Bitterness

Daniel Mollsen
@daniel-mollsen
12/13/11 01:06:53PM
8 posts

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, howmany passes should I run?

Thanks for any feedback.


updated by @daniel-mollsen: 04/13/15 09:53:35AM
Maria6
@maria6
12/13/11 02:05:24PM
35 posts

What type of beans do you use ? How do you roast the beans ?

After grinding, and conching, does your chocolate rest for some days or weeks ? This time is necessary to eliminate bitterness and acidity.

Daniel Mollsen
@daniel-mollsen
12/13/11 02:11:20PM
8 posts

Maria- Thank you! I've been experimenting with a number of different types of beans. I have a convection oven for roasting. I have not been letting it rest. How longdo you recommend after conching? What is the best"resting"/storage method? Do you let it rest and THEN temper it? Agasin, thank you.

Maria6
@maria6
12/13/11 02:23:00PM
35 posts

Hi again Daniel,

I am just starting my business, I don' t have a lot of practical experience. I know that roasting is very important and if the temperature is high the beans become very bitter; what is the temperature and the time you chose ?

You write that you use different type of beans, and do you find that all are bitter or just some of them ?

I use also a convection oven, I roast the beans at 130C for 20minutes, and I think it's ok.

I learnt that after conching resting is necessary to remove bitterness, I think 2-3 weeks is good, at room temperature. And only then you can temper it.

Daniel Mollsen
@daniel-mollsen
12/13/11 02:31:35PM
8 posts

WOW. Thank you. I am literally just starting and your insight is quite helpful. In our brief exchange you have helped me realize a couple of my mistakes. 1)I am roasting at too high a temp (350 F until I hear the beans crack) and 2) not allowing the chocolate to rest.

How many times do you pass the roasted nibs/liquor through the processor? Is there such a thing as too much?

I wish you the best of luck in your business!

Tom
@tom
12/13/11 02:37:14PM
205 posts
I agre with Maria, aging will allow the bitterness to 'settle', I age mine after tempering but I don't think it really matters. Some origins get very bitter if you roast them too long, I have found this pronounced in beans from peru and the philippines and to some extent with vanuatu. Roasting shorter and cooler is the solution here. As a general rule astringency deacreases with roasting and bitterness increases so you just got to find the sweet spot. One more thing you can do if it is all to bitter is to make a dark milk chocolate, even just a little milk powder in the formulation can reduce bitterness significantly.
Maria6
@maria6
12/13/11 02:48:00PM
35 posts

Hi Tom ! Thank you for this information and the advice for dark milk chocolate.

I use Domenican Republic cocoa beans, type Hispaniola, and I don't roast them more than 20 minutes. Did you use this type of beans ?

Daniel: thanks for your answer ! I don't use a Juicer, I bought a grinder from CocoaT, I didn't use it yet. But I don't think that if you pass the roasted nibs through the juicer, they become bitter. I think that you have to try to roast the beans at lower temperatures, between 260F - 300F.

Daniel Mollsen
@daniel-mollsen
12/13/11 02:52:24PM
8 posts

Tom and Maria, thank you is all I can say.Roasting and resting will be focal points for the next go!

Tom
@tom
12/13/11 05:39:57PM
205 posts

No worries on the help.

Maria, I have used this bean from Chocolate Alchemy, many years ago, I found it was quite astringent bean, in fact so astringent that it curdled milk when I used it to make hot chocolate. It is definitly one that needs 'resting'. I think from memory it was a cooler longer roast I used on this bean. I just looked it up in my notes and it was 800g of beans in one tray for5 min (170degreesC), 27 min (150degreesC) and then turn oven (kitchen convection)off and leave door open for 10 min then take out of oven and cool (I stir the beans every 5 mins or so during the roasting). I find this last resting in the oven with it off and the door open really developes some good chocolatey notes in the beans and reduces some of that bitterness(some beans that is, not all,I tend to use it on this type of bean and in Vanuatu as it is quite tannic too).

Dark milk chocolate is a great chocolate, if you are setting up a business. For the Australian taste, this is the type of chocolate I would be selling, it is by far and away what people here that taste my chocolate like the best.

Thomas Forbes
@thomas-forbes
12/13/11 06:19:05PM
102 posts

I recently bought a small cocao town melanger and have made a dozen or so micro batches in the last month or so. Using mostly Hispanola from the DR and brought back some Sanchez and a couple of pounds "80%" Hispanola. These women cooperatives roasted, milled, winnowed and did a gritty grind and make them into 4oz balls. I also had the chance to translate this summer and see how beans are roasted in a small factory using a continuous method.

Temperatures were much lower. They set the factory roaster at around 170 C to have 115-120 C on the beans. Around 250 F. One women's group uses a pizza type oven and was going toward 350F and burning them. They were putting them in a cold oven and letting it sit for a couple of hours without attending to them. I did a roast with them and the temperatures ranged from 250F - 320F and I had it as low as it would go. It took 45 minutes in a hot oven. The other women's group is roasting in a big open cast iron pot with wood. I measured temperatures around 300F as it reached it's peak. It was about an hour as the pot warmed up and 40-45 for the remaining batches.

I am running out of paste and will have to start buying beans and I appreciate this discussion.

I did one batch of milk chocolate and wondered what percentage of milk powder do you use?

I haven't been aging my chocolate either. Too eager to start using it.

Tom
@tom
12/13/11 06:44:19PM
205 posts

10-15% milk powder is a good start for a dark milk choc. I findaround 10%for DR type beans and more for fruity beans like Madagascar.

