Cocktails were once simple mixtures of aqueous solutions and spirits. Progressively, other ingredients, such as cream, sugar, or herbs, were added, but with the advent of molecular cooking, new tools have been used, and various additions such as alginate pearls have been proposed. This chapter describes a cocktail with ten layers, that is, many more than the three of the famous Irish coffee. Cocktails are defined as alcoholic drinks consisting of a spirit or spirits mixed with other ingredients, such as fruit juice or cream. Mixed drinks without alcohol that resemble cocktails are known as “mocktails” or “virgin cocktails”. The Welcome coffee was designed as an educational tool in 1997, but it was created only in October 2005 by the bartender of the Paris Ritz hotel, because a seminar for bartenders had been organized in this hotel. In it, very simple ideas were used, and in particular the ranking of layers by order of densities: water, oil, ethanol, and air.