# Bean mass too low after roasting



## Nate D (Nov 18, 2020)

Hi all,

I have just purchased a new Kaldi Mini roaster to learn how to roast coffee.

I started with 200g green beans (Guatamala Washed), and roasted it through 11 mins whilst taking down the temperatures at each minute, recorded charge temp, first crack, etc. I have done this about three times and still the same result.

The main issue is, that somehow I have managed to almost halve the mass of the beans (200g->120g), and cannot seem to understand why? I have read that usually the expected loss of mass due to water is 12-25 percent, and for some reason my weight loss has been approx 40-50 percent... I did not burn the beans (or at least I don't think so), and the roasts were on the medium to dark side.

I am completely new to this, but really want to learn how to roast a good batch. If there is a glaringly obvious mistake, I will be very happy to learn it.

PS. first post, hi guys!


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## Rob1 (Apr 9, 2015)

It's possible you're roasting beans that haven't been properly dried and so have more moisture to lose.


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## alanmason (Sep 3, 2020)

I don't think that the loss of mass is a problem, if the beans taste good after a few days of degassing then everything is ok. Perhaps the beans have a high moisture content to start with. You could try some different beans and see how they compare or roast another batch a bit lighter and compare these results too. At the end of the day a good tasting coffee is the result that matters, if you have that then it doesn't really matter how you got there.


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## Rob1 (Apr 9, 2015)

alanmason said:


> I don't think that the loss of mass is a problem, if the beans taste good after a few days of degassing then everything is ok. Perhaps the beans have a high moisture content to start with. You could try some different beans and see how they compare or roast another batch a bit lighter and compare these results too. At the end of the day a good tasting coffee is the result that matters, if you have that then it doesn't really matter how you got there.


 High moisture content can cause mould to develop on the green coffee so it is a problem. It will also affect the taste and roast significantly (not just if it goes mouldy). And of course aside from all that when you buy 10kg of green coffee you expect to get at least 8kg roasted from it, not 5-6 so there's the cost to consider.


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## Nate D (Nov 18, 2020)

thanks for all the replies. interesting, i will try a different type of green bean and will report back. i did have a suspicion that it could have had something to do with the moisture content as otherwise that much loss of mass through chemical breakdown would imply charcoal.


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## Rob1 (Apr 9, 2015)

Where did you buy them and how much were they?


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## DavecUK (Aug 6, 2013)

I'm suspecting measurement error....


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## Rob1 (Apr 9, 2015)

DavecUK said:


> I'm suspecting measurement error....


 Well yes, I was thinking that but just decided to go with benefit of the doubt....I'll never learn.


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## DavecUK (Aug 6, 2013)

I think if the beans had that much moisture...they would have come from a can! 😉


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## Stevebee (Jul 21, 2015)

I agree measurement error. Unless there's a hole at the back of the roaster 😀Check the floor for a pile of roasted beans!


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## Rob1 (Apr 9, 2015)

Guatemala 'washed'. You didn't wash them yourself?....

Ok no more jokes.


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