Fever Tree's soda water is made with natural spring water and has lots of bubbles - exactly what you need to bring out the finest points of a good whisky. Also great in cocktails and mocktails alike. About Fever Tree: "Following a 'tonic tasting' in 2000 to find the best on the U.S. market, Charles Rolls--who had built his reputation running Plymouth Gin--joined forces with Tim Warrillow, who had a background in luxury food marketing, to analyze the composition of mixers. The pair discovered that the majority of mixers were preserved with sodium benzoate or similar substances, while the use of cheap orange aromatics such as decanal and artificial sweeteners (such as saccharin) was widespread - a combination that was affecting the tasting experience and driving customers away from the sector. So, in 2004, they began creating mixers using natural and fresh ingredients. Fever-Tree Premium Indian Tonic Water launched in the UK in early 2005, the brand name chosen due to 'Fever Tree' being the colloquial name for the Cinchona Tree in which quinine, a key ingredient for tonic, is found."