Rinse kokum with water and soak it in 2 cups of water for 2 hours.
Transfer the soaked kokum along with the water to a blender and blend to make a smooth paste.
Add the kokum paste to a pan along with sugar, the remaining 2 cups of water, cumin powder, ground cardamom, black salt, and black pepper powder. Mix well to combine.
Cook this mixture over medium-low heat for 25-30 minutes, stirring occasionally using a silicone or a wooden spatula.
Remove the pan from the heat and let the mixture cool down to room temperature.
Pass the mixture through a fine-mesh strainer. Press with the back of a spoon to get as much extract as possible. Discard the leftovers.
Store the kokum concentrate in the refrigerator in a glass bottle for up to 6 months. It is also freezer-friendly! You can freeze it for about a year in a freezer-safe ziplock bag or container. Thaw and use whenever required.
To make the sherbet, pour 3 tablespoons of kokum concentrate into a glass and top up with chilled water or club soda.
Note - Shake the concentrate well before using it.
Add a few ice cubes to the glass. Garnish with a mint sprig and serve chilled.
Video
Notes
Don't use salted kokum to make this sharbat.Kokum juice should taste refreshing and mildly tangy, never overly sour. If it tastes sharp, add more water, not more sugar, to balance it.