To start with I may question if there would be an easily detectable difference between beans that have been roasted at 100-110C with the only difference being 18 or 20 minutes roasting time.

I may be wrong.

 

If you would like a suggestion:

Start with 10 minutes at 75C, raise temperature to 100C, hold for 15 minutes, raise to 130C hold for 10 minutes, discharge and cool immediatelty by blowing cold air (use a fan?).

You may try extending time at 130C to 15 minutes or raising the temp to 135C or 140C.

As always in life Your Mileage May Vary.

 

I've just started roasting new samples of Oko Caribe, trying a total of 8 combinations described below. Hopefully some of you will have suggestions for things to try.

First, about the equipment: I use perforated cheats in a commercial convection oven with excellent air flow, a single layer of beans on each pan. Prior to this I had used a Gene Roaster, a Behmor and a home oven. The Gene Cafe and oven get similar results at equivalent temperatures, often 20% below the reading needed for a similar roast profile on a conventional oven.

On to the specifics: in previous experiments I found that some cocoas do better with a drying / pre-heat phase. I use 20 minutes at 65C, the lowest available setting for my oven. For each temperature I have two sheets, one that goes through the pre-heating phase and one that does not. This time beans were removed at 18 and 20 minutes.

For the roast tests I was joined by a friend with a great palate. We hand-shelled beans from each sample and mixed nibs (I'm thinking of using a mortal & pestle next time) to get a representative sample without getting too wired.

 

Results:

pre-heated, 100C:

  18m: floral notes with peanut, coffee, fudge and brownie

  20m: more chocolate flavour, notes of espresso

100C:

  18m: sticky shells, beans still hard. Peanut, strong acid, green banana

  20m: brazil nuts (!?). fairly astringent but with a nice bourbon / malt, a slight smoke.

pre-heated, 110C:

  18m: nutty. spice notes: nutmeg, clove. some harsh acids. "warm"

  20m: minty, pepper aftertaste, less acidic, not very astringent.

110C:

  18m: pretzel (!?). Fruity acids, a favourite.

  20m: coconut. astringent; spice and espresso.

 

The next tests will be "no pre-heating, 22 minutes @ 100C" and "10m pre-heat, 12m @ 118C".

Is there anything else you would try for roast profiles or to change my protocol? Thanks in advance.