Bean to bar viscosity after adding sugar

I'm experimenting with some conacado Dominican Republic at home, and after grinding for 24 hours I had super low viscosity (almost like water) with a super-small micron size. After adding sugar (30% to make a 70% bar) and grinding for another 24 hours, my micron size came back down to normal levels but my temp had shot up to 124F and the chocolate became super viscous and was pulling from the bottom of the grinder. I wanted to conch another day or so but I was worried the chocolate would seize up the machine, so I pulled it from the grinder and tempered and molded it. It has an astringent quality that I think conching for another day or so would've helped.

I was using a small batch (about 1.5lbs) in a tabletop grinder. Was I adding sugar too early? Is there anything I can do temperature-wise? I really don't want to add cocoa butter if I can avoid it. I can also provide pictures if that helps.

Why don't you want to add cocoa butter?

As I see it, it's a huge mistake that most people make when starting out. Learn how to make chocolate "the proper way" and then, when you have experience making it - and making it consistently, especially at this small scale when the machines are really underpowered - you can start to back out on other ingredients.

Thanks for responding! I guess at this stage I'm trying to mitigate the number of variables. I'm still trying to figure out the roast, let alone grinding times. I have found these beans to have quite a lot of cocoa butter in them naturally, and only after 24 hours with sugar added did it start to really thicken up. Cocoa butter would thin it back down, correct?

Yes, cocoa butter will thin it back down. When you say "quite a bit of cocoa butter in them naturally" do you know what the fat level is? Beans can range for 45-55% fat and the fat can have different hardnesses (melting points) so two beans with the same fat content might have different viscosities at different temperatures.

Limiting the number of variables makes sense to some extent but if, by eliminating a variable, you make the basic process much more difficult then I would add in the other variable - the added cocoa butter - so that at least processing and molding can proceed.

You might also check to make sure that the sugar is absolutely dry. One way to do that is to prerefine it in a food processor. If moisture starts to form on the lid then the sugar is not dry and the small amount of moisture in it could be binding with the chocolate, thickening it up.

No, I'm not sure what the fat content is - I guess I'm going off of how thin the liquor is before I'm adding sugar. Thanks for the sugar tip and I'll take a look at buying cocoa butter to aid in the thickness problems I'm having. I'm also wondering if grinding with sugar included for less than 24 hours would help. Pre-ground sugar (like in a food processor like you suggested) shouldn't take all that long in the grinder to dissolve right?

Okay - so it may look thin to you but if you had experience working with beans from 10 different origins you don't know where it fits relative to others.

Sugar doesn't dissolve, you're grinding the particles down. Yes, in a wet-mill style grinder pre-refining the sugar should reduce the amount of time required to finish grinding. If you purchase pre-refined sugar you must be sure that it contains no anti-caking agent; commercial confectionery sugar often has up to 3% corn or other starch in it and that's a no go when it comes to making chocolate.

Oh it doesn't dissolve?? Is there a good chemistry book that discusses the molecular structure of cacao? And speaking of books, is there a good resource for bean-to-bar chocolate making?

I'd seen this book but that's a pretty hefty price - I'll buy it if it's worth it though.

http://www.amazon.com/Production-Processing-Technology-Emmanuel-Afoakwa/dp/1466598239/

I'd heard about confectionery sugar having corn starch so I'm glad I'm using regular granulated sugar.

I would suggest The Science of Chocolate by Stephen T Beckett. Ithas a lot of useful information at a decent price.

It is my understanding that the longer you grind, the more fat is released from cocoa particles, which will reduce viscosity.Whether that applies to your case I have no idea, but perhaps 24 hours with such a small batch is too long,but that also depends ongetting a good bean and hitting theroast right.

Thanks Adrian!

Can you cut 50 of your beans in half and count how many are purplish tinted in color inside? Can you post your formula you're using, and are you using lecithin? If your recipe is simply 70% beans and 30% sugar, i'm guestimating your fat level is approximately 32% (but that's why i asked you to count purple beans, to help understand how fermented they are, which impacts fat level). At 32% fat - regardless of how well fermented your beans are - if you're not using an emulsifier - such as lecithin for example - i'm afraid your chocolate is going to be thick (viscous). If that's the case, i suggest adding 0.5% fluid lecithin a couple of hours after you've added the sugar.

Right now it's literally just 70% roasted nibs and granulated sugar, added after 24 hours of grinding. Can you do a cut test on dried beans?

absolutely. I'll tell you right now however that adding lecithin will fix that problem. If you've got a philosophical against using lecithin, you're only solution is to add cocoa butter.

Hi Sebastian,

after I read this, i got curious and cut 50 of the beans i have in half. Almost all of them are purple/purpilsh inside. i was wondering what this tells you about the beans

I was curious about this as well.

I searched "purple cocoa bean quality" and found this useful page.

http://www.ccib.gov.tt/node/116

Fully purple bean is a bright purple colour, and may have the cheesy texture of slately beans. Such beans are insufficiently fermented and are rarely found when normal large - scale methods are properly used

Dear David,

The Conacado beans are normally well fermented but quite acidic. So you would need to roast them adequately and than grind them for the first 12 hours (we roast at 130 degrees C for around 45 minutes, using a ball roast). During this first stage additional heat could be added in order to reduce the acidity further. The cocoa mass than reaches a 75 degrees C. After this stage you can (should) add some extra cocoa butter (3-5%) and than add the sugar, grind for an extra 2 days and you'll have a super chocolate.

Best!

Rodney Nikkels

Wow thank you so much for specific roasting times/temps!

Depending on what kind of grinder you are using, excessive grinding will exponentially increase the aggregate surface area of the particles in the chocolate. When this happens, there can be insufficient cocoa butter to fully coat all of the particles ---this results in a significant viscosity increase. As the viscosity increases, the amount of horsepower energy converted into heat goes up, driving up the temperature of the chocolate. Remember, when you measure micron size, you are just defining the largest particle in the chocolate --- all of the other particles are smaller than the micron measurement. Therefore, micron readings don't tell you anything about the particle size distribution. Excessive ground chocolate will also have a cloying sensation in the mouth as the very small particles actually plug up / get stuck in pores of the tongue.

Very interesting. So adding cocoa butter will keep viscosity down. How can you tell if you're grinding excessively?

it tells you a great deal, actually, but the most relevant bit for this discussion is that those beans haven't been particularly well fermented, and their fat will be low. In addition to being more bitter and less chocolate flavor wise, you'll need to compensate for the lower fat of the beans by adding more liquid cocoa butter to achieve proper viscosity.