Iced Cascara (or Kaffeine's RedBull)

Cascara is a dried berry shell from coffee beans and currently a raging novelty in most serious coffee house's. I say novelty now but I'm pretty sure it will grow to be as popular as dare I say TEA! Usually served in teapots and left to brew for several minutes in hot water, much the same as tea but more potent in caffeine.
James the lead barista at Kaffeine asked me to come up with some sort of cascara based drink he could serve chilled during London's warmer months. I instantly thought cola or red bull but with less tooth decaying ingredients. We sampled 2 different cascara from El Salvador and settle on a variety that had a slight smoky and lingering fieriness to it but ultimately cooling thanks to the watermelon, lime and mint in the syrup. Best served with loads of ice and sparkling water on a stifling hot day to pick one's self up.       
60g cascara
1 watermelon
2 bramley apples
4 limes
750ml apple juice
1/2 bunch mint
3 cardamon pods
2 dried red chillies
125g sugar
Sparkling water to serve

METHOD:
Cut watermelon in half, remove the rind and discard, slice melon into 5cm cubes and put in large heavy based pot. Cut apples and limes into quarters and add to pot along with cascara, apple juice, mint, cardamon and dried chillies. Place pot over a medium heat and cook for 2 hours stirring once and a while to prevent sticking.
Place a large fine strainer (if your stainer isn't fine line with muslin cloth) over bowl and pour in cascara liquid, with the back of a large spoon press down on the sediment squeezing out any excess liquid. Put the cascara syrup back in a clean pot and add sugar, place pot over medium heat and cook for 20 minutes. Leave syrup to cool at room temperature then move into a 1ltr bottle and store in fridge.
To make a drink fill glass with ice cubes and pour in 50ml of syrup (around 3 tablespoons), add 250ml of sparkling water and stir.