The use is somewhat complicated and requires time taken in hand. The position of the capsule, the compacting and fineness of the grind affect the result. After about ten cafes I'm getting the hang of it and the result is very correct. Do not hesitate to use the proper ground coffee when preparing the cup. On a machine Krups Essenza Black, I never blocked the capsule in the duct. The price of coffee is divided by 4 and if it comes from a roaster, will have nothing to envy to those of the brand ... and less pollution, perhaps ...