I use the following as a guide and if you can stretch to buying a Temperature Data Logger then thats an additional measurable harbinger of the roast progress...
1. Weigh the bean batch to be roasted.
2. Preheat the roaster to around 100 C (ensures consistency with subsequent roasts).
3. Use a Stop-watch to provide a guide of when to expect roast progress milestones.
4. After the initial release of "chaff" and just prior to the start of 1st-Crack, some more chaff is released as the beans
swell and split the parchment.
5. Note the time when 1st-Crack starts, the Colour of the beans and then when 1st-Crack Rolls.
6. Note time when 1st-Crack Stops (dont worry about the odd late bean popping), and colour of the beans.
7. Closely observe the Colour Progression as the roast proceeds from the end of 1st-Crack towards 2nd-Crack.
8. Look for signs of smoke as the beans darken.... The roast can be halted any time now when the beans achieve the
colour your striving for.
9. Note time of the first snaps of 2nd-Crack... Go to be careful now as the roast can progress very quickly from this point
on.
10. Listen for the start of Continuous Snapping as 2nd-Crack starts to Roll.
11. Stop roast and immediately cool beans when Rolling 2nd-Crack has progressed to the point desired, but certainly
no further than 20-30 seconds otherwise you risk charcoal beans.
Additional steps that can be added in if you have a Temp. Data Logger....
3(a). Adjust Heat Source (if possible) so that Bean Mass Temperature increases at the rate of 4-5C per minute.
5(a). Note the Bean Mass Temperature when 1st Crack starts to Roll.
6(a). Reduce the Rate of Temperature Rise, if possible, by adjusting the Heat Source. Try and achieve a rate of 2.0C per
Minute.
9(a). Take particular note of the Temperature when approaching 2nd-Crack, when it starts and when Rolling 2nd-Crack
starts.
And thats about it :P. Maintain a Roast Log to record the milestones and Cupping Notes of each individual roast so that you can adjust future roasts to "fine-tune" the outcome to your flavour preference and then... Enjoy!
[smiley=laugh.gif]Cheers,
Mal.

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