I prefer to use perfectly ripe beans in my potions, so you must only pluck the ripe ones. Under-ripe pods will simply snap; the overripe ones can be a little… messy.
-- Zygmunt Budge
The sopophorous is a magical plant which grows in gloomy marshlands. The roots and the beans are used in potion-making.
The white bean produces a silver juice which has magical properties. If drunk straight, the juice will cause a person to lose their memory. The juice is an ingredient in a number of potions, including the Sleeping Potion (BoP) which is also known as the Draught of Living Death (HBP9). Although some instructions say that the bean must be cut up or chopped, an easier and more effective method is to crush the bean. This produces a large amount of juice which can then be added to the potion.
The plant grows best if Mooncalf dung is used as fertilizer (BoP).
According to the Half-Blood Prince's Potion Book, it's better to crush the sopophorous bean with a silver dagger than to chop it. When Harry follows these instructions, his Draught of the Living Death turns out perfectly, and he wins a bottle of Felix Felicis from Professor Slughorn.
Harry encounters the soporphorous bean during N.E.W.T. level Potions in Sixth Year with Professor Slughorn.
Similar to "soporific," or "sleep inducing" from the Latin "sopor" for "deep sleep"