Having only recently begun working my way through trying the myriad of delicious gins crafted from Scottish distilleries, I relied on friendly bartenders to cure my far-too-often indecisiveness when faced with rows of glinting bottles of fancy-looking gins, all with the eventual hope of being able to find that ‘perfect’ gin to put on the shelf back home.
I found ‘the one’ when my local bartender down at the Colinton Inn served up a surprise: fragrant and refreshing, it was a Hendrick’s Cucumber & Rose. I got ahold of a bottle and tried it myself one night and well…. it just wasn’t the same. Of course, I had made the rookie mistake of not using the same tonic - in fact, I couldn’t even remember which tonic the bartender used in the first place. This made me realise not that I had bad memory (I always knew that), but that my mind had never really paid attention to what tonic I drank with my gin. In fact, whilst I decided between raspberry, rhubarb or rose, the other more-than-half of the drink seemed always to be of less importance. So, I returned to find the precise tonic and, unsurprisingly enough, a load of ice and cucumber later I was able to create the perfect mix in the comfort - and cheapness - of my own home for myself and my friends.
This got me thinking, and I turned to my friend and asked “what exactly is tonic water?” She just shrugged. In fact, none of us knew what tonic water really was. I quenched my curiosity with a quick google search, and the results were rather strange…
The key ingredient in tonic water is a substance known as quinine, a bark extract which was first isolated in 1920 from a cinchona ‘fever tree’ , giving tonic water its uniquely bitter taste. Quinine, a medication used to treat malaria and babesiosis (another parasitic disease), was consumed in a mixture of sugar and carbonated water to make it more palatable, and in 1858 it was first marketed commercially. Soon after, gin was added by British officers stationed in colonial India, and thus a classic was born. From medicine to mixer, the tale of tonic was truly an interesting one.
Modern tonic waters are a far distant relative of the original; in fact, big brand tonic waters such as Schweppes contain barely any reactive compounds such as quinine in order to increase shelf time, and instead use flavouring agents like citric acid, sugar and preservatives.
The reasoning behind the perfect gin and tonic
Scientific evidence suggests that the burning sensation associated with drinking comes from ethanol reacting with the TRPV1 receptor, which lowers the temperature threshold for nerves to feel a burning sensation - these pain signals cause our sensory signals of taste and smell to weaken, so we stop figuring out what we're drinking or smelling. Furthermore, TRPV1 also reacts to acid, further lowering the amount of flavour signals processed by the brain. Hence, the composition of gins have been influenced by the acidity of tonics available.
Old school brands such as Gordons, Bombay and Tanqueray have been produced to adapt to the strength of old school tonics such as Schweppes, which was readily available in locations where these gins were produced. But due to the differences in tonic water composition, these old school gins tend to overpower the newer ‘premium' craft tonic waters.
The arrival of Fevertree and other craft tonic waters has inspired gin distillers to create more gins with more nuanced flavours. Tonics such as Fentimans contain quinine in their recipe, and also have a reasonable amount of citric acid and sugar; but it is their innovative 'botanical brewing’ process which they claim gives their tonic a uniquely floral taste. Revolutionary brand Fevertree have a huge selection of tonic waters, and also use natural quinine with varying amounts of citric acid and sugar between their different versions. In 2018, they were voted #1 Best Selling and #1 Top Trending Tonic Water Brand by Drink International in its Annual Brand Report.
On the other end of the spectrum are brands such as Q Tonic and East Imperial. East Imperial contains quinine, very low sugar and no citric acid, the closest to the original colonial tonic. Q Tonic adds a little more sugar and citric acid, which makes it perfect for new school craft gins.
By spending a little time reading about gin’s often forgotten partner, I began to understand why spending a small fortune on either gin or tonic alone wasn't improving my taste experience. G or T? It’s definitely both that make the difference.