Butterbeer is a popular beverage in the wizarding world. Tastes as butterscotch although there are some variants brewed.
It's sold at The Three Broomsticks and The Hog's Head in Hogsmeade and the Leaky Cauldon in the Diagonal Alley. The Students of Hogwarts School of Witchcraft and Wizardry often buy it when visiting Hogsmeade.
The butterbeer could be served cold in bottles and hot in "foaming tankards”.