Irish Coffee Day

What the day is

Irish Coffee Day is observed on January 25. The drink is coffee, Irish whiskey, sugar and a layer of cream that floats rather than mixing.

Origin and background

It was created in the 1940s at the flying boat terminal at Foynes in County Limerick, by a chef named Joe Sheridan, for passengers arriving cold and miserable off long transatlantic crossings. The story that a passenger asked whether it was Brazilian coffee and was told it was Irish is part of the standard account.

It reached America through a journalist who drank it at Shannon and brought the idea to the Buena Vista in San Francisco in 1952. The bar then spent a considerable time failing to reproduce it, because the cream kept sinking, and the problem is a real one. Cream floats only if it is less dense than the liquid beneath, and hot sweetened coffee is denser than plain coffee, which is why the sugar is not optional. The cream must also be lightly whipped, thickened enough to hold together but still pourable, since fully whipped cream sits as a lump and unwhipped cream simply dissolves. The bar reportedly worked with a local dairy before they got it consistent, and the recipe became the thing the place is known for.

The pouring technique follows from the physics. Cream poured over the back of a warmed spoon spreads sideways and settles gently rather than punching down through the surface.

The drink is served without a straw and drunk through the cream, which is the point of the layering, since each mouthful is hot coffee arriving through cold cream.

How to take part

• Do not skip the sugar. It is structural rather than sweetening.
• Whip the cream only until it thickens and still pours.
• Warm the glass first, which keeps the coffee hot enough to hold the layer.
• Pour over the back of a spoon held against the surface.
• Drink it through the cream, and do not stir. Drink responsibly.