Quick Recipe Version (TL;DR)
Quick Ingredients
- 2 cups (480 ml) water
- 1 cup (200 g) granulated sugar
- 2 tablespoons (42 g) light corn syrup
- 1/4 teaspoon citric acid (or 1 tablespoon / 15 ml bottled lemon juice)
- 1/8 teaspoon xanthan gum (optional, for finer “micro-crystal” texture)
- Blue Raspberry option: 1 teaspoon blue raspberry flavoring (water-soluble) + 2 to 4 drops blue food coloring
- Cola option: 1 tablespoon cola extract (or 3/4 cup / 180 ml cola fountain syrup)
- 2 cups (480 ml) ice-cold club soda, seltzer, or sparkling water (refrigerated to 34–38°F / 1–3°C)
Do This
- 1. Simmer water + sugar + corn syrup 2 minutes; remove from heat.
- 2. Whisk in citric acid (and xanthan if using), then add flavoring/color.
- 3. Chill syrup to 40°F / 4°C, then pour into a shallow pan.
- 4. Freeze 4 hours, scraping once halfway, until solid and frosty.
- 5. Break frozen slab into chunks; briefly pulse in a blender to snow.
- 6. Add ice-cold club soda; pulse 5–10 seconds to keep micro-crystals and some fizz.
- 7. Serve immediately with a wide straw; adjust thickness with more frozen base if needed.
Why You’ll Love This Recipe
- Ultra-fine, sippable ice crystals (not chunky shaved ice) with an easy freezer-and-blender method.
- Bright, classic convenience-store flavors: Blue Raspberry or Cola.
- Uses carbonated liquid at the end for a “frozen soda” vibe without special equipment.
- Flexible sweetness and tang so you can match your favorite Slurpee intensity.
Grocery List
- Produce: 1 lemon (optional, if using fresh lemon juice instead of citric acid)
- Dairy: None
- Pantry: granulated sugar, light corn syrup, citric acid (or bottled lemon juice), xanthan gum (optional), blue raspberry flavoring (water-soluble) and blue food coloring (for Blue Raspberry) or cola extract/cola fountain syrup (for Cola), club soda/seltzer/sparkling water
Full Ingredients
Master Slurpee Syrup Base (makes about 2 1/4 cups / 540 ml concentrate)
- 2 cups (480 ml) water
- 1 cup (200 g) granulated sugar
- 2 tablespoons (42 g) light corn syrup (helps keep crystals tiny and “sippable”)
- 1/4 teaspoon citric acid (preferred for a clean, candy-like tang) or 1 tablespoon (15 ml) bottled lemon juice
- 1/8 teaspoon xanthan gum (optional, helps prevent ice from separating and keeps the slush smoother)
Choose Your Flavor
- Classic Blue Raspberry: 1 teaspoon water-soluble blue raspberry flavoring + 2 to 4 drops blue food coloring
- Classic Cola: 1 tablespoon cola extract or 3/4 cup (180 ml) cola fountain syrup (from a soda-syrup bottle)
To Blend and Serve (adds “frozen carbonated” character)
- 2 cups (480 ml) club soda, seltzer, or sparkling water, ice-cold (34–38°F / 1–3°C)
- Optional: 1 to 2 tablespoons (15–30 ml) extra chilled syrup base (for a sweeter, more intense flavor)
Step-by-Step Instructions
Step 1: Set up your freezing pan and chill your tools
Place a metal 9 x 13-inch pan (or any shallow, freezer-safe pan) in the freezer to pre-chill for 10 minutes. If possible, also place your blender jar in the refrigerator for 15 minutes (a cold jar helps keep crystals tiny instead of melting into a watery slush).
Make sure your club soda/seltzer is fully chilled to 34–38°F (1–3°C). Warm carbonation goes flat quickly and melts the slush.
Step 2: Cook the syrup base for smooth texture
In a small saucepan, combine 2 cups (480 ml) water, 1 cup (200 g) sugar, and 2 tablespoons (42 g) light corn syrup. Set over medium heat and stir until the sugar dissolves completely.
Once it reaches a gentle simmer, cook for 2 minutes. You’re not trying to thicken it a lot; you’re just fully dissolving sugar and building a smoother base that freezes into finer crystals.
Remove from heat.
Step 3: Add tang and (optionally) micro-crystal insurance
Whisk in 1/4 teaspoon citric acid (or 1 tablespoon / 15 ml bottled lemon juice) until dissolved.
