Elements leading to this idea: Coffee beans require grinding, roasting(or possibly steaming), filtering and then having hot water passed through the resulting granules.
Of course, the best coffee is made with off-boiled water so we'd require some cooling if we were to boil the water straight off from say, a steam engine with a grinding mechanism for the beans.
The exhaust steam could be passed in to a chamber to wet roast the beans, after which the beans are passed to the grinder and then again, in to the filter at which point the steam from the 1st chamber can be evactuated through the coffee after cooling. If there is no reciptical provided for the coffe, it can be stored in a warm container to keep it at an acceptable temperature, if a receptical is provided, the coffee could be evacuated for you drinking pleasure as soon as is ready, a whistle should be present to alert you to it's state of readyness.
So long as the machine is topped up with beans and water, you will have freshly made coffee for as long as you have a receptical.-- SPTwizz, Oct 09 2009 Babbage Coffee Machine Babbage_20Coffee_20MachineThe surrounding idea is much more detailed than the one in this link. [jutta, Oct 09 2009] Hm. I remember the water coming off a steam engine as smelling kind of oily - it's a romantic idea, but you wouldn't want to drink that. Doesn't mean that you can't use the same heating element for your espresso and the moving parts - just keep the water in separate cycles.-- jutta, Oct 09 2009 sp. "receptacle"
yaay, coffee!-- CaptainClapper, Oct 09 2009 i don't get how this is perpetual, where do the grounds go? Also how do you meter the grounds into the chambers? What prevents the user from tapping off a toddy of coffee and leaving 4oz of slightly extracted grounds. Finally I question the notion that, without grinding very finely, a good cup can be made without some time (grounds in water) for the brew to extract. The idea is neat but this is 100 % generalities 0% an actual device.-- WcW, Oct 09 2009 //water coming off a steam engine as smelling kind of oily// coffee-bean oil ?-- FlyingToaster, Oct 09 2009 random, halfbakery