Sometimes the effect of a potion may differ depending on its container... A mixture prepared over heat in a cauldron may imbue with certain properties if consumed. After precipitating in a constricted or perhaps confined environment, the mixture's properties may change. Alchemists who release such a mixtures back into open-air containers have sometimes observed further varying effects..
Be careful to avoid explosions, and watch your eyebrows!
The preparation of potions is a precise science.. The presence or absence of a particular ingredient, or incorrect measurement of a certain material may make the difference between a stinky stew of muck and a marveloux mixture of enchantment.