This isn’t the first instance of getting drink names horribly wrong. (If you’re still ordering “Irish Car Bombs,” maybe read this.) But it turns out a drink with as innocuous-sounding a name as “Black and Tan” is historically offensive, and you should probably stop ordering it at Irish bars.

The drink got its name relatively innocently. A so-called “Black and Tan” is just a combination of Guinness and Bass Ale (though you can use other pale ales or lagers, Bass is traditional). The beers aren’t just thrown together, they’re layered, with the ale going in first, and quickly—creating a sturdy head on this beer will help you with the layering. You can use an inverted spoon to help you create the top layer of Guinness, which, despite its delicious stoutiness, is actually the lighter beer (technically speaking it’s got a lower specific gravity). (People actually make special tools to aid in layering, but the spoon seems like your best bet—it disperses the beer so it doesn’t all plunge at once.)

It would seem pretty un-offensive to call the drink a Black and Tan since it’s, well, black. And tan. But as with “Irish car bomb,” though maybe less obviously, the term Black and Tan has a totally different connotation in Irish history. (fairly recent Irish history, at that) “Black and Tan” was the nickname given to the British paramilitary force “formed to suppress the Irish independence movement in 1920 and 1921.” They were mostly of ex-servicemen who’d served in World War I and they all wore khakis and dark shirts.

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The army wasn’t simply a counter-force to the IRA; their methods were often pretty terrible, involving the burning of towns and even civilian slaughter. (In 1920, they infamously killed 12 civilians at a Dublin soccer match.) Clearly, the associations with “Black and Tan” aren’t something you’d be thinking about when you’re at the pub with your friends. Or eating ice cream, as Ben & Jerry’s found out in 2006 when they released a flavor called “Black and Tan,” only to get some serious backlash from the Irish. (They eventually withdrew the flavor and apologized.)

So what do you call a Black and Tan in an Irish pub? Another simple, and also visually accurate name: a Half and Half.