If you’ve ever seen one cococted in person, you can’t help but be impressed by the artistry underlying a pousse-café. The name, which translates to “layered drink,” is a reflection of the liqueurs selected, each sporting a different color, intensifying the magic.
The selections are virtually limitless. The layered effect is achieved by selecting and pouring liqueurs with different specific densities, which in turn depends on the amount of dissolved sugar and alcohol. Those with the most dissolved sugar and least alcohol are poured first, while beverages like rum, which is 75% alcohol by volume, come last.
To avoid becoming blended, the layers must be poured with extraordinary care. One reliable method is to use a spoon with the bowl inverted, to make the pour very gradual. The tip of the spoon should rest against the inside of the glass.
You are best off choosing a relatively narrow glass, since a broader glass will result in less-noticeable layers.