title_body: What are the 4M's of espresso?
upvoted_answer: 4M is a term mainly used among Italians for espresso. It is a placeholder for four words that start with "M" in Italian that affects espresso preparation. Some information can be found here.
  
  These M's are:
  
  
  Miscela: The coffee-blend; it covers the selection and blending of the beans as well as proper roasting.
  Macinazione: The grinder; proper grinding of the given blend and its usage when its still fresh.
  Macchina: The espresso-machine; usage of the given grounds with a proper espresso-machine.
  Mano: Skill of the barista; usage of all above with skill.