Okay I cupped the 4 batches today. Now I know that since it is a blend, there are different amounts of coffees in each roast, but honestly they all tasted very similar as far as origin. There is probably 12 different SO coffees in this blend including Guatemala, Sumatra, and Kenya ETC.

Roast 1
This roast had the thinnest body of all. Flavors were muted, but that also muted some bad things too, overall it might have been the best cup because of this. I like coffee with a bit of body, but flavor is more important. Started watery, mild, then finished with hints of acidity, chocolate and just barely a touch of tobacco. 3.5/5

Roast 2
This cup has the most acidity present, but nothing like a typical SO African coffee. Hint of chocolate, hint of astringency. Hint of paper in the background. 3/5

Roast 3
This was the darkest tasting roast, and I normally do not aim to roast this dark, BUT after the roast flavors there was a sweetness to the cup. Flavors are dominated by the roast, not much clarity, but a subtle ashy sweetness on the finish wasn't too bad. 3/5

Roast 4
This might have been the worst cup, because for some reason it had a very present astringency to it. After that there was chocolate and a touch of paper, very little acidity.2/5

What I've learned from this:

Roast with a MET higher then 500 does not necessarily produce tobacco notes or scorch the coffee. Although a lot of my roasts do have tipping and some scorching.

I really need to focus on getting rid of the crash and flick after 1c. Not exactly sure how, but I think a mix of fan and reducing amps. I think this will get rid of the flatness and paper notes I get in cups.

Dark roasts can be sweet and tasty too.

Things to explore for my next roasts:

I'm not sure what benefit keeping the shoot open does for me, as it seems to artificially inflate MET.

Keeping amps high in the beginning and dropping the amps off as the roast goes is my new method to keep my RoR from sagging as people pointed out.

Fix crash and flick

Find out how high of an MET, or how much momentum I can push, while still maintaining declining ROR, and 1C near 7-8 mins.

Declining ROR is always going to happen. Not because I say so but because it is how thermodynamic heat transfer works (the delta T in the denominator).... Theoretically it should rise as an asymptote towards the MET...

But the flick and potential stalls happen because of latent energy - where the system absorbs excess energy and causes the temp to drop (throwing it off the asymptote curve).

IMHO - the biggest energy sink in the system at FC is water that is being driven out of the bean. Phase change takes up much energy. So for beans with much water content - you need to have the system charged up with energy so that that any energy sucked up will not cause the ROR to fall too much. Also - keeping the ROR still relatively high helps by giving enough room for ROR to drop a little. So keep ROR high and energy high until just about FC. (as I stated before I try to get there with 50-60% heat).

Conversely - if you prepare a system with excess energy and the coffee is dry (read: old & stale) the temp will flick upwards. Just finished a batch of dry, burnt coffee. That is what happens when you source badly...

Just a quick update of where I'm at.

With the silders you can see my power and fan settings at the top as the roast goes along. But my basic profile as of now is:

Charge 150g beans at 525 MET, 375 BT. Fan stays at 4, power goes to 0 till TP. I then crank to 9A, till around 280 BT (as suggested), then slowly back off as the roast progresses.

I was having issues with crash and flick. I was thinking that first crack was releasing heat and so I was lowering amps right as FC began. I learned that it is releasing water to make the temp drop, so I found out I need to keep my heat where its at and let it get through that beginning part of 1C. once 1C starts to roll along, I can slowly back off amps, but its tough because you dont want to crash it out too soon as you go through development.

Here are the last 2 batches I just did, I will taste them in the morn.

Unfortunately I lost my notes for my tastings of the graphs above, but from what I remember. The la minita had a slight green veggy flavor underneath, and the yirg was a little flat. Both were okay coffees but not great.....

I have probably done 30 roasts since then and have been struggling with crash in flick. I also notice the visual appearance of all my coffees are darker then I would like, have tipping, and some center line scorching, I do get roast notes and flat dullness in the cup.

I did 4 roasts last night, all with Happy Mugs natural Yirg.

In this graph I tried to follow the instruction on Mill City's blog 102:


Gas off for ~60 seconds
Air initially set for lowest airflow which keeps fan engaged. Mine reads around 25.
At end of drying (yellow/no green hues), turn up your air to medium (45 on my shop roaster).
Gas turned down 10-15% at about 45-60 seconds prior to anticipated 1st crack.
Turn air speed up to high (60-65% on my roaster).
Drop when you achieve level or roast desired

I thought the added use of fan could help smooth my crash and flick, but as most of you know, the quest's air dynamics are a bit goofy. My neighbor is a metal worker, and I'm thinking of asking him to modify the drum with holes in the back like in the quest mods thread.



As you can see i crashed and flicked. My tastes notes on this cup were, overly roasty, tar, flat. 2.5/5.

I then thought to myself "the lasts graphs I posted didn't have crash and flick, let me try that" I also wanted to lower the dark appearance of the roast so I tried charging a bit cooler at 480 MET.



