(IO9) - Have you ever described a wine you were drinking as fruity, sweet, or having a hint of coconut? Well, congratulations, because you were totally drinking a component of koala urine.

In 1996 scientists were pleased to isolate a component of wine. They described it as “intense sweet and coconut-like smelling,” and called it “wine lactone.” The lactone part was right. Lactones are specific kinds of the odoriferous molecules known as esters, and the compound did have the right structure. It was the “wine” part that they got wrong. Yes, it was wrong even though the same lactone was isolated in Riesling wine, a sweet and fragrant type of wine, two years later. They were wrong even when wine lactone showed up in a lot of the foods that people associate with the scents in a good wine; foods like apples, citrus, and grapes.

They were wrong because wine lactone was discovered all the way back in 1975. I. A. Southwell discovered that if you feed a koala eucalyptus leaves and wait for it to pee, one of the things it will pee out is wine lactone. And yet we don’t call the stuff that’s in Riesling and other fruity wines “koala urine lactone.” The injustice of it!

Now, to be fair, the lactone in wine is only one specific isomer. Isomers of a molecule have the same chemical formula — the same amount of carbon, hydrogen, and so on — but have different chemical structures. While the isomer in wine has been identified, the koala urine isomer remains a beautiful mystery.