Tonic Water
Tonic water is carbonated water flavoured with quinine and sweetened, with no alcohol in it. In Great Britain the Food Standards Agency’s flavourings register caps quinine at 100mg per kilo of drink, and Regulation (EU) 1169/2011 requires it to be named in the ingredients, which is why every label reads "flavourings including quinine". It is the bitter half of a gin and tonic, and the style on the label decides how much sugar comes with it.
Quick Facts
We keep an opened bottle in the fridge and use it within a day or two; flat tonic tastes dull and oversweet.
None of the 14 listed allergens. Recipes change: check the bottle.
About Tonic Water
Flavour Profile
Primary Flavours
Tasting Notes
Bitter-sweet with a clean quinine backbone and a gentle citrus lift; balances botanical spirits without overpowering them.
Quinine is what makes it tonic
Strip out the quinine and tonic water is a lightly sweetened, slightly acidic soda. The quinine, an alkaloid from the bark of the cinchona tree, supplies the clean bitterness that makes a gin and tonic taste dry even though there is sugar in it. Quinine is also a medicine, so the law treats it carefully. In Great Britain a soft drink may carry no more than 100mg of it per kilo, counted as quinine base, under the flavourings register the Food Standards Agency maintains, and the label has to name quinine straight after the word flavourings.
That is why tonic is a flavouring dose and not a treatment. The Oxford Companion’s history runs from cinchona used against the chills of malaria, through quinine isolated in 1820, to soda water with quinine and sweetening, to gin added on top; the first commercial Indian tonic water was patented by the Schweppes partners in 1858.
The style on the label sets the sugar and the flavour
Indian tonic is the reference: quinine, citrus oils and full sugar, 7.4g per 100ml in Fever-Tree’s Premium Indian. A light tonic roughly halves that, usually with fructose, which leaves the quinine more prominent. Flavoured tonics keep the same bitter base and add one idea on top, and the name tells you which.
Tonic styles and what each one does (the sugar figure from Fever-Tree’s UK site)
Indian
- What it adds
- Quinine bitterness with full sugar, 7.4g per 100ml in Fever-Tree’s Premium Indian: the reference style
- Suits
- Juniper-led London dry; navy strength at the long end of the ratio
Light
- What it adds
- About half the sugar, usually fructose, which leaves the quinine sharper
- Suits
- Citrus-led gins, and Old Tom, which carries its own sugar
Lemon
- What it adds
- Lemon through the whole drink, and more acid
- Suits
- Sloe gin and other sweet fruit liqueurs
Mediterranean
- What it adds
- Herbs such as rosemary and thyme, or in some bottles citrus instead
- Suits
- Floral and contemporary gins, and vodka
Floral or fruit
- What it adds
- Elderflower, cucumber or rhubarb, with the quinine keeping it dry
- Suits
- A plain gin that is not already fruity
Aromatic
- What it adds
- Angostura bark and warm spice, often coloured pink
- Suits
- A juniper-led gin, as in the Pink Gin & Tonic
Savoury
- What it adds
- Herbs and a briny edge, with the sugar pulled back
- Suits
- A herbal gin or a dry vermouth
| Style | What it adds | Suits |
|---|---|---|
| Indian | Quinine bitterness with full sugar, 7.4g per 100ml in Fever-Tree’s Premium Indian: the reference style | Juniper-led London dry; navy strength at the long end of the ratio |
| Light | About half the sugar, usually fructose, which leaves the quinine sharper | Citrus-led gins, and Old Tom, which carries its own sugar |
| Lemon | Lemon through the whole drink, and more acid | Sloe gin and other sweet fruit liqueurs |
| Mediterranean | Herbs such as rosemary and thyme, or in some bottles citrus instead | Floral and contemporary gins, and vodka |
| Floral or fruit | Elderflower, cucumber or rhubarb, with the quinine keeping it dry | A plain gin that is not already fruity |
| Aromatic | Angostura bark and warm spice, often coloured pink | A juniper-led gin, as in the Pink Gin & Tonic |
| Savoury | Herbs and a briny edge, with the sugar pulled back | A herbal gin or a dry vermouth |
Match the tonic to the spirit, then measure it
Start with the gin’s lead flavour, then choose the tonic that lets it through. A juniper-led London dry wants an Indian tonic: its full sugar and quinine stand up to the juniper. A citrus-led gin suits a light or a lemon tonic, which carry the citrus rather than covering it. Floral and contemporary gins take a Mediterranean tonic, whose herbs sit under the flowers rather than competing with them. Old Tom carries its own sugar, so pair it with a light tonic. Navy strength takes an Indian tonic at the long end of the ratio, 50ml to 150ml, with more alcohol to dilute. Sloe gin is a sweet liqueur rather than a gin, and a lemon tonic sharpens it: that is the Sloe Gin & Lemon Tonic.
