float.

About float

A layered drink, sometimes called a pousse-café, is a kind of cocktail in which the slightly different densities of various liqueurs are used to create an array of colored layers, typically two to seven. The specific gravity of the liquid ingredients increases from top to bottom. Liqueurs with the most dissolved sugar and the least alcohol are densest and are put at the bottom. These include fruit juices and cream liqueurs. Those with the least water and the most alcohol, such as rum with 75% alcohol by volume, are floated on top.