Maria6
@maria6
12/14/11 02:38:21AM
35 posts

Tom, Thomas, thank you very much to share your experience with these beans. It's so usefull for me ! So, I think, that I have to roast these beans more than 20min if the temperature is 130C. I will try later to roast the beans at higher temperatures and for 40 minutes at least, and I will compare the results.

The other type of beans I wil use is Rio Caribe, Venezuela. Have you ever worked with this type of beans ?

Thank you in advance !

Tom
@tom
12/14/11 05:49:18AM
205 posts
I agree that your roast sounds a little light for the DR, however, I must tell you that in my roasting pan the beans sit about two to three deep, hence my stirring. If you have them one bean deep they heat and roast a bit quicker.I have not worked with Rio Caribe yet, but it will undoubtedly be less tannic. I would probably do something like 5 min at 170 then 20 min at 150 with no resting in the oven, I would be tasting the beans all the time to find the best end point though. I taste the beans regularly to assess how long, a good way, well the way I do it is to take out two beans, one on the big side and one on the smaller side, shell them and pop them both in my mouth with about a quarter of a teaspoon of sugar then chew it around for a bit without swallowing. With practice and knowledge of the flavours in your finished chocolate you can get a very good read on how the roast is progressing with this method. It is also really good for detecting two things, astringency and bitterness. The key is to keep chewing to get the paste nice and fine only then can you really start to 'taste' where your roast is at in terms of astringency and bitterness. Roasting is the best bit, I think, a new bean origin, a new challenge, and the house smells so damn good!
Maria6
@maria6
12/14/11 07:05:20AM
35 posts

Hi Tom !

We have just tried to roast our DR beans a little bit more. We roasted 100gr of nibs. 5 min at 170C, and 10 min. at 150 and 10 min at 130C. 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 ;-)

Rodney Nikkels
@rodney-nikkels
12/14/11 07:49:04AM
24 posts

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

Chocolatemakers,

Amsterdam, Holland

Tom
@tom
12/14/11 02:49:10PM
205 posts
Yeah , you wil certainly have a shorter roast profile if you are roasting nibs too
Tom
@tom
12/14/11 02:55:17PM
205 posts
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.
Brad Churchill
@brad-churchill
12/14/11 03:06:59PM
527 posts

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 tanninsare 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.

Cheers.

Brad

Thomas Forbes
@thomas-forbes
12/14/11 05:19:35PM
102 posts

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.

Tom
@tom
12/14/11 09:50:36PM
205 posts

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

INFLUENCE OF ROASTING CONDITIONS ON VOLATILE FLAVOR OF ROASTED MALAYSIAN COCOA BEAN Journal of Food Processing and Preservation 30, 2006, p280

Abstract:

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 distillationextraction procedure and was identified

by gas chromatographymass 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).

Tom
@tom
12/14/11 10:01:49PM
205 posts

Here

Brad Churchill
@brad-churchill
12/15/11 01:23:32AM
527 posts

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

cheers

Brad

Rodney Nikkels
@rodney-nikkels
12/18/11 01:30:09PM
24 posts

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?

Best

Rodney Nikkels

Amsterdam

Maria6
@maria6
12/20/11 02:48:33PM
35 posts

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 ( 140C ) 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.

Clay Gordon
@clay
12/20/11 06:11:53PM
1,680 posts

Maria -

It's not so much the difference in gross origin (Venezuela vs the DR), it's differences in the variety (genetics) of the bean modified by various aspects of terroir, and I include post-harvest processing techniques as a part of terroir.

If 15min at 140C is what works for you - then that's what works for you. Your beans, your roasting technique.

The exact times and temps for others does not really matter.

EXCEPT ... in the absence of testing, 15min at 140C does not guarantee that pathogens (e.g., salmonella) on the outside of the beans are killed to an "acceptable" level. So, you probably want to do some lab analysis on a regular basis (e.g., each new shipment of beans at least) to make sure that everything is safe.




--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
clay - http://www.thechocolatelife.com/clay/
Maria6
@maria6
12/21/11 02:34:18AM
35 posts

Hi Clay,

thank you for your help. Actually I buy the beans from a broker and he gives me all the sanitary certificates. Do you think that there is a risk ?

A read that salmonella and all the possible bacterias are killed if the temperature is 70C or more. May be for cocoa beans is different ?

Sebastian
@sebastian
12/21/11 08:39:03PM
754 posts

Is the broker telling you that the whole beans you are receiving are, in effect, sterilized? If so, I would absolutely, unequivocally, insist that they demonstrate proof of that if you do not have a kill step of your own, and I'd challenge their results by having them validated yourself with a 3rd party. A piece of paper saying they're clean is meaningless.

Mark Allan
@mark-allan
06/27/14 03:23:12PM
47 posts

I realize this is a very old thread, but I am just starting and coming across the same challenge. Until today I had no idea how much resting could help with the bitterness of the chocolate. I have battling the bitters for months. Today I reached into a box of chocolates and grabbed a piece of milk chocolate I had made over a week ago. Last week the bar had a bitter aftertaste. Today, I noticed none.

Normally after I mold any candy that I make, I put it into plastic bags.

My question on the resting, under what conditions should the chocolate "rest"? I typically keep my un-molded chocolate in plastic bags, but should it breathe? Have some airflow? Or should it at least be in a large container that is not airtight?

Thanks,

Mark C.

Sebastian
@sebastian
06/27/14 04:46:51PM
754 posts

I'm a huge advocate of letting your chocolate age 3-4 weeks before finalizing a recipe; however in my experience bitterness is not one of the elements that changes significantly over age. The components that result in bitter attributes are not volatile.

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