Ask the Alchemist #138


Hi! I’ve only done chocolate from bean to bar twice but i noticed that the chocolate/cocoa liquor were too thick to make a nice mold. I have thought of shortening the conching time but the length I have done it was the best time i thought i had the right flavor. How do I ensure that the viscosity is just right next time?

This is really (nay impossible) to answer without more information. But there are only so many possibilities, so let’s just lay them out.

The most obvious to check is that the beans used are roasted, the sugar is granular and no other ingredients that have been added contain water. Very lightly roasted cocoa (5 minutes at 200 F) with brown sugar and ‘just a drop’ of vanilla extract was one that taught me no to take this part for granted. All of those items will introduce moisture into the chocolate that may or may not be enough to seize it but almost certainly will cause the viscosity to be higher than you want it.

You can use very lightly roasted cocoa but you still need to dry it for some time if you want the resulting chocolate to handle well. The same with any sugar. If it is clumpy and/or crawls it is too moist. Even my granulated sugar I heat to 150 F for 20-30 minutes to help drive off the last traces of moisture.

And vanilla extract. Everyone I have found is in alcohol which at the very minimum contains 3% water, and often much more. You have to use vanilla beans or powder (ground beans) if y want to add vanilla favor.

The next is to verify the recipe. My rule of thumb is at least 35% fat. And I estimate cocoa beans being 50% cocoa butter. The content can actually vary from as low as 45% on up to nearly 60%. What this means is that a 70% chocolate is about as low as you can go without thinking about adding extra cocoa butter and still hitting that estimated 35% fat (70% chocolate times 50% fat equals 35% in the bar). If you happen to have a low fat bean (fat content has ROUGH correlation Criollo content) like Cuyagua you might only be able to make it to an 75% chocolate before needing extra cocoa butter. On the other hand, many African beans(Ghana and Ivory Coast) and CCN-51 (Ecuador Pinchicha) have higher cocoa butter contents and allow you to go down to a 60% bar. Plus the more equatorially grown the beans are, the less viscous the cocoa butter will tend to be (all cocoa butter is not created equally).

Now we get to a little subtlety. I note I start getting these kind of trouble shooting questions this time of year…just as the tempering questions taper off. The pattern? Yep, the weather. In the summer, many people are molding up in the high 70’s (if not low 80’s), but now it is more often the low 70’s or high 60’s. The chocolate is cooling faster. It’s often going into cooler molds. The equipment is cooler too. Try and account for this. Work in a warmer room if you can. Warm up your molds and equipment (noting you don’t get them too hot) and just be aware. It might be that simple.

So you have done and checked all those things and everything seems to be in line. In that case, it’s time to just get the theory out of it and work on what works in practice. Bench top problem solving as it is sometimes called. Basically that means that we don’t know what is actually causing the problem but we are going to at least fix the symptom. I only have two things in my bag of tricks in this regard and both involve adding something to your chocolate that will reduce the viscosity. It’s really your choice which you choose.

You can try adding either more cocoa butter and/or lecithin. I like starting with lecithin. It will help bind any moisture in the chocolate, and if that is the issue, then you have learned something. Namely that something in your process needs to be examined to discover moisture is making it in. A teaspoon in a couple pounds of chocolate is a good start. If for some reason you don’t want to add lecithin (I rather hope it isn’t because you think it is ‘industrial waste’ – it’s not) due to soy allergies or something, then try the cocoa butter solution. I have yet to have it fail. Start with 5%, and see how that is. Then increase it 3-5% until it is the viscosity you want. At some point it WILL thin out. The flavor? Yeah, it may be a little different, but it may not. And at this point it is damage control, so you take what you can get. It’s the other reason I like lecithin first. It might fix it and won’t change the flavor at all.

Finally, I want to talk about ‘conching’ too much. There is good and bad here.

First off, good. You worked out you don’t want to continue the time in the melanger as you like the flavor. But in my experience, you have it backwards. More time results in the chocolate getting thicker once you get past a certain point. I’m not 100% sure why and it could well be a combination of reasons. Either the chocolate is picking up atmospheric water or it’s getting too fine. I saw one chocolate I was testing go from a good viscosity to VERY thick to the point it was like pudding….but it was in the melanger for 21 days (it started doing the pudding thing after about 7). Just recently I’ve been running some refining experiments and plotting time vs particle size with my new micrometer (more on this next week). The short of it is that I saw the viscosity drop down to about 20 um and then it leveled out until it hit roughly 10-12 um, but once it dipped under 10 um it started getting more viscous. Was it the particle size or time spend refining – who knows. It’s kind of difficult to split the variables. So I’ll just leave the observation out there.

Oh, and yeah, I mentioned the ‘bad’. Let’s try again use the right terms. If you are running a melanger (99.99%) of the people here, and you are leaving the tension on (99% of the people here), then you are not conching. You are refining. You are reducing particle size. I will grant that maybe you are conching, but you are also refining and the conching has nothing to do with the viscosity, so you should not be using the term as it is irrelevant. I’m really not trying to just be difficult and parse out words for the hell of it. Using the right terms make researching easier. And I personally find that it helps me make connections I otherwise might not if I understand what is going on, and part of real understanding is using the right terms. That’s all on that.

As for you next batch? Run down the list here. Ingredients. Water. Process. Percent fat. Is it all in line? If not, fix it and try again. If not, try more cocoa butter as it is your major unknown variable. 5% is my default suggestion to start with.

Send in your Ask the Alchemist questions to questions@chocolatealchemy.com

At this point I have one question in the queue.  This series only continues if you have questions and send them in.

1 Comment