OK, I guess you want more than that. Like, you actually want to know what they are? Ok, I can do that. It’s pretty straight forward, and around the site, but the whole point of these Questions is to get much of the information in one place, so here goes.
Roasting. Unlike coffee which can lose 20% of its weight to moisture, cocoa starts out with much less moisture, and you end up with very little lost. So little in fact, that I totally discount it at all. It is usually only 1-2%.
Winnowing. This is by far the largest loss. At the absolute minimum there is 17% of the weight of the bean in the husk. This corresponds to ‘perfect’ winnowing efficiency, with a perfectly thin husked bean, of 83%. Most of the time I find this number is closer to 80%, or a 20% loss. On a particularly poorly prepped or heavy husked cocoa bean (think Papua New Guinea for a heavy husk), or one with lots of flats, a 25% loss is closer to the mark. When doing my estimating, I tend to round down, and be surprised when I have more nibs in my bowl.
Grinding. If you are using the Champion Juicer, you will lose a flat 6 oz to the Champion, regardless if you are doing 1 lb or 10 lbs. For this reason, many people (myself included) have taken to pre-heating the cocoa nibs, and adding them slowly to the Melanger (which has also been pre-heated). This way you don’t lose anything.
Refining. At this point, it would seem that your losses are at an end, but I’ve found that at this stage a little more moisture is lost. Sometimes up to 5%. And you have whatever you simply cannot get out of the bowl and off the rollers – usually an ounce or two at least.
There you go.
0-6 oz Grinding
And instead of trying to wrap your head around that EXACTLY and making how much you need to the ounce, I highly recommend just estimating your losses high (25% does just great) and make a little more than you want (4 oz) and you should have plenty.