In Harry Potter and the Philosopher's Stone, Harry, Ron, and Hermione fight their way through several chambers only for Harry to find Professor Quirrell with Voldemort's face sticking out of the back of his head. However, in the last room there was a logic puzzle involving potions. The potion that let Harry pass forward was a small container only able to hold a small swallow of potion.

If this is true, and it really could only hold that little amount, how did Quirrell get to the next room without apparating?

  • 1
    Maybe Quirrel with the Dark Lord's help could use some magic to pass the magical flames without bothering with Snape's potions.
    – b_jonas
    Apr 26, 2012 at 14:49
  • 3
    This reminds me to Tarquin's statement from the Order of the Stick giantitp.com/comics/oots0821.html : "In any race for hidden treasure, it is always the protagonists who sweat and bleed and die to overcome the many challenges inherent in finding it – only for the antagonists to sieze it from them at the last minute." So Quirrel got had a free pass on the obstacles, he got there because of the narrative rules.
    – b_jonas
    Sep 11, 2014 at 21:13

2 Answers 2


There was enough potion for one when Harry and Hermione got there, so maybe there was enough for two sips when Quirrell faced the same puzzle, and he must have drank half of the contents of the potion.

On the other hand, Snape could have put a charm on the potions so they would refill for different people (not for the same person, so if one fails and go back, they can't try again).

  • 2
    I don't think the first part is the right answer. If it was, harry and hermione could have inferred the right potion just by looking for a bottle which has already been used.
    – Philipp
    May 28, 2017 at 10:10
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    Your last though doesn't make sense. If someone fails and goes back, why would they try the same potion again? How would that help them? The refill charm makes sense (not having to manually refill everything), but I see no inherent "cheat" attached to having the bottles refill automatically.
    – Flater
    Sep 20, 2017 at 15:32
  • @PhilippFlenker He could have poured some other potions on the ground, or into the fires. And anyway, does it say that the bottles are clear? May 30, 2018 at 15:57

I believe the bottle was being refilled every time.

The bottle containing the correct potion is the smallest of the bottles in line:

“Got it,” she said. “The smallest bottle will get us through the black fire – towards the Stone.”

Harry looked at the tiny bottle.

“There’s only enough there for one of us,” he said. “That’s hardly one swallow.”

Philosopher’s Stone, chapter 16 (Through the Trapdoor)

I believe this is a deliberate design feature: it means only one person can enter the final chamber at a time. If it was a group of people moving through the chambers, this would slow them down.1 Two of the other traps – the flying keys and the chessboard – reset after Quirrell went through, so it’s reasonable to suppose that it could happen here as well.

Why would you want it to reset? So that the first person through can’t stop everybody else.

If Quirrell just poured out the remaining contents of the bottle (or drank it in one go), then Harry is scuppered. I’d expect Quirrell to do this, so the fact that there’s any potion left at all seems like a pretty strong hint that these potions are not quite what they seem.

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