Place 4 cups of cold filtered water in the refrigerator until well chilled (at least 30 minutes) if not already cold. Cold water holds carbonation better and results in a crisper sparkling water.

Carbonate the water

Using your soda siphon or sparkling water maker, follow the manufacturer's instructions to carbonate the chilled water. For medium fizz, use one standard CO2 cartridge or the device's medium setting. If using a countertop sparkling machine with adjustable levels, set to medium. If you prefer very fizzy water, increase carbonation one step.

Optional Flavor & Garnish (choose as desired)

Prepare garnishes

Rinse any fresh fruit, herbs, or cucumber. Thinly slice lemon, lime, or cucumber. Lightly bruise mint leaves by clapping them between your palms to release aroma. If using berries, give them a quick rinse and pat dry.

Add flavor (cold infusion)

Place chosen garnishes (lemon or lime slices, cucumber slices, berries, and/or mint) into the serving glass. If you want a hint of sweetness, add 1 tsp simple syrup to the glass. Do not overfill the glass; leave room for sparkling water and ice.

Combine with sparkling water

Slowly pour the carbonated water into the prepared glass over the back of a spoon or down the side of the glass to minimize lost effervescence. Pour until the glass is about 90% full, leaving a small headspace.

Adjust and serve

Taste and adjust: add another slice of citrus for stronger aroma, a few more mint leaves for herbal notes, or a dash more simple syrup for sweetness. Add ice if desired (note ice will dilute as it melts). Serve immediately to enjoy maximum fizz.

Serving

Garnish the glass rim with a lemon or lime wedge if desired and serve chilled. If preparing multiple servings, carbonate water in batches as needed and repeat garnish steps. Store leftover carbonated water in a sealed bottle in the refrigerator and consume within 24–48 hours for best fizz.