When they reached the Alchemy lab, the Witches picked their spots and began setting up equipment for the potion. According to the information that had been left up on the board, they didn't need much, only a cauldron, a burner and a few beakers.
The small, cast iron pots looked out of place in the modern scientific surroundings, but according to the notes left over from Professor Ashcroft teaching students about this potion, the thick walls of the pressure vessel helped with even heating. The bubbling and boiling, very witchy part of the potion-making was only for certain recipes which needed to be physically stirred in a ritual pattern.
Wolfe examined the small cauldrons more closely, noticing that they did, in fact, have lids that could be screwed on with an adjustable vent so it could release pressure at a preset level.