to blow air in the reception chamber 2 during the extraction period with the result that because of the generated overpressure air will be pressed upwards through the filter paper web 3 and through the mixture of water and coffee or tea powder as a result thereof the mixture will be strongly agitated which is beneficial to the extraction in many cases the pump unit 11 can be embodied as a double acting pump in such a case it will be sufficient for the unit 13 to deliver a suitable control signal at least during a part of the extraction period to the pump unit 11 so that the pump unit 11 will start functioning as a blowing device blowing air through the conduit 12 into the reception chamber 2 at the end of the extraction period and respectively at the beginning of the suction period again the unit 13 supplies a suitable signal to the pump unit 11 such that the moving parts of this pump unit 11 will start rotating in the reverse direction causing the pump to suction air through conduit 12 from the reception chamber 2 to achieve the effect described above if for one reason or another an irreversible pump has to be used which is only able to function in one manner then even in such a case this pump can be used for blowing air as is indicated in the example illustrated in fig2 the differences between the embodiments illustrated in fig1 and 2 are found in the region around the pump unit 11 in the embodiment of fig2 the pump unit 11 is with its suction port through the suction channel 12 connected to the reception chamber 2 whereby the channel 12 comprises a three way valve.