The Gin and Tonic is a highball that seems to meet the classic definition of a cocktail, in a loosely defined way. A cocktail in the 1800s was the combination of a spirit, sugar and bitters plus a diluent for the weak part. In a Gin and Tonic, you have gin, which is, of course, the spirit part of the equation, the soda in the tonic water is weak and the quinine is the bitter flavour. Most commercial tonic water has some sugar in it, roughly 2 teaspoons (8 grams) per 3 oz (100 ml), which is sweet enough. Strong, weak, sweet, and bitter, it looks like a cocktail to me.
Some of the new boutique tonic waters have less sugar and more quinine which gives a more potent version of the G&T. This may appeal to some people, but it can be a bit challenging to the taste buds of the average drinker.
Some creative bartenders are experimenting with cinchona bark which is the original source of quinine hundreds of years ago. In its unprocessed state cinchona is not a direct substitute for tonic water, and can be overly bitter with a strong wood flavour and in some cases, it tastes like dirt. Though closer to the original medicinal purposes—quinine was used as prophylactic and treatment for malaria—the gin was used to hide the flavour and make the medicine go down better. It’s probably not necessary today, except for historical tasting purposes.
The traditional Gin and Tonic should be a pleasantly bitter cocktail. The combination of the gin with the tonic almost seems to be a match made before the universe began. The two flavours come together in a way that neither is dominant, assuming the drink is made right. But the basic flavours still need something to bind them together and that binding agent is lime. Without the lime, the Gin and Tonic can taste flat and not as refreshing on a hot summer day. You must use fresh limes, no crunchy old limes and don’t use bar sour mix. A generous squeeze or wedge of lime (think 1/6th to 1/4 of a lime) will improve the quality significantly.
Finally, good ice is the finishing touch. Pack the glass full and use large chunks, not crushed ice. The colder this drink is the more refreshing it will be.
As always, good ingredients will help this drink, and any other drink, reach its full potential.If you like Gin and Tonic, you might want to try the Moscow Mule for a spicier take on a highball.