Alembic is a noun that refers to something that filters or refines.

Coming directly from the French word for a particular kind of cup, alembic can be used either literally to refer to something that filters or refines liquids or it can be used metaphorically to mean anything that serves to filter out something unwanted.

Here’s an example of the latter: My job at the company was to filter out any objects that may have slipped into the printing press. You could think of me as the press’s alembic.