In a deep pan, add the jamuns and 2 cups of water and cook on high flame for about 10-12 minutes.
Once it looks pulpy, turn off the flame and let the liquid cool down. Now sieve the mixture with a thick sieve to just deseed it and let some pulp go down .
Now ,heat the pan again, pour the liquid and add sugar and cook till thick.This should take about 5-7 minutes only. Now add cumin powder and mix well
Turn off the flame and let it cool down a bit. Add the lemon juice and mix again.
Once the mixture is cooled completely, now add the lemon juice and bottle the mixture to store.You may keep this in the fridge for upto 6 months.
To prepare Jamun Juice/Sherbet
Pour 2 tbsp of the concentrate into the glass.
Add 4-5 cubes of ice and a sprig of mint(optional).