Clean, wash and cut the rhubarb into pieces. Sort the raspberries. Boil up sugar and 2 litres of water in a pot. Add the rhubarb and raspberries and cook for about 30 minutes. Strain fruits through a sieve. Collect the stock. Squeeze the rhubarb remains with a ladle
Reduce the brew to approx. 750 ml (depending on pot size 30-40 minutes). Put star anise in a tea filter. Halve the lemon and squeeze. Add lemon juice and tea filter approx. 10 minutes before the end of cooking time. Take out tea filter. Take the pot off the stove and let it cool down a little. Pour the syrup, still hot, into a prepared, sterilized bottle and let it cool down
Tastes great in ice-cold mineral water or sparkling wine, for example. Mixing ratio according to taste 2-3 tbsp. syrup to 300 ml water or sparkling wine