Dark berry lemonade

Dissolve the sugar in the lime juice, pour in the berry juice and sparkling water, add the drops and stir once. Add the blackberries and ice and leave to infuse for ten minutes. The lemonade stays dark and only turns cold on the palate: eucalyptus and mint come through behind the sweetness and turn a well-behaved berry lemonade into a grown-up drink. Five drops are a good start: taste first, then add more.