonium ferric (III) citrate. Don’t know how much good that will do you, but apparently quite a lot, judging from the alarming number of toddlers to be seen on the streets here with bright orange bottles dangling from their mouths.

In fact, walk the streets of Edinburgh and you will see people of all ages and backgrounds quaffing the stuff. It’s touted as the world’s best hangover cure, which is a matter of serious debate among Scots. This claim does have some foundation in fact – all caffeinated drinks will soothe headaches to an extent, and sugary drinks replace lost fluids and sugars sustained after a particularly heavy night out (the only kind you can have here).

Irn Bru has been known for creating controversy with its advertisements, and in the words of one local "has the best adverts apart from beer".

Apparently its fame is spreading, as well – Russians, Japanese, and yes, even Americans are falling for it.

And what does it taste like, you ask? Irn Bru describes its taste as hints of citrus and vanilla. I don’t agree. Like all good phosphorescent soft drinks, its flavor profile builds with a full bouquet of cotton candy and finishes with a crescendo of pure bubblegum.