Diet Pepsi Recipe

Chill the carbonated water thoroughly so the drink retains maximum fizz. Use filtered water that has been carbonated to about 2.5–3.0 volumes of CO2 if using a home soda maker.

Place 4 ice cubes into a 16 oz (approximately 475 ml) glass if you prefer a chilled serve; otherwise skip ice to preserve carbonation longer.

Measure and combine concentrates

Add 1.25 oz (approx. 2 1/2 tablespoons) of cola syrup to a small measuring cup. If you are using a commercial cola concentrate designed for dilution, follow its recommended ratio; the listed amount is for a 12 oz serving.

Add 0.5 tsp liquid zero-calorie sweetener (adjust to taste). If using powdered sweetener, dissolve it first in a teaspoon of warm water before adding.

Stir in 0.25 tsp citric acid solution or one small squeeze (about 1/4 tsp) of fresh lemon juice to add brightness and the mild acidic bite characteristic of cola.

Add approximately 0.1 tsp of a cola flavor blend (a few drops of vanilla extract + a tiny pinch of ground cinnamon and an orange or lime oil drop if available). This provides the aromatic top notes. Mix the flavor components into the cola syrup until uniform.

Taste the concentrate: it should be noticeably sweet and strongly flavored (concentrated). Adjust sweetness or acidity now: add an extra 1/8–1/4 tsp sweetener or a drop more lemon juice if needed.

Pour the prepared cola-flavor concentrate over the ice (if using) in the chilled glass.

Slowly add 12 oz chilled carbonated water down the side of the glass to minimize foaming. Pour gently while stirring slowly with a long spoon to combine the concentrate and carbonated water evenly without losing too much fizz.

Give the drink one gentle stir (3–4 rotations) to integrate. Do not over-stir to preserve carbonation.

Garnish with a lemon wedge on the rim or a thin slice dropped into the drink if desired.

Serve immediately with a straw. If storing, keep chilled and consume quickly to retain carbonation and flavor.