Pepsi Recipe

Make citric acid solution

If using dry citric acid, dissolve 1/2 tsp citric acid in 1 tbsp (15 ml) water to make the citric acid solution called for in the recipe.

In a small measuring cup or bowl, combine the cola flavor concentrate (0.5 tsp), vanilla extract (1 tsp), and the prepared citric acid solution (1 tsp). Add fresh lime juice (0.25 tsp). Stir thoroughly until combined.

If using cold-brew coffee for added depth, stir in 0.25 fl oz (about 7 ml) now. Set the flavoring blend aside.

In a separate small container, combine the simple syrup (1.5 fl oz) and caramel color syrup (0.25 fl oz). Stir until uniform.

Pour the sweetener mixture into the combined flavoring blend and stir until fully incorporated. Taste a small sample (a teaspoon) to verify sweetness, acidity, and cola character; adjust by adding up to 0.25 fl oz more simple syrup for sweetness, or an extra 1/8 tsp citric acid solution for brightness, if desired.

Fill a tall glass with 1 cup of ice cubes.

Pour the chilled carbonated water (12 fl oz) gently into the glass over the ice, leaving a little room at the top (about 1/2 inch) to add the syrup without excessive fizzing.

Slowly pour the combined syrup and flavoring blend down the side of the glass so it sinks and mixes gradually with the carbonated water. Stir gently once with a bar spoon (1–2 turns) to marry flavors while preserving carbonation.

Taste and adjust: if you want it sweeter, add up to 0.25 fl oz more simple syrup and stir once; if you want more tang, add an extra 1/8 tsp citric acid solution and stir gently.

Garnish with a lime wedge on the rim, if desired. Serve immediately cold.

If preparing multiple servings, scale all ingredients proportionally and keep the carbonated water chilled and syrup chilled/sealed until ready to combine to maintain fizz.