The house pour is one part gin to two of tonic, 50ml to 100ml, which is the ratio of our Gin and Tonic; one to three, 50ml to 150ml, gives a lighter drink, the ratio of the Pink Gin & Tonic, and past that the gin disappears. A copa glass gathers the aroma over a wide surface; a highball glass keeps the drink colder and the fizz in longer. Either way, fill the glass with ice first, to the top: a full glass melts more slowly than a few cubes. Gin, then tonic down the inside of the glass, then one stir.
The garnish follows the tonic, not the gin. Lime or lemon with an Indian tonic, lemon peel with a lemon tonic, rosemary or grapefruit with a Mediterranean tonic, cucumber with a cucumber tonic. The Vodka & Mediterranean Tonic shows the rule with no gin in it: the tonic sets the garnish.
The fizz is the part that goes first
Open the bottle at the last moment and pour it down the inside of a glass already packed with cubed ice. Carbon dioxide stays dissolved far better in cold liquid, so chilled tonic keeps its bubbles through the pour, and a single lift of the bar spoon mixes it. We give an opened bottle a day or two in the fridge with the cap screwed down; after that it tastes sweet and dull, and soda water is a better standby than flat tonic.
Using Tonic Water
Usage
Poured cold from a freshly opened bottle over a glass full of ice, after the spirit and down the side of the glass. Our Gin and Tonic takes 100ml to 50ml of gin; longer serves run to 150ml. Stir once, from the bottom.
Pro Tip
If a good gin vanishes under the tonic, change the tonic before the gin. A lighter style with less sugar leaves room for the botanicals; pouring more gin only makes a stronger drink that still tastes of tonic.
Top Tips
- Buy small bottles. A 200ml bottle fills one long drink; a litre opened for two drinks is flat by the third.
- Taste a new tonic on its own before mixing. Sugar and bitterness vary more between labels than between most gins.
- Keep it in the fridge before opening. Cold liquid holds its gas through the pour; warm tonic foams up and loses it.
- Read the style, not the colour of the label: light means less sugar, Mediterranean means herbs, aromatic means bark and spice.
Possible Substitutions
- Soda Water: with a dash of aromatic bitters: drier, no quinine
- Fever-Tree Refreshingly Light Lemon Tonic Water: lemon tonic: more acid, citrus through the drink
Production Method
Carbonated water sweetened with sugar or, in light styles, fructose, sharpened with citric acid and flavoured with quinine and other natural flavourings. Quinine for drinks is used as a salt such as quinine hydrochloride or sulphate, within the 100mg per kilo the Food Standards Agency’s flavourings register allows in a soft drink.
History & Context
The Oxford Companion, a secondary source, says cinchona was long used against the chills of malaria, that quinine was isolated in 1820, and that the Schweppes partners patented commercial “Indian tonic water”, soda water with quinine and sweetening, in 1858; paired with gin, it was adopted as a daily quencher by British subjects in tropical areas.
More to explore
Common Questions
What is tonic water?
Why is tonic water bitter?
How much quinine is in tonic water?
Light or full-sugar tonic: which should I use?
Can I use soda water instead of tonic?
How long does tonic water keep once opened?
Is bitter lemon the same as tonic water?
Which tonic goes with which gin?
What is the gin to tonic ratio?
Sources.
Checked between 17 October and 19 October 2026.
- Food Standards Agency, “Flavouring authorisations: quinine”.
- legislation.gov.uk, “Regulation (EU) No 1169/2011, Annex VII (as retained in UK law)”.
- The Oxford Companion to Spirits and Cocktails, “tonic water” (secondary source: cinchona against the chills of malaria; quinine isolated in 1820; Schweppes’s development from 1851; “Indian tonic water” patented in 1858; adopted with gin by British subjects in tropical areas; commercial distribution in the 1870s).
- Fever-Tree (UK), “Premium Indian Tonic Water”.
- Fever-Tree (UK), “Mediterranean Tonic Water”.
From the Guides
Made with Tonic Water
Featured In These Cocktails
Often Used With
Guide by Jerry Can Spirits · Updated 19 October 2026