title_body: What ensures a better cup of coffee, a spotless grinder or freshly ground coffee?
upvoted_answer: Always grind fresh.
  
  Considering that the roaster you buy the 250 gr pre-ground coffee also uses some grinder and at most wipes its burrs daily, I would go for the first option. The residual coffee could be easily removed by
  
  
  wiping reachable parts first
  then grinding a small amount of fresh coffee
  
  
  before actually grinding for your cup.