Mint soak in water for a few minutes and rinse well under running water.
Pour water, bring to a boil and simmer for 15 minutes. Remove.
Add to mint broth sugar, a slice of lime, citric acid and cook stirring over medium heat for 10 minutes.
Syrup cool, strain, add vodka and mix well, you can add a fresh sprig of mint to the bottle, which is removed after 5 days (for a more pronounced taste ).
For a brighter color, you can add food coloring.
I preferred to keep the natural color.