When premium mixers firm Fever-Tree launched its IPO in late-2014, shares were priced at GBP1.34. Today, following the release of 2016's results, Fever-Tree's shares are trading at over GBP15. Late last month, just-drinks sat down with the company's founders, Charles Rolls and Tim Warrillow, who still own 21.8% of the company, to explore the reasons behind Fever-Tree's success.