2kg/4½lb/9 cups sugar
75g/3oz citric acid
2 unwaxed lemons, sliced
20 fresh elderflower heads, shaken and stalks trimmed
1 Put the sugar and 1.2 litres/2 pints/5 cups water in a pan. Heat gently without boiling, stirring until the sugar dissolves.
2 Bring to the boil and then remove from the heat.
3 Stir in the citric acid, lemon slices and elderflowers. Cover the pan and leave to infuse overnight or for up to 24 hours.
4 Pass the liquid through a sieve lined with muslin (cheesecloth) into a bowl. Pour into sterilized bottles and store in the fridge