I have been loving Miscela d'Oro espresso beans (Gran Crema or Gusto Classico). I haven't made a liqueur with this brand, but it does deliver an espresso that is unrivaled (pulled from a La San Marco machine) -- great crema, round flavor, just the right amount of acidity, etc. You can buy the beans on Amazon for a good price. Here is a link to the corporate website: http://www.misceladoro.com