Add the Aronia berries, sugar and water to a non-reactive saucepan. Bring to a simmer over medium heat and simmer until the berries burst. Simmer until syrup is reduced to half. Strain syrup through a fine mesh strainer. Allow to cool before use.
Make the Aronia Gin Cocktail
Fill a shaker with ice. Measure the Aronia syrup, lemon juice and gin into the shaker. Cover and shake the cocktail hard for 15-30 seconds, then strain into a chilled cocktail glass. Serve immediately.