Lemonade

Lemonade was a common Earth beverage derived from lemons. It was made without alcohol. (BFA: Autumn)

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. (DW: The Happiness Patrol)

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

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

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

The Tenth Doctor destroyed the Glutonoid with a toxic mixture that was flavoured with, among other things, lemonade. (DWBIT: The Glutonoid Menace)

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

Behind the scenes
Thoguh 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.