If you’re going to tipple in honor of St. Patrick today — and I know I will — be mindful of which brand of Irish booze you choose. Depending on how oldschool the pub is, a certain whiskey might be pointedly off the menu:

Distilled in County Antrim, in Ireland’s north, Bushmills has been derided by some as “that Protestant whiskey.” As Jameson comes from County Cork, in the heart of the Republic, it’s no surprise that some Catholics refuse to drink anything but.

“I know people that prefer one over the other, just for taste,” says George Clancy, a bartender at Patrick Kavanagh’s on Third Avenue. “But some would ask for Jameson, knowing what it stands for. Sometimes people will tell you why they’re drinking it, because they want to let you know they know what the difference is.”

It’s not as big a deal anymore, especially in terms of business: Until recently, both Jameson and Bushmills had the same corporate parent in Pernod-Ricard (Bushmills was sold to Diageo last summer).

But you never know. At the very least, you might find yourself bellying up to a bar, next to some old guy from Dublin, and get an earful as soon as you ask for a dram of “that Protestant whiskey”.

Or, I suppose, you could avoid the issue altogether and stick to the ubiquitous green beer. (Yuck.)

Personally, I’ve drank far more Jamesons than Bushmills. It’s not a preference, it’s just based on availability — seems like Jamesons is more common in bars. To be fair, I’ll doubledip tonight, where possible.