Ah ha! No more crash and flick. So what I learned is for me to avoid crash and flick, I need to hold my power steady (6.5) amps as I enter first crack until it starts rolling. But I dont want a ton of pops going off because all that energy released crashes my ROR. So, once the cracks have some slight momentum, I start slowly lowering the power .5 amps at a time, and listen for the cracks to keep coming but not to slow of fast. At the very end of 1C I generally turn fan up to full just to try to blow chaf, and drop.

The tasting on this cup, had a bit more "fullness" or "roundness" to the body. It was a little bit roasty, but it was sweet. The SO flavors were very mild and not very present. 4/5 (in order for this cup to improve, it would need more SO fruity floral flavor and clarity, as well as a bit less roasty notes).

The beans on this roast were a little bit lighter, but still showed center line charring and tipping, So i tried charging even lower at 450 MET. I also read that centerline charring can be from too much heat during ramp, so I tried to just hold this at 8 amps, and tried keeping my MET below 525.



The tasting notes on this. It was the second best cup. It was similar to the one above, but had a thin body a touch less sweetness, but a bit more acid allowing a tiny bit more of the SO flavor to come out. So it was thinner, not as sweet, but notes of fruit. It was also a little bit to roasty. 4/5 (improvements would be if it had a tad more body and sweetness it would be 4.5/5 and if also the fruit popped with less roast it would be 5/5).

The last roast graph I did was pretty similar to the one above, but instead of using 8 amps to ramp, I used my normal 9amps to declining.



For some reason the tasting notes on this was the least successful. The cup tasted flat, empty, with traces of the above cups hidden in there. It was also roasty and had tipping and center line charring. I gave it a 2.5 out of 5.

I really appreciate everyone's help in my QUEST to achieve a great roast. If you made it this far, let me know what your thoughts are and any ideas on what I could be doing better.

I run my airflow at max for the entire roast. I also charge very hot.




I have a 2013 Quest. Think the thermocouples are the coffee shrub ones, forgot to ask the original owner.

My ROR sampling is at 3 seconds, also have smoothing turned on.

Once my BT stabilizes at the desired point, usually 460-480F with ET falling, I'll charge and cut my amps to 5.

Depending on how the BT is dropping into the turning point, I'll thrust up to 10 amps in advance of this change. In this graph, that adjustment was made at 1:20.

I keep amps at 10 until about 3:15-3:45 (depending on the coffee), then will begin reducing my power

HI Coffee Michael,

Thank you for sharing your profile with me. I tried something similar, but found the coffee came out flat and bit under developed (doesnt make sense right?). I will post the graph when I get back on my Laptop.

Now some cool upgrades.

I had my neighbor drill some holes in my drum to increase airflow. SImilar to Assfl in the quest mods thread. My drum has an open back fyi.

I will share some graphs with the new holes, However I still suffer from being able to understand how to bring enough momentum into 1C to avoid crash and flick.

Those holes may not get along too well with a small mocca sized bean.

Hey Tom, thanks for the comment. I read in your Mods thread someine said 3/16, so that's what we went with. I do agree they are a little big, but luckily being at the back, I have been okay so far. If I were to do it again I would go one size smaller.

You can always use a wire mesh spot welded or otherwise cemented to the area around the holes.

I've had a few peaberries stick in mine (mainly dry processed).

Just an update,

Roasting:

The biggest challenge I find so far is how to have enough momentum going into first crack. I find if I have too much momentum the cracks are super fast and all the release of energy crashes then flicks. Or if I dont have enough momentum the roast stalls and flat lines. It super hard to get it right. I also have been trying to never up the amps, only decrease.

Here is a Sweet Marias Panama that Bak Lo said he liked. This is BEFORE adding the holes.



This came out pretty nice. A 4/5. It sweet, has some very minor acidity to balance the cup. The body is a touch thin and it could be a bit more clear, but as a everyday coffee its nice.

Okay onto roasting with the holes.

I have been checking in the drum, and while the holes are not dropping a lot of beans, there is a bit more burn ash. Only 1 or 2 beans have managed to fall through, overall it is a success. I have been working with air flow.

The roaster is much more responsive to air flow, and also you can see my MET goes way higher now. I was really worried about my MET going so high, but I am finding that with the added air flow my chaff is much lighter, and my roasts are more even. I am having similar positive results from drilling the drum as others have claimed.

Here is a Sweet Marias Eithiopian blend, that came out pretty darn good. Its sweet, balanced, the fruity flavors are very subdued but hinted at. What interesting about this roast is the beans during first cracked were going crazy, Just tons of pops the whole way through. I was scared that it was going to crash, but luckly because I kept my amps, it just rode through. It did start to flick just a touch at the end so I dropped it.



I am getting better at understanding roasting since I first started this thread. A huge things to everyone that has taken the time to share their thoughts. While I dont feel im completely there (how to make it through first crack every time, I usually crash and flick).

Cheers.