The structure here is classic: spirit (or zero-proof botanical), quinine, cold carbonation, and fresh citrus oils. Using a concentrated tonic syrup instead of pre-sweetened bottled tonic lets you control sweetness, dilution, and bitterness — exactly how a professional bar would. This is the cleanest way to drink a G&T if you're watching sugar or carbs.
Method
- Fill a highball or Spanish G&T goblet completely with fresh ice (large cubes work best).
- Add 1.5 oz London Dry Gin.
- Add 1.25 oz Top Hat Keto Sugar Free Tonic Water Syrup.
- Top with 4–6 oz Top Hat Premium Club Soda or fresh sparkling water from your soda maker.
- Give one gentle stir to integrate without losing carbonation.
- Garnish with sliced lime (or express a lime peel over the top) and serve immediately.
Pro move: Add the club soda last and stir once — this keeps bubbles tight and lifts the quinine aroma. If using a soda maker, carbonate the water first and pour it in; never add syrup to the soda maker bottle.
Swap gin for a zero-proof botanical spirit (Seedlip Garden, Monday Zero Gin, or similar) and keep the build identical. The quinine structure + carbonation still deliver a full "cocktail" experience — no alcohol required. Under 5 calories.
Spirited: ~97 calories, 0g sugar, 0g carbs from the tonic. All calories come from the gin (~97 cal per 1.5 oz). Zero-proof: Under 5 calories, 0g sugar, 0g carbs. This is one of the lowest-calorie cocktails you can make.
Want the full-sugar version? Try our Italian Gin & Tonic with East India Tonic Syrup — quinine-forward, botanical, and citrus-bright.
Own a SodaStream or soda maker? This recipe works perfectly with sparkling water from your machine. We wrote a full guide: 10 SodaStream Cocktail Recipes →
Comparing tonic brands? We wrote a full side-by-side breakdown of Fever-Tree, Schweppes, Q, and Top Hat: Best Tonic Water for Gin & Tonic →
All three tonic syrups in one box: Try our Tonic Syrup Trio — East India, Classic, and Sugar Free — and find your favorite.