A method of separating trub from hot wort, in which unpurified hot wort is supplied to a settling device and after the settling process purified wort is withdrawn at a level above the bottom of the settling device, and trub is withdrawn at a level at or near the bottom of the settling device. According to the invention, a natural circulation is created in the settling device by withdrawing heat from one part of the surface of the wort liquid and screening off the other part of the surface. A column of liquid topped by said one part is kept separate from a column of liquid topped by the other part throughout its entire height, except for a narrow upper edge region and a bottom edge region. The method can be carried out by means of a separator comprising a container with top (6), bottom (5) and sidewalls (1, 2) and filling and drain means in which a substantially vertically extending wall member (7) is disposed in the container at least throughout the major part of the height thereof to separate a first space within said container from a second space within said container, the container being partially closed by the top wall, which extends over said one space and leaves the top of the other space free, there being openings between said top wall and said wall member, through which the spaces are in communication with each other.