Mountain Dew Recipe

Make simple citrus syrup

In a small saucepan, combine the granulated sugar with 2 tablespoons of water (not in the ingredients list separately because water comes from the carbonated water volume) over low heat. Stir constantly until the sugar fully dissolves and you have a clear syrup (about 2–3 minutes). Remove from heat and let cool for 5 minutes.

Mix citrus and flavorings

Into a tall mixing glass or pitcher, add the cooled simple syrup. Stir in the fresh lime juice, fresh lemon juice, and orange juice. Add the citrus extract (or concentrate) and vanilla extract, then sprinkle in the citric acid. Stir until the citric acid dissolves.

Color and optional caffeine

Add 2 drops yellow food coloring and 1 drop green food coloring to the flavored syrup mixture and stir until the color is uniform. If using food-grade powdered caffeine, dissolve it into a teaspoon of warm water or a small amount of the syrup and mix thoroughly, then incorporate into the syrup mixture (use caution — 20 mg is roughly one-fifth of a typical tablet and measure carefully).

Combine with carbonated water

Fill a serving glass with ice (about 1 cup). Pour 2 cups of cold carbonated water into the pitcher with the syrup and gently fold to combine — avoid stirring vigorously to preserve carbonation. Alternatively, pour the syrup over the ice in the glass and top with the carbonated water, stirring gently once with a spoon.

Adjust sweetness and acidity

Taste the soda. If you want it sweeter, add up to 1 teaspoon high‑fructose corn syrup or simple syrup and stir gently. If you prefer more tang, add a small pinch (about 1/8 tsp) more citric acid or another 1/2 teaspoon citrus juice and mix gently. Adjust color with an extra drop of yellow if desired.

Serve

Garnish with a lime wedge on the glass rim if desired. Serve immediately while cold and fizzy.

For a more authentic commercial sweetness, replace part or all of the granulated sugar-based syrup with high-fructose corn syrup (measure to taste). To make a larger batch, multiply all ingredients proportionally. Always label any caffeinated homemade soda and keep out of reach of children.