Decantation is a process for the separation of mixtures, carefully pouring a solution from a container, leaving the precipitate (seiments) in the bottom of the container. Usually a small amount of solution must be left in the container, and care must be taken to prevent a small amount of precipitate from flowing with the solution out of the container. It's generally used to separate a liquid from an insoluble solid, e.g. in red wine, where the wine is decanted from the potassium bitartrate crystals. Another example is when separating the oil from water after getting them as a mixed liquid out of olives in order to extract olive oil.