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Post by brelto85 on Jan 7, 2021 6:57:40 GMT -5
hello everyone,
I have been having some problems with refining for the past month.
With the same batch of cocoa beans, after roasting and cooling, the beans were quick to refine. Even in pre-refining the butter inside the beans melted quickly and the refining was optimal.
Recently, during the pre-refining process, it thickens quickly and does not allow the butter to melt, and in the refining process there is a higher viscosity.
could it be caused by the humidity of the beans and the environment where they are stored (we are around 16 C° and 40% humidity) or by the temperature of the environment where I proceed with the refining (always around 16/17 C°)?
thank you very much
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Post by Ben on Jan 7, 2021 9:04:12 GMT -5
16C and 40% humidity shouldn't cause any problems. Can you give information on your roasting, pre-refining, and refining processes?
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Post by brelto85 on Jan 7, 2021 9:16:26 GMT -5
Thanks Bena! I roast the cocoa in a professional convection oven with these temperatures (work in a kitchen laboratory)
100C - 10 min 120C - 15min 125C - 25 min
After letting them cool for a few hours I remove the skin and start grinding them in a professional food processor in order to start a first refining (not to stress the melanger too much by throwing the grain directly into it). Already at this stage I see that it is very difficult to dissolve. everything thickens on the walls
Then after a bit of effort it manages to heat up a bit and slowly I throw in the melanger
The strange thing is that with the same beans (same bag), two months ago this behavior did not happen to me. It seems to me that it was a problem that occurred progressively
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Post by Ben on Jan 7, 2021 11:05:22 GMT -5
Have you been using this same roasting technique the whole time? Do you take the bean temperature at various points during the roast? It seems kind of cool for roasting cacao, which could lead to moisture remaining in the beans, which could then lead to thickness.
A couple things to possibly look into/try:
Has the food processor blade dulled over time?
Have you tried rewarming the nibs before pre-refining?
Do you get any steam during pre-refining?
On a side note, why do you progressively heat the oven hotter during your roast? I've generally seen the opposite.
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Post by brelto85 on Jan 7, 2021 11:17:18 GMT -5
Has you been using this same roasting technique the whole time? Do you take the bean temperature at various points during the roast? It seems kind of cool for roasting cacao, which could lead to moisture remaining in the beans, which could then lead to thickness.
--yes I have always used the same temperatures and we have been in production for about a year and I have never had this problem so frequent. I've already tried to increase but above 130C with this oven it starts to feel like the over-roasting
A couple things to possibly look into/try:
Has the food processor blade dulled over time? --This could be an element to verify
Have you tried rewarming the nibs before pre-refining? --No
Do you get any steam during pre-refining? --Sometimes yes
On a side note, why do you progressively heat the oven hotter during your roast? I've generally seen the opposite. --I've always used that "profile". do you think it's better to do it the other way around? what changes in terms of internal roasting in the beans?
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Post by Ben on Jan 8, 2021 9:02:19 GMT -5
Steam during pre-refining could condense back into the chocolate and thicken it. This could possibly be part of the problem. It may mean that your beans are under-roasted and that there's too much moisture remaining in them.
You didn't say whether you are monitoring your bean temperature. This is far more important than the temperature of the oven.
The beans can take a hotter temperature at the beginning during the drying phase, which could let you reduce the length of your roast. Once you reach the end of the drying phase (bean temp of 212F/100C), how the bean progresses through the development and finishing phases has a great impact on the flavor. A lot of times that involves slowing down the rate of rise to bring out different flavors. Higher oven temperatures at this point could result in the bean not being fully roasted to the center, I'd guess. That being said, your roast time is very long, so it is probably roasted consistently enough, but as your oven temperatures are pretty low it may mean that it is under-roasted in general. To really know anything, though, you need to know your bean temperature.
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Post by brelto85 on Jan 9, 2021 9:57:15 GMT -5
Steam during pre-refining could condense back into the chocolate and thicken it. This could possibly be part of the problem. It may mean that your beans are under-roasted and that there's too much moisture remaining in them. You didn't say whether you are monitoring your bean temperature. This is far more important than the temperature of the oven. The beans can take a hotter temperature at the beginning during the drying phase, which could let you reduce the length of your roast. Once you reach the end of the drying phase (bean temp of 212F/100C), how the bean progresses through the development and finishing phases has a great impact on the flavor. A lot of times that involves slowing down the rate of rise to bring out different flavors. Higher oven temperatures at this point could result in the bean not being fully roasted to the center, I'd guess. That being said, your roast time is very long, so it is probably roasted consistently enough, but as your oven temperatures are pretty low it may mean that it is under-roasted in general. To really know anything, though, you need to know your bean temperature. thanks a lot for the information Ben I'll try checking the temperature inside the beans and changing strategy starting with higher temperatures going down for a shorter period of time the fact that with the same roasting temperatures a few months ago I didn't have these problems could be caused by the fact that having more heat in the lab, the beans cooled more slowly continuing a sort of internal roasting?
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Post by Ben on Jan 9, 2021 18:39:32 GMT -5
Slower cooling would result it more moisture loss, so if anything, it should help.
