title_body: How much weight reduction occurs after roasting coffee beans?
upvoted_answer: The roasting process leads to water loss in all types of beans. Most beans start off at about 10-12% moisture and end up around 3%.
  My experience gives about 15% weight loss (shrinkage) for light roasts and around 20% on dark roast profiles.
  
  Example of a dark roast weight loss in my roasterie would be: 
  Starting weight: 240#
  Roasted weight: 195#
  Shrinkage = 195/240 = 81% of start weight so 19% loss.
  
  I can't seem to find any online documentation of this. Just daily experience of being a professional roaster.