Wash the lime with hot water and cut into thin slices with the ginger. Bring to the boil together with the raspberries with 125 ml water over medium heat, then remove from the stove and let steep for 30 minutes.
Pass the juice through a sieve, pour into a saucepan and just bring to the boil. Pour the hot juice into a sterilized bottle, close it immediately and let it cool. The juice stays sealed in the refrigerator for about two weeks.
If desired, fill up with ice cubes and mineral water before serving.