The next step in the process is to grind the roasted nibs into a smooth, uniform mass. You want to take the nibs and "refine" the cocoa solids into the smallest possible size particles that you can. The human tongue can detect particles larger than 30 microns (about a thousandth of an inch), so the smaller they get, the smoother the final product.
The best possible piece of equipment you could use for this would be a commercial chocolate melangeur
or Indian flour grinder
. Unfortunately, these are expensive and hard to obtain. You can also use a juicer, with the folks online generally picking a Champion brand juicer
. Again, a masticating juicer is an expensive piece of equipment, and not something one would generally be expected to have at home.
So, in the stead of the more expensive machines, it's possible to use a standard blade-type coffee/spice grinder to refine the chocolate. It's unlikely that the grinder will be able to refine the mass all the way down to 30 microns, so the resulting chocolate might have a "sandy" mouthfeel; don't despair, the taste will still be excellent!
First, we need to refine the desired sweetener. To do this, figure out how much chocolate you want to end up with (about 100 grams is really the maximum that my grinder can handle), and work from there. A 100 gram batch of 60% dark chocolate will require 60 grams of nibs and 40 grams of sugar. Add the sugar to the spice grinder and grind it until it's a superfine powder.
Add in the nibs.
They'll need to be processed for about 5 minutes total. If your spice grinder is like mine (cheap), it can't handle 5 minutes of constant on-time. Grind for about a minute at a time, and give the gadget some cool-down time if it should start to feel warm.
At first, the grinder will reduce the nibs to a coffee ground-like consistency, but as the blade continues to grind and heat the mass the cocoa butter will melt and be released. This will cause the mass to take on a thick, tar-like appearance - at this stage, it will be necessary to scrape up the mass that is stuck to the bottom and sides of the grinder.
The grinding is done when the mass flows easily.
When the chocolate is refined as much as possible, spices can be added. Make sure that they're thoroughly mixed into the mass!
If the chocolate needs thinning, small amounts of cocoa butter can also be added. Try to keep the total amount of additional cocoa butter below 10% of the total weight (no more than 10 grams for a 100 gram batch of chocolate).