Generic use of eggs in beverages long predates their use in cocktails related drink forms. They were viewed as valued drink assets from their first drink application. Usually used for the consistency and foaminess egg imparts, it is often subdivided into its yolk white parts as separate cocktail constituents. In classic cocktail terminology, "golden" appended to the name of a cocktail often indicates the presence of egg yolk; "silver", the presence of egg white. When either "half a yolk" or "half an egg white" are specified, simply prepare two portions (2 drinks) instead of one.
other frothing agent and viscosity enhancer