" . . . a few of you need to read Wanderings with Werewolves more carefully. I clearly state in chapter twelve that my ideal birthday gift would be harmony between all magic and non-magic peoples - though I wouldn't say no to a large bottle of Ogdens Old Firewhisky!"
-- Gilderoy Lockhart (CS6)
A strong alcoholic beverage similar to Muggle whiskey that burns the throat (OP5).
Gilderoy Lockhart hinted that he wanted students to buy him a bottle for his birthday (CS6).
When the Weasleys returned home after the Dark Mark appeared at the Ministry, Molly was nearly hysterical with worry so Arthur poured some Ogden's Old into her tea (GF10).
Ron thought Aberforth Dumbledore might sell them a bottle at the Hog's Head tavern while waiting for the meeting of Dumbledore's Army. Hermione felt a need to remind him that he was a Prefect (OP16).
Rita Skeeter poured a glass on herself in the Three Broomsticks while Hermione blackmailed her into writing a positive story about Harry for The Quibbler (OP25).
Someone named Harold Dingle wanted to sell the Gryffindors a bottle when O.W.L. Exams were over (OP32)
Romilda Vane gave Harry some Chocolate Cauldrons she said contained firewhisky, but they actually contained a love potion. Ron ate them and fell madly in love with her (HBP15). Horace Slughorn had to give him an antidote.
The Order of the Phoenix drank a firewhisky toast to Mad Eye Moody after he was killed during the Battle of the Seven Potters (DH5).
Harry found that kissing Ginny was more intoxicating than firewisky (DH7).
Ron's Uncle Bilius liked to drink a whole bottle of firewhisky and take to the dance floor (DH8)
Rita Skeeter slandered Neville Longbottom, Herbology Professor at Hogwarts and his wife Hannah Abbott, who had applied to be a Matron at Hogwarts, saying that they "both enjoy a little more Ogden's Old Firewhisky than most of us would expect from custodians of our children" (Pm).
"Ogden" may be related to Bob Ogden or Tiberius Ogden.