Using Steam in Roasting

[nawteeschocolates]

Hi Mr. Nanci, and thank you for letting us all come here. Because of you, I am learning more about my dream of making chocolate at home. And, because of you, I am reading, of all things, Food Technology books! Can't' believe it.

Anyway, I ran across information that stated steam was used as a "pre-treatment". I wanted to know what yout thougts were on this. Here is what the book said:

"Because the shell is relatively firmly attached to the cotyledons until the bean has been heated, some form of pretreatment is normally required before winnowing. this normally consisted of exposing the beans very rapidly to a source of intense heat provided by saturated steam or infrared radiation. this heats the surface, but the centre remains much cooler and no flavour changing reactions occur. water inside the bean evaporates and puffs out the shell making it separate much more easily when the bean breaks during the cracking procedure".

It is from "The Science of Chocolate" by S. T. Beckett. Found it in Google Books.

He went on to say about roasting the beans in the hulls "when the heat is applied, the cocoa butter melts. some of it is free enough to migrate into the shell, where it remains and is thrown awya following winnowing. it is estimated that up to .5% of cocoa butter is lost in this way. in addition extra energy is required to heat the nib through the shell. all energy used in heating the shell is also totally wasted. it is estimated that up to 44% extra energy is needed compared with the other forms of roasting".

I like the idea of heating up the hull and not effecting the nibs inside. I like the idea of pretreatment; it sounds logical and needed. Have you tried any pretreatment of your beans prior to roasting? If so, what was successful? I worried about the hull causing the taste of the nibs to become more bitter, since the hull has no sweetness to it, and can give the nibs more of an astringent flavor. I would like to keep as much of that out of the bean to begin with, so that when conching, I have a better product, due to the lower astringency of the chocolate liquor.

I have more questions, but, I thought I would start with this one. I am imagining ways to steam the beans, let them dry, cool down, and then roast. i would think that this would kill any bacteria and contamination that would be present in the hulls. And the steam would keep the off tastes from being transmitted into the bean. I am only dealing with the hull, here, and not trying to put water into the bean itself.

What are your thoughts? I greatly appreciate your efforts in this. Also, I wanted to just take a moment to say that I am keeping Penelope in my prayers for continued healing. And also for you, cause this is such a hard thing to go through. My best, always to you both!
Annette

[FeralOne]

"I am imagining ways to steam the beans, let them dry, cool down, and then roast. i would think that this would kill any bacteria and contamination that would be present in the hulls. And the steam would keep the off tastes from being transmitted into the bean"

At what point do you plan on cracking and winnowing? Before or after the roast? Even going through the steaming process then roasting you still have to remove the husk and by doing so you will create dust that in turn will end up in your steamed/roasted nibs. As I have understood the reasoning for steaming is simply to break away the husk from the nib more efficiently, not for microbial kill.

Please, bear with me, I am thinking out loud here. (And not really answering your questions, just adding more.)

I wonder if you steam the beans (to break away the husk), then crack and winnow, then wash/rinse them (washing away the contaminates), dry and then roast? Anyone think that would work?

I have been looking into the steaming thing over the last few months after reading about the salmonella outbreaks with Hershey's and Cadbury's. Nothing I have read so far indicates the use of steam for anything other than removing the husk, it seems that the roast is what kills the bacteria.

Anyone else have thoughts on this?

Andrea

[cheebs]

I just purchased a Verilux UV-C wand that I am using before and after winnowing. It goes somethng like this: after weighing and sorting the beans to eliminate flats, broken beans, "doubles," and other unacceptables, I spread the sorted beans on a baking sheet and use the wand according to instructions. After that I roast and winnow them, and again spread the nibs on a baking sheet and apply the UV-C light.
Finally, I apply the light to my molds and utensils before molding, and one last time to the molded bars or bonbons.

Before I had the UV-C wand I would preheat the oven to 550 deg F, wash the beans in hot water, and immediately transfer them wet to a pre-heated baking sheet. 90 seconds and then flip them over with a big spatula, another 90 seconds (3 minutes total). This generated a lot of steam. Afterwards I cooled and dried the beans on perforated baking sheets in a warm (98 deg) oven for as long as it took to dry them out, usually around an hour. Finally I roasted as normal.

By the way, the UV-C idea is not mine, I "borrowed" it from Clay Gordon.

[nawteeschocolates]

Yes, in the book that is mentioned in my first post, the steam and the roasting are sufficient to eliminate any microbes. When I read his information, he indicated that both were necessary. Now, I did not know that Hershey's had a problem with salmonella. And that has to be in a finished product. That raises the hairs on my neck! If, after their process, which I believe must incorporate all safety measures possible, they had a problem, I think I will look further into this.

Also, I like what you are doing, Cheebs. Where did you find the UV-C wand?

[nawteeschocolates]

Mr. Beckett goes on to say:

"...pretreatment allows shells to be removed before roasting. once shells are removed, nibs are broken into particles of uniform size, alternatively, the nibs are reducted to a paste, which is then roasted as a thin film. either method provides the manufacturer with better control over the roasting process, so that beans are more evenly roasted".

