my first roasts... your opinion matters

[edtbjon]

I will trying using your method in controlling the air flow. I will also do my next batch light roast but the question is how long can I keep the coffee at 205 C for example without any temp rise before the drop without having stalling risk ? because I heard to insure bean development the roast has to continue for about 25% of the total roast time after FC.

The "25%" comes from Scott Rao, who recommends 20-25% from 1Cs (first crack start) for optimum development. I used to adhere to that rule, but have lately been going for shorter development times for light roasts with good results. It's really not possible to get 25% dev.time if I intend to drop before the end of first crack. If you plan for a light roast with a bit shorter development time, my opinion is that you should go for a bit longer time up to 1C. E.g. 7.30 to 1Cs is a short time, 9.00 should be OK.
If you go into 1C with a DeltaBT of 6-8C/min, you can easily keep that pace for say 90 sec, which should be around the end of 1C but still some pops going. That math would be 1Cs at say 200C and after 90 sec 210C, drop and a development time of 16-17%.
Slowing down too much at 1C and going for 25% puts you in the risk zone for getting baked notes, as you try to balance a very low DeltaBT. I do believe in going into 1C with some energy and I love to hear the 1C going off like a concentrated piece of fireworks.
I've also noticed that going for 25% (or so) with the perf drum is simply too much, i.e I get overdeveloped roasts. (Scott Rao's recommendations are based on much larger solid drum roasters.) I don't know if that holds true, but it's what I've noticed.

[Almulhem_900]

I will trying using your method in controlling the air flow. I will also do my next batch light roast but the question is how long can I keep the coffee at 205 C for example without any temp rise before the drop without having stalling risk ? because I heard to insure bean development the roast has to continue for about 25% of the total roast time after FC.

The "25%" comes from Scott Rao, who recommends 20-25% from 1Cs (first crack start) for optimum development. I used to adhere to that rule, but have lately been going for shorter development times for light roasts with good results. It's really not possible to get 25% dev.time if I intend to drop before the end of first crack. If you plan for a light roast with a bit shorter development time, my opinion is that you should go for a bit longer time up to 1C. E.g. 7.30 to 1Cs is a short time, 9.00 should be OK.
If you go into 1C with a DeltaBT of 6-8C/min, you can easily keep that pace for say 90 sec, which should be around the end of 1C but still some pops going. That math would be 1Cs at say 200C and after 90 sec 210C, drop and a development time of 16-17%.
Slowing down too much at 1C and going for 25% puts you in the risk zone for getting baked notes, as you try to balance a very low DeltaBT. I do believe in going into 1C with some energy and I love to hear the 1C going off like a concentrated piece of fireworks.
I've also noticed that going for 25% (or so) with the perf drum is simply too much, i.e I get overdeveloped roasts. (Scott Rao's recommendations are based on much larger solid drum roasters.) I don't know if that holds true, but it's what I've noticed.

Ture, I was referring to Scott approach of 25% DTR.

Thank you so much for the knowledge sharing. I'm so greatful.