title_body: Does coffee taste different when it is ground at home?
upvoted_answer: I bypass the first question.
  
  Yes, ground size considerably affects the taste of the final cup. In general, there's a common rule of five component for a good cup of coffee. Each component must require its precedent.
  
  
  Good beans
  Good roasting
  Homogenously/correct-sized grinding
  Correct equipment
  Skilled cook
  
  
  (Italians mostly merge first two articles and name it as 4M for espresso.)
  
  As stated above, the grounds must be all at the same size. Moreover they must be the correct size. The finest for Turkish, a bit less fine for espresso, boulders are good for French press, etc.