Combine equal parts granulated sugar and water (e.g., 200 ml water and 200 g sugar) in a small saucepan. Heat gently, stirring, until the sugar dissolves completely. Do not boil. Cool to room temperature. Measure out 200 ml for the recipe.

In a clean mixing bowl or jar, combine the 200 ml simple syrup with 60 ml cola concentrate (if using) to add cola backbone and color. Stir to combine.

Add 20 ml cherry syrup (or grenadine), 15 ml black cherry or prune concentrate, 1 tsp vanilla extract, 1 tsp almond extract, and 1/4 tsp rum extract. Stir thoroughly so the flavors integrate.

Add 5 ml fresh lemon juice and 2 tsp of a mild citric acid solution (or a small squeeze of lime) to provide brightness and acidity. Stir and taste; adjust acidity a little if necessary—Dr Pepper is slightly tangy but balanced.

If you want a darker appearance like the commercial soda, add 2 drops of caramel color and stir. Cover the syrup and refrigerate for 30 minutes to let flavors marry (this can be longer, up to several hours).

Assembling the Soda

Chill a tall glass and/or the carbonated water. Fill the glass with about 1 cup of ice (or to preference).

Measure 200 ml of the prepared flavored syrup and pour it over the ice.

Slowly pour 1 liter of chilled carbonated water into a large pitcher or directly into the glass over the syrup to preserve carbonation. If using a pitcher, gently stir once with a long spoon to combine — avoid vigorous stirring which will flatten the soda.

Taste and adjust: if the soda is too sweet, add a little more carbonated water; if it needs more fruitiness, add 5–10 ml cherry syrup; if it needs more lift, add a few drops more lemon or citric acid solution.

Serve immediately garnished with a maraschino or fresh cherry and a lemon/lime wedge on the rim. Optionally, give a small stir before drinking to fully mix flavors.