Juice softens, enlivens and freshens a cocktail, and gives a variety of flavor that no spirit on its own can match. Fresh juice in season is always the place to start. Second best is packaged juice that’s as close to the real thing as possible: look for 100% juice on the label and an absence of high fructose corn syrup in the ingredients.
A crucial component of any good cocktail program is fresh lemon and lime juice, squeezed directly from the fruit. Store lemons and limes in your fridge to keep them fresh. Never pasteurize or freeze citrus juice or keep it for more than 48 hours. And avoid store-bought lemon or lime juice in those plastic fruit-shaped containers lest you mortally wound your cocktail, or irrevocably offend your local bartender.