Add hibiscus flowers and water to a medium saucepan. Bring to a boil over medium-high heat.

Reduce heat and simmer for 15 minutes.

Remove from heat. Strain the liquid through a fine-mesh sieve or cheesecloth to discard flowers.

Measure the strained liquid. Return it to the pot and add an equal volume of sugar.

Heat gently, stirring until the sugar is fully dissolved. Do not boil.

Let the syrup cool to room temperature.

Pour into a sterilized glass jar or bottle and seal tightly.

Store in the refrigerator for up to 1 month.