I recently made my first 9 lb batch of dark chocolate (just beans and sugar) in my Santha Spectra 11. Prior to that I had only made 2 - 5 lbs for about a year. For my tastes, I observed that typically I would melange around 5-6 hours per pound of chocolate. That seemed to provide the smoothness that I liked while mellowing out the acids in the beans giving the chocolate great flavor. However, I melanged this 9 lb batch for 41 hours, which is about 4.5 hours per pound of chocolate. This produced a decent chocolate, but it has a solidly bitter bite at the start of tasting as well as a touch of astringency. That bitter bite is also a bit oddly flavored. Fortunately, this chocolate tastes great on the finish/back-end so it leaves me wanting to try more.

I'm wondering if melanging times when scaling-up batches of chocolate, in the same machine, should be linear or have folks experienced a non-linearity when scaling-up? I keep questioning whether I should've melanged for 45 - 54 hours, which would've amounted to 5-6 hours per lb of chocolate that I had previous success with. At 34 hours, the texture was still a bit gritty, but the flavor was atrocious. At 41 hours, the texture was pretty smooth and the flavor was considerably better. I decided to stop at 41 hours because I was concerned that the batch would be refined so much that it would taste gummy/plasticy. (I've never melanged that long with my Spectra 11.)

What have any of you been successful with regarding scaling-up in the same machine? Linear or non-linear melanging times?

These are very difficult questions. Mostly it’s because it’s not simple, and partly because I don’t have the concrete answer you desire. The short answer is that the time spent in the Melanger is not linear and is also not linear. See. Not much help. It is somewhat partly non-linear, but unfortunately it non-linear in a multi-variable way. What that translates to is that you have multiple non-linear processes that are going on (1st, 2nd and 3rd order chemical reactions plus particle reduction) at the same time and some are dependent on others and some are not. Further, they are temperature dependent, but to different degrees.

In more laymen’s terms that means the doubling the refining time doesn’t work if you double the amount of chocolate. And that is because each process deals with the doubled amount differently. Think of 5 cars going on a trip. 2 in one lane (cars 1 and 2), and 3 (cars A, B and C) in other lane. They have to stay in the order they start in. 2 is dependent the speed of 1. C is dependent B which is dependent on A. And 1 and A go at different speeds. Think of your batch size the terrain. Hills. And the flavor and texture of the chocolate are the positions of all the cars at a given time. If the terrain is mostly flat (1-2 lbs) all the cars will be grouped pretty well together at 40 hours. If the terrain is a little more steep, it may take 45 hours for car 1 (texture) to reach the same location, car 2 will be a little further behind, and A will be a little farther behind, but B and C will be farther behind again (safe driving distance after all). The result is that where they all are at 45 hours is similar to 40 hours, and recognizable. Basically the chocolate tastes close enough to the same.

But if on the next trip it’s very steep, it’s going to take car 1 50 hours to be where it needs to be. But everyone else (taste) is WAY behind. So the trip continues to 60 hours. Car 2 is about where it should be, but Car A is past where it was before, B is right on target, and C is lagging. The result? A totally different position for everyone with, and no way to get them into the same position since if one car moves they must all move. What’s one to do? We you can give the cars higher octane gas (higher heat) and the Letter group can keep up better. Oh, but that makes the Number group (refining) go a little faster too (they are also warmer so viscosity is lower). What to do? Maybe don’t add that extra cocoa butter at the beginning so the chocolate is a little thicker and add it at the end where it makes little difference.

Is that making sense? That in a way, each batch that is not exactly the same has the potential to be a little different. But that you DO have a few tools to make changes (temperature, time, recipe) and try and keep it at least similar.

The final thing I’ll say is that at some point, and as the trip continues, the lead cars start to slow down naturally. They plateau and start to kind of coast. You can only refine to so small a particle size and at least in the melangers we have, over refining rarely if ever happens. I have taken a tiny batch (1 lb) to the gummy stage in a few days, but I’ve run a larger batch (5 lbs) for 8 days with no sign of gummy at all. But at 10 days all the cars ran out of gas, coasted to a stop together, and I had pretty flavorless chocolate. But that was 10 DAYS (it was an experiment). Your goal is to go long enough that there is flavor left and in about the profile you want. But I’ve found you don’t have to worry about over refining.

Like I said. It’s a hard question with no good answer except that there is no easy answer. Oddly, I sometimes find that comforting. I hope you do to.