A mocha pot does not make espresso by modern standards, although it is espresso as it used to be before WWII.
The basic mocha pot rule is to use a grind slightly finer than drip, not as fine as espresso. For the best cup, cut the heat once the water starts boiling, so it's barely oozing out and takes several minutes to finish brewing.
You can use a wider variety of coffee in a mocha pot, both darker and lighter roasted than traditional espresso roasts, although the lightest roasts do better as French press or drip.
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