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Post by brelto85 on Jan 19, 2021 4:41:41 GMT -5
Good morning Ben,
Following your advice I did some testing and roasting with the following "profile" and now the beans seem crisper and removed more moisture (I weighed them)
150-2 (loading beans) 130-10 125-10 120-10
I also heated up the pre-cooler and now it is doing better in melting
The internal temperature of the beans at the time of extraction from the oven is about 85/90 C
What I never understood however is the following question: In theoretical terms, also by studying a lot on your site, what is the difference between roasting cocoa beans starting from high temperatures and starting from low temperatures?
in particular what is the difference between these profiles?
150-2 130-10 125-10 120-10
or
120-10 125-10 130-10 150-2
Chemically what changes in the beans? They receive the same temperature for the same time
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Post by Ben on Jan 19, 2021 9:28:16 GMT -5
Note that Chocolate Alchemy isn't my site. It's John Nanci's (the Alchemist). I just help out with moderation on the forums (mostly just deleting spam and moving posts into more appropriate forums). As John mentions in his Ask the Alchemist series on roasting profiles (starting at ATA200 or so), how quickly a bean moves through the drying phase (room temp to 212F) doesn't have much affect on the flavor. The most important thing is what is the rate of rise as it enters the development phase. Other than that, it just makes sense to move through the drying phase as quickly as possible without scorching the beans. Once the beans have passed 212F and enter the development phase, how they progress through that phase and the finishing phase make a big difference in the flavor. Moving quickly through them may work best for some beans, while others need to move slowly through them. It's helpful to think of the roasting curve as plotted on a graph. Some beans want a gentle curve with a long finish and others want a steeper curve that drives towards the end of roast temp (EOR). When you say 'internal temperature' of the beans, do you mean the temperature in the mass of the beans or the actual inside of the beans? If the latter, how are you measuring that? Generally, only the external temperature is measured. You can do this most easily in an oven using an infrared thermometer. 90C (194F) is way too cool for an EOR. Generally cacao is roasted to an EOR of somewhere between 220F (104C) and 270F (132C) or so. It sounds like you are taking a long time to under-roast your cacao. Oven temperatures don't really matter and aren't really a roast profile. What matters is the temperature of the beans, and the oven should be controlled to generate the bean roast profile that you want.
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Post by brelto85 on Jan 19, 2021 10:00:41 GMT -5
Note that Chocolate Alchemy isn't my site. It's John Nanci's (the Alchemist). I just help out with moderation on the forums (mostly just deleting spam and moving posts into more appropriate forums). As John mentions in his Ask the Alchemist series on roasting profiles (starting at ATA200 or so), how quickly a bean moves through the drying phase (room temp to 212F) doesn't have much affect on the flavor. The most important thing is what is the rate of rise as it enters the development phase. Other than that, it just makes sense to move through the drying phase as quickly as possible without scorching the beans. Once the beans have passed 212F and enter the development phase, how they progress through that phase and the finishing phase make a big difference in the flavor. Moving quickly through them may work best for some beans, while others need to move slowly through them. It's helpful to think of the roasting curve as plotted on a graph. Some beans want a gentle curve with a long finish and others want a steeper curve that drives towards the end of roast temp (EOR). When you say 'internal temperature' of the beans, do you mean the temperature in the mass of the beans or the actual inside of the beans? If the latter, how are you measuring that? Generally, only the external temperature is measured. You can do this most easily in an oven using an infrared thermometer. 90C (194F) is way too cool for an EOR. Generally cacao is roasted to an EOR of somewhere between 220F (104C) and 270F (132C) or so. It sounds like you are taking a long time to under-roast your cacao. Oven temperatures don't really matter and aren't really a roast profile. What matters is the temperature of the beans, and the oven should be controlled to generate the bean roast profile that you want. thanks for your reply I would like to point out that I bake in a professional convection oven with digital temperature control (displaying the actual temperature in the chamber). the temperature that I have verified is inside the bean and was taken with a pointed thermometer and inserted inside the bean just out of the oven. Probably there is a difference but the range is the same my question is about the type of roasting in a convection oven. from what I understood by reading the site, in an oven it is not possible to reproduce a roasting curve as for a coffee roaster taking a cue from an article by jhon about oven roasting, it specifies these phases 375-400 F 5 minutes 350 F 5 minutes 325 F 5 minutes Beyond the temperature and minutes, I wanted to understand the difference between roasting with the above mentioned phases and instead reverse them in this way 325 F 5 minutes 350 F 5 minutes 375-400 F 5 minutes
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Post by Ben on Jan 19, 2021 11:53:33 GMT -5
Ah! Interesting technique, using a probe thermometer inserted into a bean. Keep in mind that most (all?) of the information about bean temperature that you're going to find is discussing the external temperature. One benefit of using external temperature is that you can take a bunch of readings really quickly and close the oven door to reduce heat loss.
You're right that a drum roaster curve can't be mapped directly in an oven, but a lot of the theory is similar.
The difference between the two sets of temperature you post is that in the first one, the beans are hit with more heat at the beginning, bringing up their temperature quicker at the start and then tapering off once they've started to actually roast, extending the flavor development part of the roast. In the second one, the initial heating from room temperature to the flavor development part will be slower and then it will go more quickly through that phase. This is a different roast and will result in a different end flavor.
Also, by putting the hottest part of the roast at the end, it's possible (probable?) that the center of the bean won't be roasted as completely as the nib closest to the surface. It's possible that this will make tasty chocolate, but there's no way to tell without testing different roasts and seeing what works for the specific bean you're using.
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