title_body: Taste of coffee that has not rested long enough
upvoted_answer: To me, the more likely result of insufficient "rest time" is a lack of flavor. It tastes like coffee, but without enough depth of flavor. In that case, I will simply let it rest for two days, then try the coffee again. Usually there is a noticeable improvement.
  
  In some cases, the flavor will not improve with more rest. That means that I did not roast the bean far enough. So I make a note to roast a bit longer (10 to 15 seconds) next time.