A while ago, Dave Arnold [director of culinary technology at The French Culinary Institute] brought the pastry department a Santos conching machine. We were excited to see if we could make our own chocolate with it, so we used it as a class project and assigned our students the task of helping us figure out how to make chocolate for our own bars using the machine.
We ended up passing cocoa nibs through a Champion juicer until we had a smooth paste; it takes about four or five passings. We ground granulated sugar in a processor to a very fine powder and melted our cocoa butter over a bain maire. Then we added the cocoa paste to the conching machine and gradually added the cocoa butter while the machine was running. Once the mixture was smooth, we slowly added lecithin and then pure vanilla powder. After everything was incorporated, we very slowly added our sugar in about three batches, waiting until the sugar was completely incorporated and the machine was running smoothly before adding the next batch. We found that adding too much sugar at once can cool down the mixture too drastically.
Once all the ingredients have been added, the mixture is very grainy. We let the machine run, uncovered, for about 30 minutes to an hour. This allows any possible moisture build up to evaporate. We then placed the lid on the machine and let it run until we liked the product and it had the texture and flavor we wanted. During our testing period, we let a batch conch for one week in the machine. We checked the flavor and texture every day. It was amazing how much the flavor profile changed from day to day. Now when we make our chocolate, we will let it conch anywhere from 24 hours to six days. It took one testing experience to learn that it is crucial to temper the chocolate as soon as it is finished. Otherwise the chocolate develops sugar bloom.
The machine only turns out about two pounds of chocolate at a time, but we like how working on this project exposed our students to the chocolate making process in a very direct way. They learned so much from participating firsthand. And they were able to assess the taste, mouth feel, snap, sheen, and other important qualities to chocolate along the way. We hope to incorporate this project into all our Level 2 classes in the future. —Jürgen David