Watermelon Cooler
A Watermelon Cooler is 150ml of fresh watermelon juice, blended and strained, with 25ml of fresh lime juice over ice in a highball glass, topped with soda water and stirred once. It is alcohol-free. A splash of simple syrup goes in only if the melon is under-ripe. USDA FoodData Central puts raw watermelon at about 91% water and 6% total sugars, with enough sugar of its own that the drink rarely needs more. What it lacks is acid, which is the lime’s job, and sparkle, which is the soda’s. Juice from a carton is usually pasteurised and tastes cooked beside fresh; blending your own takes a minute. We keep the juice and lime in the fridge for a day, so a jug can be ready before anyone arrives. The soda goes in at the last moment, glass by glass.
Glassware: Highball Glass
Garnish: Small watermelon wedge on the rim and Mint sprig slapped once and planted beside the wedge
Ingredients
150ml
Blended from ripe flesh and passed through a fine sieve. Press the pulp lightly; forcing it through clouds the juice. One melon gives far more than a glass, and the spare freezes well.
25ml
Squeezed the same day. Watermelon has almost no acidity, so the lime gives the drink its shape. Without it the glass tastes of sweet water.
A splash (optional)
Only if the melon needs it. One to one by weight, added a teaspoon at a time and tasted after each.
Top
Cold, from a bottle opened that day, and poured last. It lengthens the drink and lifts the melon’s smell. Tonic would add bitterness and sugar the drink does not need.
Instructions
Blend chunks of ripe watermelon until smooth, then strain through a fine sieve.
Fill a highball glass with ice and add 150ml of the watermelon juice and the lime juice.
Taste, and add a splash of simple syrup only if the melon needs it.
Top with soda water, poured gently down the inside of the glass, and stir once.
Garnish with a small watermelon wedge on the rim and a sprig of mint, slapped once.
Our version
Our own alcohol-free cooler: fresh watermelon juice, lime and soda, with syrup only when the fruit needs it.
Source: our own specification. Last checked 10 October 2026.
Expert Tip
Taste the strained juice before you build. If it is sweet on its own, it will be balanced once the lime and soda go in. The syrup is for a melon picked too early, not a fixed part of the drink. Choose the melon by its weight and its field spot. A ripe one feels heavy for its size and has a creamy yellow patch where it lay on the ground. A white patch, or none, means it was picked early. Pour the soda gently down the inside of the glass and stir once. Everything else can be made ahead; the bubbles cannot.
Behind the Watermelon Cooler
Flavour Profile
The Fruit Is the Drink
Watermelon is mostly water, with some sugar and almost no acid, so its juice is nearly a drink before anything is added. The Cooler edits it. Lime gives it a sharp edge, soda lengthens it and lifts the smell, and ice keeps it cold.
That is why the recipe carries no syrup by default. Judge the sweetness by tasting the juice, not by a measure.
Making the Juice
No juicer is needed. Cut the flesh from the rind, pick out the obvious seeds and blend until smooth. Pass it through a fine sieve over a bowl, pressing lightly with the back of a spoon. Fresh juice is bright pink and tastes of cut melon; by the next day it has dulled, so make it the day you serve it.
Choosing the Melon
The drink is decided when you buy the fruit. A ripe watermelon is heavy for its size, has a creamy yellow field spot and sounds hollow when tapped. Pre-cut wedges are a fair fallback if the flesh is deep pink and the cut face looks moist rather than glassy.
Three Lime and Soda Drinks
The Watermelon Cooler beside the Watermelon Martini and the Virgin Mojito
Watermelon Cooler (ours)
- Fruit or herb
- 150ml watermelon juice, strained
- Citrus
- 25ml lime
- Sweetener
- Only if needed
- Spirit
- None
- Alcohol
- Alcohol-free
Watermelon Martini
- Fruit or herb
- Four cubes of watermelon, muddled
- Citrus
- 15ml lime
- Sweetener
- Up to 10ml simple syrup
- Spirit
- 50ml vodka
- Alcohol
- Contains alcohol
Virgin Mojito
- Fruit or herb
- Ten mint leaves
- Citrus
- 25ml lime
- Sweetener
- 20ml simple syrup
- Spirit
- None
- Alcohol
- Alcohol-free
| Drink | Fruit or herb | Citrus | Sweetener | Spirit | Alcohol |
|---|---|---|---|---|---|
| Watermelon Cooler (ours) | 150ml watermelon juice, strained | 25ml lime | Only if needed | None | Alcohol-free |
| Watermelon Martini | Four cubes of watermelon, muddled | 15ml lime | Up to 10ml simple syrup | 50ml vodka | Contains alcohol |
| Virgin Mojito | Ten mint leaves | 25ml lime | 20ml simple syrup | None | Alcohol-free |
How to Serve It
In a tall glass packed with ice, with a small wedge of watermelon on the rim and a sprig of mint slapped once between the palms and stood beside it. Serve it straight away, while the soda is lively. For a jug, mix the juice and lime ahead and top each glass with soda as it goes out.
For a spirit drink on the same fruit, a Watermelon Martini; for mint, lime and soda with no alcohol, a Virgin Mojito.
Make it at home
More to explore
Frequently Asked Questions
Is the Watermelon Cooler alcohol-free?
What is in a Watermelon Cooler?
Do I need to add sugar?
Can I make it in advance?
How do I pick a ripe watermelon?
Can I use shop-bought watermelon juice?
Can I add a spirit to it?
Sources.
Correct as of 19 October 2026.
- USDA FoodData Central, “Watermelon, raw (FDC ID 167765)” (national food composition database, public record of the entry: water 91.45 g and total sugars 6.2 g per 100 g).
You Might Also Like
Watermelon Martini
A Watermelon Martini is fresh watermelon shaken with vodka and lime: four cubes of ripe melon muddled to juice, then 50ml vodka, 15ml fresh lime juice and up to 10ml sugar syrup, shaken hard and fine strained into a chilled martini glass with a small wedge on the rim. Martini here describes the glass only. Difford’s Guide says the Watermelon Martini emerged in London in the 1990s as one of many fresh fruit martinis made at The Met Bar. We have found no source that names its creator. Another drink shares the name, made with watermelon liqueur; this one uses the fruit. The melon sets the sweetness, so taste it before measuring the syrup. A ripe summer melon may need none. Expect about 2.0 UK units in each glass.
Virgin Mojito
A Virgin Mojito is ten mint leaves pressed gently with 25ml fresh lime juice and 20ml simple syrup in a highball, packed with crushed ice and topped with 120ml of soda water, then finished with a slapped mint sprig and a lime wheel. It contains no alcohol, so there are no units to count. It is the Mojito with the rum left out and the build kept whole. The Mojito’s flavour sits in mint, lime, sugar and soda, so taking out the rum costs it warmth and a little body rather than its character. Against the Mojito, syrup replaces the two teaspoons of sugar, because it mixes into cold lime at once, and the lime rises from 20ml to 25ml to keep the longer soda pour sharp.
Where this one sits
Recipe by Jerry Can Spirits · Updated 19 October 2026