Quick Recipe Version (TL;DR)
Quick Ingredients
- Water: 1 cup (240 ml)
- Granulated sugar: 3/4 cup (150 g)
- Pineapple juice: 1/2 cup (120 ml)
- Lime zest: 1 tsp (from 1–2 limes)
- Fresh lime juice: 2 tbsp (plus 1 tbsp to finish)
- Coconut extract: 1/4 tsp (or coconut water: 2 tbsp)
- Blue curaçao syrup (non-alcoholic): 1 tbsp, or 3–4 drops blue food color + 1/8 tsp orange extract
- Citric acid: 1/4 tsp (optional, for extra pop)
- Fine salt: pinch (about 1/16 tsp)
- Ice: 6 cups (about 720 g)
- Chilled club soda or lemon-lime soda: 3 cups (720 ml)
- Lime wedges and coarse sugar or Tajín for garnish (optional)
Do This
- 1. Simmer water, sugar, pineapple juice, and lime zest over medium heat until just bubbling, 2–3 minutes.
- 2. Off heat, stir in lime juice, coconut extract, citric acid, salt, and blue syrup (or color + orange extract). Steep 5 minutes.
- 3. Strain, chill syrup to 40°F/4°C (ice bath ~10 minutes).
- 4. Blend: 6 cups ice + 1 cup cold syrup + 3 cups very cold soda, 20–30 seconds until slushy.
- 5. Taste: add 1–2 tsp lime juice for brightness or a splash of soda if too thick.
- 6. Pour into chilled glasses, garnish with lime, and serve immediately.
Why You’ll Love This Recipe
- That signature neon tropical-lime flavor and color, right from your kitchen.
- Light, fluffy slush texture that sips just like a frozen fountain favorite.
- Easy make-ahead syrup means frosty freezes in minutes anytime.
- Adjustable sweetness and tartness so it’s perfect for your taste.
Grocery List
- Produce: 2–3 limes
- Dairy: None
- Pantry: Granulated sugar, pineapple juice (canned is fine), coconut extract (or coconut water), blue curaçao syrup (non-alcoholic) or blue food coloring + orange extract, citric acid (optional), club soda or lemon-lime soda, fine salt
Full Ingredients
Tropical-Lime Soda Syrup (makes ~1 cup)
- Water: 1 cup (240 ml)
- Granulated sugar: 3/4 cup (150 g)
- Pineapple juice: 1/2 cup (120 ml)
- Lime zest: 1 tsp, packed
- Fresh lime juice: 2 tbsp (30 ml)
- Coconut extract: 1/4 tsp (or coconut water: 2 tbsp)
- Blue curaçao syrup (non-alcoholic): 1 tbsp (15 ml), or 3–4 drops blue food coloring + 1/8 tsp orange extract
- Citric acid: 1/4 tsp (optional, boosts tang if using club soda)
- Fine salt: pinch (about 1/16 tsp)
Slush & Finish
- Ice: 6 cups (about 720 g; crushed if possible)
- Very cold club soda or lemon-lime soda: 3 cups (720 ml)
- Fresh lime juice: 1 tbsp (15 ml), to brighten right before serving
Optional Garnishes
- Lime wedges or wheels
- Coarse sugar or Tajín for rimming glasses
- Wide straws

Step-by-Step Instructions
Step 1: Simmer the tropical base
In a small saucepan, combine the water, sugar, pineapple juice, and lime zest. Set over medium heat and stir until the sugar dissolves. Bring just to a gentle simmer (about 200°F/93°C) and hold it there for 1–2 minutes; do not hard-boil. This infuses the citrus and pineapple without dulling the flavors.
Step 2: Finish, tint, and chill the syrup
Remove from heat and stir in the lime juice, coconut extract (or coconut water), pinch of salt, citric acid (if using), and blue curaçao syrup (or blue food color plus orange extract). Let steep 5 minutes. Strain through a fine-mesh sieve to remove zest. Transfer to a jar and chill to about 40°F/4°C; an ice bath takes roughly 10 minutes, or refrigerate until cold.
Step 3: Get everything frosty
For the fluffiest slush, pre-chill your soda until very cold (ideally 38°F/3°C). Pop your blender jar and four serving glasses in the freezer for 10 minutes while the syrup chills. If you like a rim, swipe glass rims with a lime wedge and dip in coarse sugar or Tajín before chilling.
Step 4: Blend the neon slush
Add to the blender: 6 cups ice, 1 cup cold syrup, and 3 cups very cold club soda or lemon-lime soda (pour soda last to limit foaming). Blend on low 5 seconds, then high for 20–30 seconds until the ice is finely crushed and the mixture looks like pourable, soft snow. If your blender is smaller than 64 oz, blend in two batches (half the amounts each time).
Step 5: Dial in flavor and texture
Taste. For more brightness, add 1–2 teaspoons fresh lime juice and pulse. If it’s too thick, blend in 2–3 tablespoons more soda. Want a more Baja-style teal? Add 1 drop blue coloring, or 1 tiny drop yellow to shift from blue to aqua, and pulse briefly.
Step 6: Serve immediately
Divide among chilled glasses. For a fountain-style finish, top each glass with a 1 tablespoon splash of soda to create light foam on the surface. Garnish with a lime wheel and serve with wide straws.
Pro Tips
- Colder ingredients mean fluffier slush. Keep the syrup and soda well-chilled and briefly chill your blender jar.
- Crushed or nugget ice blends smoother than big cubes. If using large cubes, pulse first to break them down.
- Freeze some syrup or soda into ice cubes to keep later batches vivid and less diluted.
- Pour soda into the blender last and vent the lid slightly to reduce foaming.
- Don’t over-blend; 20–30 seconds is plenty or the slush thins out.
Variations
- Mountain Dew Version: Swap the 3 cups club soda for 3 cups chilled Mountain Dew. Skip the citric acid and reduce the syrup sugar to 2/3 cup (133 g) to balance sweetness.
- Zero-Sugar: Make the syrup with 3/4 cup (150 g) allulose instead of sugar (it stays smooth) and use diet lemon-lime soda. Sweetness may need a small extra splash to taste.
- Adults-Only (21+): Stir 1 oz white or coconut rum into each glass just before serving. Note: Alcohol softens the slush; use a light hand.
Storage & Make-Ahead
The tropical-lime syrup keeps 2 weeks in the refrigerator or up to 3 months in the freezer (freeze in ice cube trays for quick portions). The finished slush is best right away. For leftovers, freeze in a shallow container; to serve, let sit at room temperature 10–15 minutes and scrape with a fork to granita, or briefly pulse in a blender with a splash of soda.
Nutrition (per serving)
Approximate for the club soda version: 175 calories; 44 g carbohydrates (about 41 g sugars); 0 g fat; 0 g protein; 35 mg sodium. Using lemon-lime soda adds roughly 70–90 calories and 18–24 g carbs per serving, depending on brand.

