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I am struggling some with "bitterness".  My thinking is that I am running the nibs through the Juicer too many times trying to get the cocoa liquor yield up. 


Could this be the cause of the bitterness?  If so, how many passes should I run?


Thanks for any feedback.  

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Hi Tom !

We have just tried to roast our DR beans a little bit more. We roasted 100gr of nibs. 5 min at 170°C, and 10 min. at 150° and 10 min at 130°C. I compared the results with my first roasted beans, and what a difference !!! The first beans were very acid, and these ones have lost the acidity and they had chocolate taste. 

I tried also something: I continued to roast some of the beans another 5 min. and I found that it was too much. 

Thank you very much for your advices !

I am still waiting my grinder and I am wondering if 48h will be ok for the chocolate liquor. What do you think ? I will not add additional butter or emulsifiers.

P.S. sorry for my english it's not very good ;-)

Yeah , you wil certainly have a shorter roast profile if you are roasting nibs too
A general rule i use for grinding in a spectra 10 is 2hours grinding for every 500g of nibs into liquor, this makes it fine enough, then add the extra stuff, cocoa butter, sugar, milk powder etc and then you need about 12h for every 1kg of chocolate youare making to get the fineness, but depending on origin you will grind / conch for longer.

Dear Daniel, 

We tested also some DR beans (organic), did two roastings, one starting at 150 C for 8 minutes and than to 130 C for another 17 minutes (25 in total). This restulted in excellent aroma, no bitterness in the nibs. The other roasting was a bit higher temp and longer, but the nibs lost a bit the cocoa and other aroma's. I think you should not go too high with the roasting, otherwise it will turn bitter, also not too long. We didn't make chocolate yet from these beans.  

Best regards

Rodney Nikkels


Amsterdam, Holland

I've been following this thread with interest.


I'm going to weigh in here briefly....


In my opinion, next to fermentation THE most important step in developing the flavour of chocolate is roasting, and THE best way to determine what's going on while roasting is to SMELL what's going on during the roast.  80% of your sense of taste comes from your sense of smell, which is why you can't taste anything when your nose is plugged.


Having said that, ignore the time you are roasting for, and pay attention to what your NOSE has to say about the roast.


During a typical roast, the first smell that you encounter (usually about the 1st 10-20 minutes or so) is a nice "brownie baking" smell.  From there, the beans start to smoke a bit, and a very acidic/vinegary smell develops, which overpowers the "brownie" smell.  At times when we're roasting, the smell in our shop becomes so acidic that my staff's eyes water a bit.  This is the important stage where the acids and some of the tannins are being driven off the beans.


Eventually, as the acids decrease, the smell then again returns to a richer, brownie baking smell, with acidic undertones.   This is usually during the last 1/3 of the roast.


Our roasts (using a convection oven), are usually between 45 and 77 minutes at about 300 degrees F.  Our porcelana is VERY acidic, and requires the longest roast.  In order to prevent burning, we actually reduce the temperature after 50 minutes, to 250 degrees - just enough to continue driving off the acids, but preventing the beans from burning.


With regard to bitterness and astringency, there's not a lot you can do with those characteristics through roasting or conching.  Those two characteristics are of beans that have not been properly fermented.  At least that's been my experience.


So... In conclusion, roast your beans at a lower temperature, and listen to what your nose has to say about what's going on.  Only then can you really nail down the flavour profiles of the beans you are working with.




Thank you Brad.  When I was roasting with the women's groups, we were constantly checking them as they got closer to end.  I noticed that the beans were not quite done, they were still a little moist and slightly rubbery.  Then they were finished, they were more crisp in their bite.  They were also a little dark on the outside before my mentors thought they were done. 

Here is an article that you and others might find interesting, I have cut in the abstract text below but it is the later section of the paper on the ‘Sensory Evaluation of Dark Chocolate’ that is relevant to this discussion and is worth a read see attached file




In this study, commercial Malaysian cocoa beans (SMC1A) were roasted

in a forced airflow-drying oven for 20, 30, 40 and 50 min at 120, 130, 140,

150, 160 and 170C. The products were evaluated for flavor compounds and

sensory evaluation (as dark chocolate). The volatile fraction was isolated

using the combined steam distillation–extraction procedure and was identified

by gas chromatography–mass spectrometry. A quantitative descriptive analysis

was used to evaluate the flavor intensity of the chocolates using a 9-point

rating scale for selected flavor attributes, namely astringency, bitter taste,

sour taste, cocoa and burnt. Panelists were asked to smell and taste the sample

against a standard chocolate. It was found that there were significant differences

in flavor compounds between the different conditions of roasting. The

main flavoring compounds identified composed of aliphatic and alicyclic

groups such as alcohol and ester, and heterocyclic groups such as pyrazine

and aldehyde. A total of 19 volatile major components were identified:

nine pyrazines (2,5-dimethyl-, 2,3-dimethyl-, 2-ethyl-6-methyl-, trimethyl-,

3-ethyl-2,5-dimethyl-, tetramethyl-, 2-ethenyl-6-methyl- and 3,5-dimethyl-2-

methylpyrazine); five aldehydes (5-methyl-2-phenyl-2-hexenal, benzaldehyde,

benzalacetaldehyde and a-ethyliden-benzenacetaldehyde); one methyl ketone

(2-nonanone); two alcohols (linalool and 2-heptanol); and two esters

(4-ethylphenyl acetate and 2-phenylethyl acetate). Based on the flavor profile

of the compounds identified, an optimum production of the major flavoring

compounds such as pyrazine, aldehyde, ketone, alcohol and ester occurred at

160C for 30 min of roasting. Trimethylpyrazine and tetramethylpyrazine compounds

together with 5-methyl-2-phenyl-2-hexanal were found to be good

indicators for the evaluation of the roasting process. However, based on

chocolate evaluation, the best roasting temperature was 150C for 30 min,

which gave the lowest astringency and at the same time gave the lowest bitter

taste and low level of sour and burnt tastes. At 150C roasting temperature, the

desirable cocoa flavor was at its optimum. Correlation coefficients among

certain volatile flavor and sensory characteristics of cocoa beans and dark

chocolate were significant (P 0.05).



Here here!  Science backing up what my nose tells me.  Low and slow.... 



Hi Brad, 

Interesting to read! You mention your porcelana is so acidic, but why is it so acidic, you know? You mentioned that beans are not properly fermented, but from a porcelana you would expect proper fermentation isn't it?



Rodney Nikkels


I roasted today my beans from Venezuela; before roasting the beans were not acid, no bitterness, just a taste of butter.

Firstly I tried the same temperatures and time as for DR beans, just to compare the results. The result for the beans from Venezuela was: the beans developped bitterness and no chocolate aromas; I tried another roasting, at lower temperature, for 15minutes, and the flavours were so different ! beautiful chocolate taste, no acidity, no bitterness. I tasted the nibs with some cane sugar and it was delicious.

Do you think that 15min ( 140°C ) is ok, or it's not too much... ? the result was good, but I see that many of you roast the beans for at least 20minutes. 

Thank you in advance.


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