The Best Tonic Waters and Mixers (2026): The Bigger Half of Your Gin and Tonic

Published 24 August 2026

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Pour a gin and tonic the way most people pour one — a 50ml measure, a 200ml bottle of tonic over it — and roughly four-fifths of what is in the glass is tonic water. Spend an extra ten pounds on the gin and you have improved a fifth of the drink. Change the tonic and you have changed the rest of it.

That is the entire argument for caring about mixers, and it is why this guide exists alongside our spirits guides rather than underneath them.

What tonic water actually is

Tonic is carbonated water, a sweetener, an acid, and quinine. The quinine is the part that makes it tonic rather than lemonade — it is what produces the dry, faintly medicinal bitterness that cuts through juniper.

Quinine comes from the bark of the cinchona tree, and in the UK it is a restricted flavouring: the Food Standards Agency’s register caps it at 100 mg/kg in non-alcoholic beverages, expressed as quinine base (FSA flavouring authorisation 14.011). That is a hard ceiling, and every tonic on the shelf sits at or below it. It is also why the ingredients line on these bottles reads “natural flavourings including quinine” rather than just “flavourings” — the quinine has to be named.

Two useful consequences:

• No tonic can be dramatically more bitter than another because of quinine alone. They are all working inside the same cap. What varies far more is the sugar, the acid and the citrus, which is what most “this one is sharper” impressions actually come from.
• Brands that say they use less quinine are telling you something real. The Artisan bottle below describes itself as low-quinine, and that is a legitimate design choice rather than a shortcut.

Why so many tonics now come in a “light” version

Because of tax. The Soft Drinks Industry Levy applies to drinks containing 5g or more of sugar per 100ml, at a lower rate from 5g to under 8g and a higher rate at 8g and above — currently £2.08 and £2.78 per 10 litres (HMRC guidance).

A full-sugar tonic sits comfortably in levy territory. A “light”, “skinny” or “refreshingly light” version is generally formulated to sit under it. So the split you see on the shelf is not only a health trend — it is a tax boundary that every mixer producer in the country has had to design around.

We have not printed sugar figures for individual bottles here. Recipes get reformulated, most obviously in response to this levy, and a number typed into an article stops being true without anything visibly changing. The nutrition panel on the bottle is the only version that is current.

Bottle size matters more than it sounds

Tonic is a carbonated product with nothing to protect it once opened. A 500ml bottle used across two drinks on two different evenings is noticeably flatter the second time, and flat tonic makes a gin and tonic taste sweet and dull in a way that no amount of good gin fixes.

This is why the trade standard is a 150ml or 200ml single-serve, and why almost every pack in this guide is one of those. Cans do the same job, chill faster and survive a picnic; glass is nicer on a table. Neither is meaningfully better in the glass.

How we picked these

This is a research-led roundup, not a tasting. We do not run a tasting panel and won’t pretend we have.

What we did instead: started from mixer brands with a real UK trading presence rather than a British-sounding name, checked each brand’s own account of what is in the bottle, kept only lines that are part of a standing multipack listing on Amazon UK rather than a seasonal or one-off release, and confirmed each listing resolves to the exact pack described.

No prices. Mixer multipacks are promotion-heavy and a figure typed here is wrong within a fortnight — use the live price on the listing.

We also looked at Luscombe, the Devon producer whose Devon Tonic Water is made with Dartmoor water, yuzu and quinine. It is a genuinely interesting bottle, but we could only find single 200ml bottles listed on Amazon UK rather than a case, so it is mentioned here rather than listed as a pick.

The tonics

Fever-Tree Premium Indian Tonic Water is the sensible default, and it earned that position. Charles Rolls and Tim Warrillow founded the company in London in 2004 on a straightforward observation: people were paying more for gin and then drowning it in whatever mixer the supermarket had. The name is the colloquial term for the cinchona tree. The tonic itself is restrained rather than characterful, which is precisely the job — if you are buying a distinctive gin, you want the tonic to carry it, not argue with it. Start here, and treat everything else as a reason to deviate.

Fever-Tree Refreshingly Light is the same recipe with the sugar pulled down under the levy threshold. Given that the tonic is four-fifths of the glass, this is the single change that most affects what a gin and tonic costs you nutritionally — far more than switching spirit. It is drier and shorter than the full-sugar version, which some people prefer on its own terms.

