Red Grape and Mint Sorbet

1kg seedless red/black grapes
3 Tbs castor sugar
1 cup red grape juice
2 Tbs fresh mint
Remove the grapes from the stems, then place onto a tray (this will help them freeze faster). Place the tray into the freezer for 2 hours or until the grapes are completely frozen.
Place the frozen grapes, castor sugar, grape juice and mint into a food processor, then blend until pureed.
Scoop and serve immediately or transfer to a freezer safe container and freeze until ready to use.