Measurement, Units, Equipment
Drinks should be measured by volume. I am a big believer in cooking by weight, but I mix drinks by volume,
The volume determines how close the top of the finished drink will be to the rim of the glass. This liquid line is called the wash line, and maintaining a proper wash line is essential to good bartending. In a professional setting, it is essential that your drinks be consistent. Having standard wash lines for each drink you prepare gives you an instant visual check that everything is okay. If your wash line is wrong, something is wrong with the drink.
American cocktail recipes are always written in ounces. Before my metric friends get in a tizzy, let me say that in a cocktail recipe the word ounces is really just another way to say “parts.” Cocktail recipes are all about ratios, and ratio measurements are in parts: 2 parts booze plus ½ part syrup and ¾ part juice and the like. In this book, 1 part equals 1 ounce equals 30 milliliters.