This invention provides a brewing head unit of a coffee machine for easily inserting or removing the filter (15) and locking the filter and the filter holder (17) into the brewing head of a coffee machine to form a water-and pressure tight connection. The filter and the filter holder can be inserted into the coffee machine of the present invention visually. This invention also provides a cabinet filter holder which can be inserted or placed into the brewing head assembly or unit of a coffee machine by sliding the filter holder into the brewing head unit from the front, to or side or by swinging the filter holder, which is movable attached to the brewing head assembly or unit on a pivot, into the coffee machine. This invention further provides a brewing head assembly or unit, wherein the locking mechanism (13, 20) for placing or orienting the filter holder and securing the filter holder to the brewing head assembly or unit is motor-driven. This invention further provides a cabinet filter design wherein the boiler (19) or heating system is separated from the brewing head assembly or unit.