Universal conche, Ball mill, Roll Mill or Wet grinder
Hi everyone,
We are looking to expand our production line, we always thought we would just keep on going with bigger wet stone grinder all the way to a big Lehmann melangeur. But since we started looking deeper we am not so sure anymore.
We would like to know about your experience on Large (50kg and more) Wet Grinder, Ball Mill, Roll Mill and Universal.
-Which one can achieve a better texture or are they all equal on this point?
-Flavour wise, What is your opinion about each one?
-Maintenance, what are the advantage and disadvantage of each?
From what I understand the Universal can loose of its efficiently because of the wear and tear of the blades, which then need to be change pretty much every year. Is it correct?
Thank you very much in advance for taking the time.
Sorry for the very late reply, we’ve made a big move recently and it took us a while to settle in. I just wanted to say a big thank you — This gave us the knowledge to make an informed decision on our next production line. It’s been very useful to help us understand more about each different type of machines. We’re going ahead with the Universal as this sounds like the most suitable option for us.
Again many thanks Clay for taking the time to answer!
In The Netherlands a couple of years ago I visited the HQ of Royal Duyvis Wiener and one of the experiences I was treated to was a tasting of two chocolates made with identical recipes. The difference was that one batch was produced using a roll mill and the other with a ball mill. The question of whether one is better than another is, I think, a matter of preference and contact. Roll mills are used in making a lot of Swiss chocolate and ball mills in a lot of Belgian chocolate. My take is that unless you have a lot of experience and know exactly what to taste for then it’s extremely hard to detect any difference.
Of course, it’s also important to note that in the above examples pre-grinders and conches were involved so any output is modified by the machinery on either side of the primary refiner. I saw this with my own eyes when I visited Felchlin. There was a large liquor grinding operation and mixers that fed a large 5-roll mill that in turn fed a variety of conches.
There are a bunch of manufacturers who use so-called universals. They are called universals because they can grind, refine, and conche in the same device. These include Guittard, Bonnat, Pralus, and Fruition. I think we can agree that these companies all make well-made chocolate. When I visited Pralus I saw that he had three of them – two dedicated to making dark chocolates and one dedicated to milk chocolates.
Most small batch makers use their melangeurs as universals. Starting from nibs and sugar the melangeurs grind the ingredients into a coarse paste, refine them into smooth chocolate, and then “conche” the chocolate. I think melangeurs do a poor job of conching, at the very least they are inefficient, taking days to accomplish what can be done in a purpose-built conche in hours or less.
With respect to Universals, you can run them loose or tight. When you run them tight (with lots of pressure) you can finish a batch of chocolate very quickly. The risk you run is getting metal particles in the chocolate. This leads to the maintenance issue you mentioned. I can tell you that it’s a pain in the ass to replace the blades and rods in a universal. However, you can also run universals loose (little pressure). In this case processing times are typically at least 48 hours and can stretch to five days. When used this way the risk of getting metal particles in the chocolate is very low and the life of the blades and rods is measured in multiple years, as in five or more.
Ganging up a bunch of melangeurs is probably the least environmentally responsible way to scale production. Bryan Graham of Fruition told me that when we switched from three CocoaTown ECGC65s to one 250kg Macintyre his energy bill was cut by 60% while his production capacity more than doubled. You do need to take into account the water used for temperature control. A recirculating chiller reuses the water instead of using it once and dumping it.
But there is something I want to point out and that’s what appears to be the assumption that changing from one processing technology to another is the best approach. For example, you could add a small pre-grinder ($500–$3500) into your processing pipeline and reduce batch processing times – at least with respect to grinding and refining. You can add a proper conche (~€10,500) and reduce conching times from two days to two–three hours. Thus, you can keep the same central processing approach (the melangeur) and double your production capacity while improving quality and giving you more creative options. The pre-grinder and conche can handle the output of two 35kg/batch melangeurs.
Adding a small three-roll mill into the mix (~€12,000) add even more processing flexibility and can be used to ensure you’re not over-refining the chocolate in the melangeur. The roll-mill will also ensure that there are no particles above a certain size in the final product. This leads to a more even particle size distribution.
At the Jean-Marie Auboine school that’s the basic approach – liquor grinder into a Lehmann (50kg) through a small, slow-speed, three-roll mill, and then into a conche. It works very well. When I do classes with him we can produce at least two complete batches of chocolate (to molded bars) from beans in under three days.
I cannot stress the importance of thinking about incorporating a dedicated conching device that is not a grinder/refiner into the production mix. Dedicated conches are very efficient. While it is possible to fully conche a chocolate in a couple of hours, you don’t have to. You can focus on flavor development on the front end and then let the machine run to work on texture for as long as you want or need. In other words a dedicated conche gives you a lot of creative control you don’t have in other approaches.
With this approach you’re mimicking what larger manufacturers do by creating a production pipeline that can be used to parallelize production processes. You’re also not using a piece of machinery that was never designed for what you are using it for.
More importantly, from a scaling up perspective, you can look at swapping out machines based on production bottlenecks. When you are only using a melangeur or universal you have (simplistically) two choices – add another one or buy a bigger one. When you create a production path that incorporates different technologies you have more options when it comes to scaling.
Ball mills are very interesting devices. They tend to bar very expensive but they are efficient. However, it is important to be careful because you can go from something that is just slightly under-refined to something that is hopelessly over-refined in minutes.
And all of the above needs to be considered in terms of budget and space available.
For me, the decision about which way to go depends on what you’re making and how much of each product and in total you want to make. Finding the balance is important. My general recommendation is not to try to do everything in one machine. If you’re making milk/white chocolate then dedicating machinery for that production makes sense, rather than trying to do dark/milk/white in the same machine.
Finally, whenever doing metal-on-metal processing you are going to want to have a magnetic trap and a sieve and process the chocolate through both of these devices to remove any metal that might get into the chocolate. Even if you are doing stone-on-stone processing you should sieve the output to remove large particles of anything.