Choose plain soda water if you want a mixer without sugar or tonic sweetness: Fentimans and Schweppes list 0g sugars per 100ml for their soda waters, and Fentimans says its version has no artificial sweeteners. If you want quinine-led tonic flavour, a no-sugar slimline tonic is another option, but check for sweeteners: Schweppes Slimline contains aspartame and carries a phenylalanine warning. Do not use “light” as a substitute for checking a no-added-sugar claim; the cited Fever-Tree and Fentimans light tonics list fructose or sugar.
Start with a plain soda water if guests want a mixer without tonic sweetness. Fentimans lists 0g sugar per 100ml and says its Soda Water has no artificial sweeteners; check the exact pack against any other ingredient preferences.
A slimline tonic retains quinine-led tonic character. Schweppes Slimline is labelled no sugar, but Sainsbury’s lists aspartame among its ingredients and a warning that it contains a source of phenylalanine.
Match bottle or multipack sizes to the drinks you plan to serve, and check availability before relying on one mixer. Compare current labels if you need a substitute: products labelled no added sugar and no sugar need not have the same ingredients.
Decide whether the drinks call for tonic’s quinine flavour or a plainer soda base, then compare claims, ingredients and pack sizes on the exact products you intend to buy.
| Priority | What to check | Your needs |
|---|---|---|
| Sugar wording | Check the front-of-pack claim, ingredients and sugars per 100ml. The Advertising Standards Authority’s September 2025 guidance on the Great Britain claim says “no added sugars” excludes added mono- or disaccharides and other foods used for sweetening; “light” is not the same claim. | I want the mixer to meet a no-added-sugar requirement, rather than relying on “light” wording. Fever-Tree Refreshingly Light lists fructose, while Fentimans Naturally Light lists sugar. |
| Sweeteners | Read the ingredients as well as the sugar declaration. Sainsbury’s lists aspartame and a “Contains a Source of Phenylalanine” warning for Schweppes Slimline Tonic. | A no-sugar tonic works for my drinks only if its sweeteners are acceptable to the people drinking it. |
| Drink style | Check whether you need quinine-containing tonic or soda water without tonic flavour. Compare any other flavouring ingredients on the particular pack. | For a G&T-style drink, I want tonic character; for a plainer base that guests can flavour themselves, I would choose soda water. |
| Pack and stock | Check the volume, number of servings and current availability. Recheck the physical label when substituting a different product or pack. | I’m buying for several guests, so the format needs to fit the planned drinks without relying on one particular product being in stock. |
Fever-Tree Refreshingly Light Indian Tonic Water lists fructose. Fentimans Naturally Light Tonic Water lists sugar and 3.4g sugar per 100ml, according to the manufacturers.
For a no-added-sugar shop, read the ingredient list and the exact claim rather than choosing by “light” wording alone.
Sainsbury’s lists Schweppes Slimline Tonic as no sugar, but its ingredients include aspartame and its label carries a phenylalanine warning.
If a guest wants to avoid sweeteners, check the tonic ingredients or consider a plain soda water with an acceptable ingredient list.
A particular no-added-sugar tonic may not be available when you shop. A replacement can also have different sweeteners or other ingredients.
Check stock before finalising the drinks list, and compare the replacement’s label rather than assuming the products are interchangeable.
Tonic contributes quinine flavour; the Fentimans and Schweppes soda waters described by their manufacturers do not list quinine in their ingredients.
Choose the mixer for the drinks you plan to make. If serving both tonic drinks and plainer mixed drinks, consider stocking each type.
Its Soda Water and Naturally Light Tonic Water illustrate why the product name matters more than the brand alone.
Schweppes has a plain soda water and a slimline tonic, suited to different flavour and ingredient preferences.
Its Refreshingly Light Indian Tonic Water is a flavoured tonic option, not an automatic match for a no-added-sugar list.
Britvic announced classic and zero-sugar Indian Tonic Water in 330ml six-packs for grocery retail in September 2023.
This Schweppes slimline tonic is an option when you want tonic flavour and a no-sugar label for Christmas drinks, rather than a plain soda-water base.
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For tonic-based drinks at a gathering, this pack contains twelve 150ml servings and is labelled no sugar. Sainsbury’s listing for the same pack names quinine and aspartame and carries a “Contains a Source of Phenylalanine” warning. Check the current label if guests are avoiding sweeteners or these ingredients.
No. The Advertising Standards Authority’s September 2025 guidance describes conditions for a “no added sugars” claim in Great Britain, including no added mono- or disaccharides or other foods used for sweetening. A no-sugar drink can still contain sweeteners: Sainsbury’s lists aspartame in Schweppes Slimline Tonic.
Start by checking a plain soda water’s exact label. Fentimans lists 0g sugar per 100ml for its Soda Water and says it contains no artificial sweeteners; Coca-Cola Great Britain lists 0g sugars per 100ml and carbonated water plus sodium bicarbonate for Schweppes Soda Water.
Not on that wording alone. Fever-Tree lists fructose in its Refreshingly Light Indian Tonic Water, while Fentimans lists sugar and 3.4g sugar per 100ml in its Naturally Light Tonic Water. Check the claim and ingredients on the particular tonic.
Compare a substitute’s physical label before buying it. Check its sugar declaration, sweeteners, quinine and pack size against the drinks and guests you are shopping for; Tesco advises reading product labels because formulations can change.