Put raspberries in bowl and break apart with fork.
Stir in vinegar and refrigerate.
Next day stir in half the sugar and return to refrigerator.
Third day strain through cheesecloth or very fine sieve.
Measure juice and add 2 oz brandy for each cup of juice.
Bottle and keep refrigerated.
To serve: Pour 1/3 cup of syrup over ice cubes and fill with soda water.