Puree the apple compote and mix 4 tablespoons of it with apple juice. Stir the remaining apple compote with kefir, lemon juice, sugar, cinnamon and syrup until smooth and chill for about 1 hour. Pour apple mixture into 4 glasses and pour on the kefir mixture.
Garnish with lemon wedges and lemon balm, if desired, and serve with straws.