Conching and refining chocolate at home
I have noted that there tends to be some confusion when people talk about conching and refining chocolate. It probably does not help that I have even put the two processes on the same page. But I want you to understand that they are two separate processes with two different goals in mind. Sometimes conching and refining can happen at the same time, but they do not have to and often you do not want them to. Some definitions are probably in order.
Conch comes from the Spanish word concha, which means shell. The name "conching" arose because the original vessel used to hold the chocolate was shaped like a conch shell. Conching is a modern process used in making chocolate The characteristic taste, smell and texture (and by this, I mean general mouthfeel, not particle size) of chocolate are developed at this stage.
The process of reducing the particle sizes of both cocoa solids and sugar crystals in finished chocolate. The goal is somewhere 20-30 microns. Your tongue loses its ability to determine texture and grittiness at around 50 microns. Under about 15 microns the chocolate can get gummy. We will worry about over refining when we get there. We can only hope for that problem.
With that all said, what we have found that works remarkable well for both Refining and Conching is the Stone Melanger by Santha. If you notice, it looks a lot like a commerical old style Melangeur.
|Santha Wet Grinder||Old Style Melangeur|
On a weekly basis I get asked if there is another less expensive way to refine chocolate at home. Trust me (hopefully you do), if I knew of one, you would know about it. Right now, to the best of my knowledge, the Melanger by Santha is it. At one point we tested out another wet grinder by Sharp. Although the list is by no means conclusive, different things we have and failed to use as chocolate refiner are as follows:
- Ice cream maker
- Blenders (many makes and models)
- Juicers (including the Champion, which is the only juicer we know of that will liquify the cocoa nibs, but still doesn't touch sugar)
- The oh so romantic Mortar and pestle
- Ball mills
- Rock tumblers (with steel shot)
There might be more, but again, if we had found another way, you would be the first to know.
As for the Wet Grinder (as it was formerly known) it was only capable of running an hour before the motor started overheating. With a little testing we were able to suggest some modifications to Santha that would allow the motor to run continuously as needed for chocolate. They were happy to accomodate Chocolate Alchemy and we are now the sole supplier of Santha wet grinders that you can use for chocolate refining. (Side note: if you happen to have an "original" Santha, you can always modify it to run continuously. Just go to How to Hack your Santha) Future modifications may even include heater so it can act as a heated conch and maybe even a tempering machine - talk about an all in one chocolate machine.
The current vent modified cover from Santha looks like this:
The Santha has a heavy motor that rotates a granite slab (10 lbs) and two large heavy (7.25 lb total) granite rollers at about 150 rpm. The whole thing is just under 50lbs! Oh, and I just saw they say it is "light weight" - don't you believe them - this thing is a heavy duty monster - and that is great! Really, the picutres just do not due it is justice. Just have a look.
So, how do you use the Santha? Initially preheat (and melt) my ingredient in the over to about 120 F, but you can as easily point a hair dryer at it for 2-3 minutes. After the first hour though, the chocolate becomes more liquid like and the whole thing generates enough heat by friction that additional heat is not really needed. After that, I have found a differance in texture after every hour, with "smooth" chocolate occuring around 10-14 hours. With the freshness and quality of ingredients we are using, I have found no degredation in flavor or signs of over-refining after 24 hours of refining and I have word from various customers that it performs great up to 36 hours (not that there is a problem after that, just that they refined that long). It is that simple. If you need to stop the refining, just do. It will not hurt a thing. I turn mine off at night, put the bowl into a pre-heated oven (about 150 F, with the oven then turned off) and let it set overnight. It is usually still liquid in the morning and I can just restart the refining. If it does solidify, just turn the oven on about 150-175 and melt the chocolate. Take the cover off for better heat transfer and so you don't melt it. Finally, the bowl is held together my an epoxy that has a maximum temperature limit of about 170 F. It can handle a 200F for a short time, just don't let everything get that hot.
My latest batch of chocolate was two pounds of milk chocolate.
8 oz Ghana Forastero liqueur (melted) (18.8%)
8 oz cocoa butter (melted) (24.4%)
8 oz non-fat dry milk powder (18.8%)
16 oz sugar (37.6%)
2 g lecithin (0.2 %)
1/2 vanilla pod (split and soaked in the cocoa butter 1 hour)
After refining for 9 hours, at 1 hour increments, there was no noticeable grit left from the sugar. During that time, some conching occurred to - there was a marked increase in viscosity (which is what is supposed to happen) and some of the sharper flavors at the beginning have mostly disappeared. Conching has to occur to some degree as there is tremendous shear where the 120 rpm granite rollers rotate against the lower spinning granite slab.
After about 5 hours you can see most of the grit has been refined away, but you should note that there is not a lot of gloss to the chocolate. It means is it not ready yet.
This is the chocolate all finished. There is a nice high gloss, and you can even see the chocolate sort of spinning off of the granite rollers.
Of course, the real test of whether it is done or not is "do you like it?" and "is it smooth enough?". Only you can answer those questions.
In addtition to the above basic instructions, there is also the Chocolate Melanger Instructions and tips which give a bit more detail on how to use (and not abuse) the Melanger.
In the mean time, the following will give you a bit more detail as to what in involved in refining and conching.
The process involves heating and mixing for several hours to several days the ingredients of chocolate - cocoa, cocoa butter, sugar, lecithen and and any "flavoring" such as vanilla or essential oils. For milk chocolate, dry milk powder is also included in the mix. (don't try to use liquid milk, it will seize on you). During conching, the chocolate is heated to temperatures of 110 to 180 F, sometimes externally, sometimes just from friction. In the "industry" many Milk chocolates are heated to temperatures over 160 F to allow the lactose crystals to transition into amorphous lactose. This transition is often why milk chocolate has that soft and silky mouthfeel. Some people (both commercial and at home) don't do this, and that is fine. Especially at home, it is your choice. I find the 140 F often reached in the Melanger does just fine. Regardless, during Conching the sharp taste of the fresh cocoa slowly disappears. At the same time the acidity and bitterness of cocoa are lost and the moisture content is reduced (there is actually debate over this) and the delicious chocolate flavor becomes fully developed. Simultaneously in the process, the smoothing of the cocoa and sugar particles takes place with cocoa butter forming around each of the small particles. This is different from refining really. The particles of sugar and cocoa are smoothed out in conching but not substaintial reduced in size. Conching is done for several hours or up to three days. Finally, there are basically two thoughts on conching - low and high shear. When conching was discovered, there was only low shear, and this is probably why it could take up to 3 days. With modern equipment, there have been a number of conching advancements, notably high shear conches. These supposedly (there agian is great debate) can conch a batch of chocolate in under 15 minutes. The high shear causes the volotile components to be quickly liberate from the cocoa mass.
There is no real right way or amount of time to conch. It is up to you and what you want your final chocolate to be like. All I can do is give you certain guidelines. Certain Criollo cocoa beans are choosen because they are bright and fruity. You would not really want to conch that for 3 days because you are just going to drive off those qualities that you choose the bean for in the first place. And you will need to keep balance in mind in that desirable and undesireable compounds are driven off during conching. The trick is to find that combination of conditions (low or high shear, high or low heat, short or long time) that give the chocolate flavor you want. Conching is probably the least understood process in modern chocolate making and consequently the most Alchemical of the processes. Finally, try not to worry too much over it. Even if you chocolate is not exactly like to want it, it is still going to be good, primarily because you are using fresh quality cocoa beans.
Right now there are no heated home conchs, only the Santha that conchs as it refines. The present plan is that we can further modify the Santha to be heated. We are working on that and will keep everyone up to date.