Lemonade

 was a common Earth beverage derived from lemons. It was made without alcohol. (AUDIO: Autumn) When the Tenth Doctor and Donna Noble visited Earth in 1926, the Doctor said that the air smelled of grass and lemonade with a hint of mint.

Lemonade as a drink
Lemonade was one of the ingredients in the Kandy Man's kitchen. The Seventh Doctor used it to stick the Kandy Man's feet to the floor of his kitchen. (TV: The Happiness Patrol)

The Seventh Doctor persuaded Ace to drink lemonade instead of Pat Rowlinson's homebrewed beer. (TV: Battlefield)

The Doctor drank lemonade on several occasions. (PROSE: Human Nature, PROSE: History 101)

The Pied Piper's realm had lemonade fountains. (COMIC: Challenge of the Piper)

The Eleventh Doctor claimed to have put a tap for lemonade in the kitchen of Uncle Digby's country estate. (TV: The Doctor, the Widow and the Wardrobe)

Lemonade's other uses
The Tenth Doctor destroyed the Glutonoid with a toxic mixture that was flavoured with, among other things, lemonade. (COMIC: The Glutonoid Menace)

Behind the scenes
Though never made clear in any Doctor Who story, lemonade is almost universally used in the British sense in the DWU. It refers to a lemony soda. Its closest American analogue is ®, rather than the non-carbonated, generally homemade, fresh-squeezed drink Americans call lemonade.