Franklin & Sons Premium Indian Tonic Water is the one with the strangest history. The original Franklin & Brothers was founded in 1886 by three brothers selling soft drinks from a shop on Rickmansworth High Street; the business traded for a century, stopped in 1989, and was relaunched by Global Brands in 2015. So “established 1886” is true, and there was also a twenty-six-year gap in the middle. That is worth knowing, and to the brand’s credit its own history page says so plainly rather than implying an unbroken line. In the glass it is a fuller, rounder, sweeter tonic than the Fever-Tree house style, bottled under a steel crown cap the company says keeps it fizzier for longer.

Fentimans Premium Indian Tonic Water is the most distinctive tonic in this guide by some distance. Fentimans was founded in 1905 by Thomas Fentiman, who acquired a ginger beer recipe as security against a loan that was never repaid, and it is still family-run — the business is now led by his great-grandson, Eldon Robson. Their drinks are botanically brewed: infused and fermented rather than simply blended from concentrate, with herbal infusions, Sicilian lemon oil and lemongrass alongside the quinine. The result is a tonic with an actual flavour of its own, which makes it excellent with a plain London Dry and a poor choice under a heavily flavoured gin, where the two will fight. The 150ml can is a one-drink size, so nothing goes flat in the fridge door.

Double Dutch Indian Tonic Water comes from a company founded in London by Dutch twin sisters Joyce and Raissa de Haas, who moved to the UK in 2014 and built the brand around food-and-drink pairing rather than a single house tonic. Most of the attention goes to their unusual flavours; the Indian tonic is the classical one, and the sensible entry point if you want to see whether the pairing idea holds up before buying a case of cucumber and watermelon.

Artisan Classic London Tonic Water is the softest option here, and the brand says so itself — it is deliberately low on quinine, aimed at people who find tonic too bitter. Worth naming one thing honestly: the name says London, but the brand’s own founding story starts in a bar in Sydney, where British drinks entrepreneur Steve Cooper, designer Alan Walsh and Australian bartender Mikey Enright came up with it (BeverageDaily, 2019). That is not a mark against the drink, which is well made and sold throughout the UK — it is just a reminder that a place name on a mixer label is branding, not provenance. The same rule we apply to British rum applies to tonic.

Beyond tonic: ginger for the brown spirits

Gin gets all the mixer attention, but the two bottles below cover most of what whisky and rum need.

Fever-Tree Premium Ginger Ale is built in the dry style — it is sold as a dry ginger ale in several markets — and Fever-Tree positions it explicitly as a mixer for whiskies, bourbons and rums rather than as a soft drink. A measure of English single malt or an aged British rum lengthened with this stays recognisably itself; the same measure in a sugary ginger ale becomes a soft drink with a whisky note. It is the natural companion to our guides to English and Welsh whisky and British rum.

Fentimans Ginger Beer is a different drink entirely — brewed from fermented ginger root rather than flavoured afterwards, and hot enough to hold its shape against a dark rum. This is the bottle for a Dark ‘n’ Stormy or a Moscow Mule, and the only one in this guide we would suggest buying to drink on its own.

What to buy first

You own one gin and want one tonic: Fever-Tree Premium Indian. It flatters almost everything and offends nothing.

You drink G&Ts several times a week: Fever-Tree Refreshingly Light. The tonic is where the sugar in that drink lives, and this is a smaller change than drinking less.

You want to actually taste the difference a mixer makes: buy Fentimans Premium Indian alongside whichever tonic you use now and make the same G&T twice. Botanically brewed against blended is the widest gap in this guide, and the cheapest way to find out if you care.

You find tonic too bitter: Artisan Classic London.

You mostly drink whisky or rum: skip the tonic entirely — Fever-Tree Premium Ginger Ale for sipping long, Fentimans Ginger Beer for cocktails.

If you are building the spirits side of the shelf to match, our guides to the best British gins, British rum and English and Welsh whisky are the places to start.

The honest summary: the mixer is most of the drink, so it deserves more thought than it usually gets — but the differences between good tonics are smaller than the marketing suggests, because the law caps the ingredient that defines the category. Buy single-serve sizes, read the sugar panel rather than the front label, and spend the saved effort on the spirit.