littlenut wrote:Hi Stephen, Thx for "repeating" yourself. I removed the bottom baffle from my Fortis several months ago because of one of your earlier posts. Tried it like that for a few months and didn't see a big benefit (nor any downside) so I reinstalled the baffle. What I did see was some additional radiant heating.
Skip forward ~6 months and I found my self wanting a shorter roasting time and a shorter Maillard (e.g. higher average RoR during Maillard), but I was right on the edge of scorching beans. I read this post about summing up your experience w/ removing the baffle and BAM I said to myself that that is exactly what I am looking for. I removed the baffle and roasted 10 batches today. Worked very well. Shorter roast times, shorter maillard, no scorching, Eliminated the steep fall-off right after the peak on the ROR Tb.
The purpose of this post is to say thanks for "repeating" yourself and why.
Thats great, thanks Tom for sharing your experience.
Currently im thinking I was somewhat wrong about airflow.
Ive since removed the little chaff collection tray as well, so now i have a drum in a box with a flame.
Needed to replace front bearing was getting stiff after so many 1000s of roasts. I took the opportunity to do full disassembly and clean.
Then i put it back together without the hopper / exhaust on faceplate. Used a clear bit of plastic to cover it after loading with 400g green beans and then ran it just to observe what the agitation is like.
Ive spoken before about how i thought the internal drum is a good design, its much better than i thought. It creates a really nice swarm in the air over to the left (clockwise drum rotation). The beans spend very little time piling on actual drum surface.
This lead me to rethink airflow based on what Rob Hoos is teaching with the Bullet and anotherjims Environment Temp teachings over the years.
charging at 205C
100% gas as beans falling in (1.0 kpa)
First 2 min no fan attached, hopper open for passive airflow (natural convection).
At 2 min attach fan duct using 1.5 on Kaldi chaff / fan box.
140 over 145C approaches start of yellow increase fan 2.0
155C end of yellow fan 2.5
170 over 175C one and only gas reduction to 70% (0.7 kpa - 0.65 kpa)
175 over 180C Increase fan 3.5 then let it go....
Depending on roast depth, fan goes to max (cooling mode) 15 to 30 sec before drop.
Im finally getting roasts that have no vegetal tastes, are a little lighter when ground compared to whole bean and highly aromatic.
Attached is an Ethiopian natural 400g.
Weight loss matches DTR at 13.3%
This is the first time ive got Eth natural to smell like top commercial roasters.
EDIT: Just to say that if one makes these mods then you are safe to use the roaster at its full capacity or maybe slightly more if you want a longer roast time. For me when I bought the Kaldi Classic their recommendation was 400g max batch size using Kenyan on YouTube video, which works great, gives solid data from the stock 3 mm probe which sits just left of centre in the face plate.