Pour water into a medium saucepan and add 2 cups of granulated sugar. Heat the water and sugar mixture on the stovetop (stirring often) until it has reached the "almost boiling" point. Once all sugar has dissolved, remove the pan OFF the heat source. Let liquid cool COMPLETELY.

Once liquid is completely cool, add vodka and peppermint extract. **If using, add 6 drops of green food coloring, as well. The crème de menthe will taste exactly the same with or without the green color. Stir until these ingredients have been fully combined with the water and sugar mixture.

Place a funnel (or measuring cup with a spout) into the mouth of the bottle. TIP: It's helpful to place the empty bottle in the sink first, in case you spill any liqueur! Carefully pour the liqueur through the funnel and into the jar. Fill bottle to the top, then add a tight-fitting lid. Repeat with additional bottles, as needed.

Wipe jars clean with a wet cloth or paper towel, so any drips don't make the jars sticky! Label each jar (especially if the liqueur is CLEAR), so you'll remember what's in it! Store homemade creme de menthe in a dark pantry (to help prevent evaporation). Enjoy!