Sherry is a fortified wine from Spain.
Sherry was the alcoholic drink of choice of Professor Trelawney. She would even drink cooking sherry, and she sometimes smelled strongly of it (OP25, OP26, HBP10, HBP15, HBP25). Trelawney drank quite a lot of sherry, and placed the empty bottles in the Room of Requirement (HBP25).
Dolores Umbridge likes a glass of sweet sherry, although she then becomes “prone to spout very uncharitable views”, shocking even other wizards with anti-Muggle views (Pm).
Sherry is a fortified wine made from grapes and comes from Jerez in the Andalusia region of Southern Spain (Wikipedia).
Cooking sherry has extra salt added to it (for extended shelf life) (Masterclass).
From the Web
Writing by J K Rowling on WizardingWorld.com (Pottermore):
WizardingWorld.com (Pottermore) features:
Harry Potter Wiki: Sherry