Does the roasting process lead to weight reduction? If so, what are determining factors? type of coffee? type of roast(dark, medium etc) ?

If you have X lbs of unroasted coffee beans, how much (average) roasted coffee beans you get after roasting?


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.

  • Thanks so much.im planning to start a small coffee roasting business and been studying. – BigM Jan 29 '17 at 2:51
  • 2
    @BigM, I was about to say around 20% for regular roasts. When it's not too light or too dark. Of course roasterbob has much more experience, he already gave a nice answer. – MTSan Jan 29 '17 at 7:27
  • My experience with Ethiopian natural processed beans is right at 15%. That's for a medium roast level. – PJNoes Jan 31 '17 at 23:39
  • Volume also expands with darker roasts expanding the beans more. Almost like puffed rice or something. – Nathan Feb 1 '17 at 19:06
  • @PJNoes, Ethiopian naturals tend to have less shrinkage because they tend to start off with a lower moisture content. So by that fact that have less moisture to lose from the get go no matter what roast level – roasterbob Feb 1 '17 at 23:24

I roast in a bread machine with a heat gun. I roast 567 g per batch (1.25 #). I roast Ethiopian and Kenyan beans. My weight loss is between 12.7% and 16.2% loss. I end the roast at about 210 C (410 F) in about 10 to 12 minutes. If the batch weights in at 500 grams, I delay the cooling until it reaches about 490 grams usually 2 to 3 minutes. Then proceed to stop the roast. Usually the batch will weigh 488 grams which is a city+ for me. My "fireside chat" on Youtube The trout doc has details of process. SH


i roast 2kg Colombian beans at a time (last batch begin 2003g) and end up around 1.6kg (last batch end, chaffed and cooled 1608g) i roast in an oven so need to remove chaff manually (i use a cool hairdryer, fan and a large bowl) so i ended up with a 19.72% reduction (moisture and chaff loss) (1608x100):2003=80.279% so yeah 20% loss for a medium roast, after first crack and before 2nd crack. been cracking beans for over 10 years now. love life love coffee

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.