Something that has also caught my eye, is that a paste is made, and then roasted as a thin film. Hum...this would be very delicate, but, what would the taste differences be? I am afraid that Mr. Nanci has filled me with enthusiasm to see how this can turn out on an "at-home-level". I think I am enjoying the research more than I ever thought. I plan on testing this weekend and will post my results.

Prior to testing, I would like to ask for ideas on doing a thin film. Probably making a "butter" out of the paste, and spreading it on a cookie sheet, and as it roasts, turn over in sections with a spatula, roast the other side. I think that this is fine for test batches, or old women like me, who have time on their hands to experiement! LOL!

[nawteeschocolates]

I may as well ask more questions here. I understand that there are two mills used to break up the nibs. One is an "impact mill" and the other is a "ball mill".

Impact Mills

Impact mills work by hitting the cocoa nibs with fast moving pins or hammers. Sometimes the particles are hit against sieves or screens. The cocoa butter melts due to the heat from the impact and from the mill itself and any free fat together with the smaller particles pass through the sieve. The larger particles remain on the inside until broken by the next series of pins or hammers.


Has anyone done any "impacting" of their beans prior to grinding? Would this make the process faster of reducing the particle size, or would just putting it in the grinder render it sufficiently smaller?

Ball Mills

The majority of the world's cocoa is ground using ball mills, which can only grind liquids and so are normally preceded by impact mills. The mills contain large numbers of balls, which are made to bounce against each other, either by tumbling them by rotating the wall of their container or by a centrally rotating shaft with rods placed at intervals at right angles. The balls impact and rotate and any particles caught between them are broken by the crushing or pulled apart due to the shearing of the rotating action. The smaller particles move more quickly in the fat as it is pushed away by the moving balls, but the bigger ones are more likely to be milled as they move more slowly. With coarse cocoa liquor containing particles several hundred microns in diameter, the balls may be as large as 15mm. Where it is desired to have a finer liquor, a series of ball mills may be used, each one containing smaller balls, down to as small as 2 mm. More small balls will fit in the same space, so the chance of a particle being caught between two of them greatly increases. The agitator speed is also increased iwth the smaller balls.


Hum...it seems that everyone on this board is fine with the product that they are getting from the steps that Mr. Nanci has provided for us. This might be an unnecessary step, or, would it benefit the liquor if one developed a ball mill for just this step? Or, is using the Santha probably doing this as it conches? I understand that conching is not to reduce particle size, but to coat all the added ingredients, sugars and milk powders, with cocoa butter.

Any thoughts on this?

[nawteeschocolates]

Oh! One more question, if you can stand me!

Has anyone tried milling their dry ingredients separately from the liquor first, and then combining? I did read that it takes longer to conch that way, due to the milk solids. What about the ease of this application? Did it take longer to do the conching with one over the other? What about taste? How was it effected, and the texture, final product?

There are two methods of grinding the chocolate ingredients, namely fine ingredients and combined milling. In the "fine ingredient" process, the solid, non-fat components are milled separately and then added to the cocoa liquor, cocoa butter and other liquid ingredients in the conche.

In the combined milling, these ingredients are mixed with the cocoa liquor and some of the other fat before milling takes place. The two processes are likely to give a different flavour, as the sugar will pick up many of the aromas in the mill where it is being ground and in the latter case there is cocoa in close proximity.

[kellymon]

Hi, welcome to the forum:)
Answers to your questions might vary depending on your desired output volume and budget....
For instance, I am making about 3 pounds every few weeks so my methods might not work for you. On the other hand, we make a chocolate that we really like, and with a very low cost.
I have been cracking my roasted beans by placing them in 1 gallon zip lock bags and (carefully) beating with a block of wood.
It entices the beans to break into the small nibs as they are inclined to do, and renders the husks into very small particles which I then winnow.
My winnower is made from 3 inch ABS (plastic) pipe and a DeWalt vaccuum blower.
It works great, but the whole process while cheap and easy is time consuming, not a problem for my small volume.

Also, I do the whole process over several days: Roast, crack winnow etc.
When I am actually ready to start refining in the Santha I will heat the nibs again to 160f+ for a final microbe kill and also to make them easier to refine as I use very little cocoa butter.

Also, FWIW I use a low/slow roast... slowly increase temp to around 230-250f over 30 minutes and hold there for about 30-40 minutes. Others may have reasons to use otherwise, but that has worked better for me than higher more complicated patterns.
I also use a hand held infrared temperature gun (pyrometer) to monitor surface temps in all my steps. Cheap, accurate and easy.
robert

[Sebastian]

Couple of quick thoughts:
1) a uv wand won't sterilize a bean - there's simply too many crevasses in the shell - it'll give you a false sense of cleanliness
2) a heat/moisture pretreat can be very useful - it's commonly done and make the shell much easier to remove. legally you're allowed a max of 1.75% shell in your product, not because mfrs want to contaminate the chocolate, but because the shell's very, very difficult to remove entirely.
3) impact mills are also known as dry mills or air classified mills. very expensive. gives a different rheology than other mills.
4) can rather easily make your own ball mill - lots of designs on the internet, and i don't have time at the moment to go through them i'm afraid. each mill type h s their plusses and minuses - ball mills require a higher fat level to work well and often degreade the media resulting in slightly higher metal levels in your product (sounds worse than it usually is if you use good media).