Purple Skittles may be grape-flavored in the US, but the candy tastes entirely different internationally.

In countries including the UK and parts of Europe, the purple Skittles' flavor is black currant, Atlas Obscura's Ella Morton reported. And, it's not just a random quirk — there's a real, historical reason for the difference.

In the early 20th century, the US government made it illegal to grow black currants anywhere in the country because the berry was spreading white pine blister rust, a wood-destroying disease.

Now, even though the federal ban has been lifted and it's legal to grow black currants in most states, Americans simply haven't developed a taste for the berry, which is hugely popular in the UK and other European nations.

So, what does the black currant Skittle taste like?

For one, it's more tart than the American "grape" Skittle. Atlas Obscura described the black currant as a mix between blueberry and cranberry, and the candy has a similar, berry-tinged flavor that Americans may find hard to place.

"I can't think of what this reminds me of, and it's driving me crazy!" reads a review of black currant Skittles on the Tumblr mmmdeliciousness. "Some sort of old fashioned candy or something... It make eating the grape ones a bit nauseating."

There are other slight differences between the American and British Skittles. Candy-centric blogs have described the European Skittles as softer with thinner shells, and stronger citrus undertones in the yellow and green flavors.