Why We Make Our Own Tonic: Five Citrus and a Numbing Pepper

Tonic is the ingredient nobody thinks about. You order a gin and tonic, you get judged on the gin, and the other two thirds of the glass arrives out of a gun or a small bottle and is treated as a solved problem.

It is not a solved problem. It is usually the reason the drink is boring.

What Tonic Was Supposed to Be

Tonic water exists because of quinine, which comes from the bark of the cinchona tree and was the first effective treatment for malaria. British officers in India took it dissolved in water, found it unbearably bitter, and started adding sugar, citrus and gin. That is the entire origin of the drink.

Quinine is intensely bitter and that bitterness was the point. It is also what makes tonic glow under a blacklight, which is a genuinely useful way to check whether there is any real quinine in what you are drinking.

Modern commercial tonic has drifted a long way from that. Most of it is sugar, water, citric acid, and enough quinine to justify the name. It is sweet rather than bitter, and it flattens whatever gin you put in it.

So We Build It

Our tonic uses five Japanese citrus varieties from Kankitsu Labo, and the reason there are five is that no single citrus does everything.

Yuzu is the aromatic. Almost all of its value is in the peel, which is floral and complicated in a way no other citrus manages. There is very little juice in one and it is not the point.

Amanatsu is sweet-tart with real volume of juice, so it carries body and keeps the blend from being all top notes.

Iyokan is rounder and more fragrant than yuzu, and it fills the middle.

Kawachi Bankan is the interesting one. It is mildly sweet with a clean bitterness that is refreshing rather than harsh, and in a tonic that bitterness is doing the job quinine used to do.

Setouchi Lemon brings straightforward balanced acid and a gentle aroma, from the region that grows most of Japan's lemons.

Stacked together you get brightness, body, aroma and bitterness from four different directions instead of one flavouring.

The Sansho

Then sansho, and this is the part people notice.

Sansho is not chilli heat and it is not black pepper heat. It contains sanshool compounds, the same family responsible for the buzz in Sichuan pepper, and they act directly on the nerve endings in your lips and tongue. The sensation is a light tingling or numbness rather than burning.

In a long carbonated drink that is a genuinely strange and good effect, because carbonation is already a mild irritant and the two things reinforce each other. It makes the drink feel more alive than it should.

Sansho also smells citrusy on its own, which is why it belongs here rather than being a novelty.

Where to Drink It

It goes into Megumi's Gin & Tonic, with the house tonic, the five citruses, sansho and spices, paired with Japanese gin.

Kankitsu Labo, who supply the citrus, work on getting Japanese citrus varieties into the American market and supporting the growers behind them. Most of these fruits are effectively impossible to buy here otherwise, which is why the tonic tastes like something you have not had before. They are on Instagram at @kankitsulabo.