The biggest problem people find when using Moka pots is not knowing when the coffee has finished brewing, often waiting until they hear the spluttering of coffee from the percolating column. By this time the heating process is well under way will continue until the coffee gets over extracted and a brown liquid is boiling away in the top chamber. That, or they are constantly lifting the lid to ‘see’ when the coffee is ready and burn their fingers in the process.
So the simple, but brilliant, innovation was to add a window to the Moka pot lid. The user can now easily see when the coffee begins to pour out of the percolating column, can remove the pot from the heat and leave it to finish the brewing process without danger of killing the coffee.