Every cocktail, properly so called, must contain two different types of ingredients. It also may, but need not necessarily, contain a third type. They are:Winner to receive a $500 shopping spree at KegWorks. (They've put together a "help page" as well.) Entry deadline is January 31. Get cracking! When you're ready, submit your entry here.
1. A base;
2. A modifying, smoothing, or aromatizing agent;
3. Additional special flavoring and coloring ingredients.
Let us consider them in order.
1. The Base This is the fundamental and distinguishing ingredient of the cocktail and must always comprise more than 50 per cent of the entire volume. Indeed, with a few rare exceptions it should constitute from 75 per cent of total volume upward. Strictly speaking, the base must always consist of spirituous liquors – whisky, gin, rum, brandy, etc. [...] Within certain limits, however, it is possible to combine two (perhaps even more, but this is dangerous) liquors as a base. [...] ...the indiscriminate mixture of three or four or five different liquors is practically certain to destroy the distinguishing flavor and aroma of all and produce a result about as palatable as a blend of castor oil and gasoline.
2. The Modifying Agent It is difficult to find a word that exactly describes this ingredient (or group of ingredients) and, for want of a better term, I have called it the modifying agent or modifier. It is this ingredient, in combination with the base of spirituous liquor, which characterizes the cocktail. Without this ingredient the base, no matter how violently shaken and how thoroughly chilled, would still not be a cocktail but would remain merely chilled liquor. Its function is to smooth down the biting sharpness of the raw liquor and, at the same time, to point up and add character to its natural flavor.
3. Special Flavoring and Coloring Agents These include all the various cordials or liqueurs, which will be discussed later, as well as non-alcoholic fruit syrups. [...] Of all the factors involved in the mixing of cocktails, flavoring agents are undoubtedly the most abused. [...] These special flavoring agents should be measured by drops or dashes, not by ponies or jiggers. [...] Whenever you see a recipe calling for equal parts of rum, brandy, Cointreau, curaçao, and Benedictine, with a dash of absinthe, shun it as you would the very devil.