I have been experimenting with various roasting techniques and temperature profiles and I wanted to share some of the results with you.Some time ago you may remember I received a visit from fellow alchemist Frederick Shilling of Dagoba Chocolate. I had just finished making into liqueur a 3 lb batch of cocoa beans that I had roasted at 525 F for 15 minutes on my grill. We both tasted it a felt it was a bit over-roasted. He happens to really like barely roasted beans, where you have a lot of the sourness and acidity left. Dagoba roasts at about 250 F for 20-25 minutes. I on the other hand like my beans a bit more roasted. Just to be fair, I tried lowering the temperature of my next batch to see what I thought. Truthfully, I could not bring myself to drop the grill temperature to 250, but I did lower it to 350 F and roasted for about 23 minutes. It just didn't feel right. I never reach the point where any of the beans popped or cracked but they did crack and winnow just fine. Their final temperature was about 230F, right in the range of Frederick's cocoa beans and had the same sharpish flavor. This got me thinking. I roasted 100 degrees hotter but ended up at the same place. Why was that? Well, what I have come to conclude is that all the data out there about roasting cocoa beans is for hundreds if not thousands of pounds and that they are using huge roasters with large heat capacities. We here on the home front are limited in that respect, so what we lack in thermal mass we have to partly make up for in temperature and batch size control. So I tried a test. I heated my grill to 450 F. Cellulose burns at 451 F (remember Bradbury's Fahrenheit 451?) As soon as I put my drum in, the temperature dropped 100 degrees so I applied more heat and brought it quick back to 450, then lowered my heat input as the temperature came back up. The roast still took about 20 minutes. At that point the smell was chocolatey and I had a pop or two. The final temperature was about 280 F (for the bean mass, not the grill) and the resulting liqueur has no burned flavor at all, just good chocolate flavor. What does that mean for you at home? These are the conclusions I have come to:
- 550 f really is to hot of an ambient temperature to roast in. Where as the beans were not burned, a burned flavor started to come through. I think the husk started to char just a little, or maybe just stuff on the grill. Keep your roasts 450 F or less.
- Pick a target temperature for your beans.
- 210-230 F for barely roasted
- 250-260 for medium roast
- 280-290 for full roast
- 310 for very roasted (I will not say over-roasted, it is your chocolate and you get to decide)
- Roast around 15-20 minutes for a test roast.
- If you are at 450 F grill temperature and your roast is under-roasted, decrease your batch size
- If it is over roasted, either roast more beans or decrease your initial grill temperature.
- Once you hit a roast level you like, adjust your time to suit the flavor you want out of your beans. Overly long roast times will tend to mute flavors. Too short of a time may well be sour and/or uneven.
On my grill, I can roast 3 pounds to 260 F in 20 minutes. I like this profile quite a bit, although the flavors are just starting to mute a little. I may need to pull my batch size back half a pound so that I can shorten my overall roast time a little And finally, remember, each bean will be different. I roast them all before offering them and will try to give you an idea where I like them roasted. But in the long run, it is up to you to decide what you want your chocolate to be like. My suggestions are just that; my suggestions. They are not right or wrong. You are your own Chocolate Alchemist!