Frozen Watermelon Agua Fresca
A refreshing Mexican frozen beverage made from fresh watermelon, sweetened with a light sugar syrup, brightened with lime juice, and enhanced with a subtle hint of salt. Serve as a slushy drink, freeze into popsicles, or churn into granita ice. Perfect for hot summer days.
- Prep
- 15 min
- Cook
- 5 min
- Wait
- 10 min
- Total
- 30 min
- Makes
- About 1½ quarts (1.4 L), serves 6
Steps
Before you start
- Freeze watermelon chunks for at least 2 hours ahead, or freeze overnight
- Have fresh limes at room temperature for easier juicing
- Chill serving glasses in the refrigerator if serving as slushy
- Gather all ingredients and equipment before starting
Make simple syrup
- In a small saucepan, combine 1 cup (240 ml) water and 3/4 cup (150 g) sugar.
- Heat over medium heat, stirring constantly until the sugar dissolves completely, about 2-3 minutes.
- Do not let it boil rapidly.
- Remove from heat and set aside to cool to room temperature.
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Ready when: Sugar is fully dissolved with no visible granules; syrup is clear
Tip: To speed cooling, place the saucepan in an ice bath for 5 minutes
Blend frozen watermelon
- Add 4 lbs (1800 g) frozen watermelon chunks to a blender along with the cooled simple syrup, 1/2 cup (120 ml) fresh lime juice, and 1/4 teaspoon (2 g) salt.
- Blend on high speed for 2-3 minutes until completely smooth and slushy.
- If the mixture is too thick to pour or blend smoothly, add cold water in 1/4 cup (60 ml) increments and blend again until pourable.
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Ready when: Mixture is completely smooth, creamy, and slushy; no chunks of watermelon remain visible
Tip: If your blender struggles with frozen watermelon, work in two batches or let it thaw for 5 minutes first
Strain the mixture
- Pour the blended mixture through a fine mesh strainer into a large pitcher, gently pressing the solids with the back of a wooden spoon to extract all the liquid.
- Discard the pulp and seeds.
- You should have about 1.5 quarts (1.4 L) of strained agua fresca.
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Ready when: All liquid has been strained into the pitcher; solids are thoroughly drained
Tip: Don't press too aggressively or pulp will push through the strainer; gentle pressure is sufficient
Serve immediately
- Pour the agua fresca into chilled glasses, filling about three-quarters full.
- Add ice cubes and garnish with fresh lime slices or mint sprigs.
- Serve immediately with a spoon or thick straw, as the mixture will gradually separate and melt.
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Tip: Serve immediately while the drink is frosty; the frozen watermelon keeps it naturally slushy for 10-15 minutes
Good to know
Tips
- Choose a ripe, sweet watermelon for the best flavor; the natural sweetness means you can reduce the sugar to 1/2 cup (100 g) if preferred
- Don't skip the salt; even 1/4 teaspoon of salt amplifies the watermelon flavor and balances the sweetness beautifully
- For a creamier, more dessert-like version, blend in 1/4 cup (60 ml) of coconut milk or heavy cream before straining
- If serving as popsicles, let the mixture partially freeze in the molds for 1-2 hours before inserting sticks so they stand upright
Make ahead
The agua fresca base can be made up to 3 days ahead and stored in a covered pitcher in the refrigerator. Stir well before serving, as the mixture may separate slightly. Alternatively, pour the strained mixture into popsicle molds and freeze for 4-6 hours to make frozen treats. Or pour into a shallow 9x13-inch baking pan and freeze for 2 hours, then scrape with a fork every 30 minutes to create a granita-style frozen dessert.
Storage & reheating
Room temperature: up to 1 hour before it starts to melt. Refrigerator: up to 3 days in a covered pitcher; stir before serving. Freezer: up to 1 month as popsicles (wrapped individually) or granita (stored in a freezer bag); thaw at room temperature for 10 minutes before serving.
Substitutions
- Fresh watermelon → Cantaloupe or honeydew melon. Use equal weight; these melons are less juicy, so you may need to reduce the water by 1/4 cup (60 ml) to avoid a watery drink
- Fresh lime juice → Fresh lemon juice. Use the same amount (1/2 cup / 120 ml); add an extra 1/4 teaspoon (2 g) of sugar to balance the acidity
- Granulated sugar → Honey or agave nectar. Reduce to 1/2 cup (120 ml) honey or 6 tablespoons (90 ml) agave, as these sweeteners are more concentrated than sugar
- Water → Coconut water or fresh pineapple juice. Use equal amount (1 cup / 240 ml) for a tropical twist; reduce sugar to 1/2 cup (100 g) if using pineapple juice
