The present invention relates to a machine for preparing hot beverages, comprising a water tank (1) which can be filled with water (23) and a brewing unit (6) which can be filled with an ingredient (9) such as ground coffee or tea leaves. The water (23) is heated and supplied to the brewing unit (6) for extraction. After the extraction process, the hot beverage (24) flows into a container (8). The machine for preparing hot beverages includes a device (10, 11) for sensing the amount of water and ingredients. The device (10, 11) sends corresponding electric signals to an electronic evaluation device (14). The electronic evaluation device (14) indicates the detected strength of the hot beverage on an indicator instrument (17). The degree of strength may be varied by this arrangement in conformity with a user's taste. Further, only that amount of ingredients required for the desired strength of the beverage is used.