Potions Master

A Potions Master is the title given to the professor who teaches Potions at Hogwarts School of Witchcraft and Wizardry. The position is highly influential within the school, responsible not only for educating students in the “subtle science and exact art” of potion-making but also for managing the school's apothecary and, traditionally, serving as the Head of House for Slytherin House. The two known Potions Masters during the events of the series, Severus Snape and Horace Slughorn, both played pivotal roles in the Second Wizarding War.

The Potions Master has a range of critical responsibilities that extend beyond the classroom.

• Instruction: The primary duty is teaching Potions to students from first year through seventh year. This includes creating lesson plans, supervising practical brewing sessions, and grading theoretical essays and exams for both O.W.L.s and N.E.W.T.s.
• Apothecary Management: The Potions Master is in charge of maintaining and stocking the school's supply of potion ingredients. This involves ordering, storing, and securing a vast array of common and rare components, some of which are highly dangerous. The ingredients are stored in the Potions classroom and the Master's private stores.
• Institutional Brewing: The Master is often called upon to brew complex potions for the school's needs. Most notably, they supply the Hospital Wing with remedies. For example, Severus Snape was tasked with brewing the Wolfsbane Potion for Remus Lupin and was responsible for brewing the Mandrake Restorative Draught to cure those petrified by the Basilisk.
• Head of House: Both known Potions Masters also served as Head of Slytherin House. This role includes responsibilities such as student discipline, attending Heads of House meetings with the Headmaster, and acting as a guardian and advocate for the students in their House.

The Potions classroom is located in the dungeons of Hogwarts Castle, contributing to its characteristically cold and gloomy atmosphere, even in warm weather. The room is large enough to accommodate multiple classes and is filled with worktables and cauldrons. The walls are lined with shelves holding glass jars containing slimy, pickled creatures, herbs, and powdered ingredients in a kaleidoscope of colors. The preserved specimens serve as both teaching aids and a ready supply of ingredients. An office is attached to the classroom, which serves as the Potions Master's personal workspace. Under Severus Snape, it was a dim, unnerving room where he would intimidate students. Under Horace Slughorn, it was a more comfortable space used to host his exclusive Slug Club meetings.

• Severus Snape (c. 1981 – 1996): Snape held the position from shortly after the end of the First Wizarding War until he finally achieved his long-held ambition of teaching Defence Against the Dark Arts in 1996. He was a deeply talented and knowledgeable Potions Master, though his teaching style was marked by strictness, terror, and a pronounced bias against any student not in Slytherin House, especially Harry Potter. He was the author of the advanced potions textbook used by Harry, which belonged to the Half-Blood Prince.
• Horace Slughorn (Dates of first tenure unknown – 1981; 1996 – 1997): Slughorn was a long-serving Potions Master who retired in 1981, being replaced by his former student, Severus Snape. He was coaxed out of retirement by Albus Dumbledore to resume his old post in 1996. In contrast to Snape, Slughorn's teaching style was jovial and encouraging, though he was known for his blatant favouritism, collecting talented or well-connected students for his Slug Club.

The role of Potions Master is central to the narrative of the Harry Potter series, primarily through the two characters who hold the post. Severus Snape's position allowed him to be a constant antagonist to Harry Potter while secretly working to protect him on Albus Dumbledore's orders. His expertise in Potions was a recurring demonstration of his powerful magical ability. Horace Slughorn's return to the post was engineered by Dumbledore for a single, crucial purpose: for Harry to retrieve Slughorn's untampered memory, which revealed that Tom Riddle had inquired about Horcruxes. This information was the key to defeating Lord Voldemort. Furthermore, the subject of Potions itself is a vital plot device, providing the heroes with essential tools like the Polyjuice Potion, Veritaserum, and Felix Felicis.

• On the Pottermore website, J.K. Rowling explained that because Potions-making is associated with dark secrets and has a “murky, ambiguous” nature, it was fitting that a complex and morally ambiguous character like Severus Snape would be its master. (Pottermore)
• In the film adaptations, the Potions classroom set is depicted as a vast, stone-walled laboratory filled with thousands of jars, intricate glassware, and self-stirring cauldrons, emphasizing the scientific and mysterious nature of the subject. (film)