If using xanthan gum, sprinkle in 1/8 teaspoon while whisking constantly for 20 seconds. (Sprinkling prevents clumps.) Let the syrup sit for 2 minutes, then whisk again. The syrup may look slightly thicker; that’s normal.
Step 4: Flavor it Blue Raspberry or Cola
For Blue Raspberry: Whisk in 1 teaspoon blue raspberry flavoring, then add 2 to 4 drops blue food coloring. Aim for a bright “electric” blue. Blue intensifies when frozen, so stop just shy of your final desired color.
For Cola: Whisk in 1 tablespoon cola extract. If using cola fountain syrup instead, whisk in 3/4 cup (180 ml) and reduce the cook time in Step 2 to exactly 1 minute (fountain syrup is already concentrated).
Step 5: Chill, then freeze into a thin slab
Pour the syrup into a heatproof container and chill in the refrigerator until it reaches 40°F / 4°C, about 30 minutes. (Cooling first reduces freezer steam and helps it freeze evenly.)
Pour the chilled syrup into your pre-chilled shallow pan. Freeze uncovered for 2 hours.
After 2 hours, scrape firmly with a fork (or metal spoon) to break up the forming ice and encourage smaller crystals. Return to the freezer and freeze 2 more hours, or until fully frozen and opaque.
Step 6: Make “snow” first, then add carbonation quickly
Remove the pan from the freezer and let it sit at room temperature for exactly 3 minutes (this makes it easier to break into chunks without melting too much).
Break the frozen slab into 2-inch pieces. Add the pieces to a blender.
Pulse to snow: Pulse 10 to 12 times (about 1 second each). You want fluffy, tiny ice bits before you add carbonation.
Add fizz carefully: Pour in 2 cups (480 ml) ice-cold club soda/seltzer. Do not fill the blender more than halfway; carbonated liquid can foam up. Place the lid on loosely at first, then secure it.
Pulse just 3 to 5 times (about 1 second each), then stop. Over-blending warms the mix and knocks out bubbles.
Step 7: Fine-tune thickness and serve like the real deal
Check the texture. You’re aiming for a thick, pourable slush that still sips through a wide straw.
- If it’s too thick: add 2 tablespoons (30 ml) more ice-cold club soda and pulse once.
- If it’s too thin: add a handful of frozen chunks from the pan (or 1 cup / 140 g ice) and pulse 1 to 2 times.
- If you want it more intense: add 1 to 2 tablespoons (15–30 ml) extra chilled syrup base and pulse once.
Pour into chilled cups and serve immediately with wide straws. For the most “machine-like” feel, let the blended slush sit for 60 seconds in the freezer, then stir and serve.
Pro Tips
- Use corn syrup for smaller crystals: It reduces large, crunchy ice shards and makes the slush feel smoother and more “sippable.”
- Keep everything cold: Chill the syrup to 40°F / 4°C before freezing, and use carbonated water at 34–38°F / 1–3°C. Warm ingredients melt the micro-crystals fast.
- Pulse, don’t blend: Continuous blending warms the mixture and flattens carbonation. Short pulses keep the slush bright, icy, and airy.
- Shallow pan beats ice cubes: A thin slab breaks into flakes that blend into finer crystals than chunky cubes.
- Wider straw matters: A standard soda straw clogs. Use a smoothie straw for the closest experience.
Variations
- Blue Raspberry Lemonade: Replace the club soda with ice-cold lemon-lime soda (same 2 cups / 480 ml). Reduce citric acid to 1/8 teaspoon to avoid over-tartness.
- Cherry-Cola: Make the Cola version and add 1/4 teaspoon cherry extract (or 1 tablespoon / 15 ml cherry syrup) to the syrup base in Step 4.
- Extra-sour “gas station” style: Increase citric acid to 3/8 teaspoon total (add the extra 1/8 teaspoon in Step 3). The flavor pops more, especially in Blue Raspberry.
Storage & Make-Ahead
Make-ahead: The frozen slab can be made up to 7 days ahead. Keep it covered once fully frozen (wrap the pan tightly or transfer broken pieces to a zip-top freezer bag) to prevent freezer odors.
After blending: This is best immediately. If you must hold it, put the blended slush in the freezer for up to 30 minutes, stirring once halfway. Expect it to lose some carbonation and become slightly icier.
Nutrition (per serving)
Approximate, based on 4 servings and using club soda: 210 calories; 0 g fat; 0 g protein; 54 g carbohydrates; 54 g sugar; 10 mg sodium.
