Playing with dark roast on Ikawa - Page 2

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
Milligan (original poster)

#11: Post by Milligan (original poster) »

I had a chance to tailor a profile closer to the graph I posted earlier. I plateaued the temperature at 450F and let it ride for about 1min at 450F. First crack started around 7:22 and 407F. It ended at roughly 8:20 @ 422F. Second crack started at 9:30 at 448F. Rolling 2nd crack started at 10:00 450F. I dropped the Sumatra at 10:20 and 450F just as Happy Mug suggested. (20s after rolling 2nd or 40s after start of 2nd.) I was able to clearly hear 2nd crack now that I shifted the temperature back up.

Something I noticed going higher with the Ikawa is that the beans come out quite warm. I measured them at 115F after being ejected. So I broke out my old cooling box setup from the Behmor days to finish the cooling before jarring them.

GDM528

#12: Post by GDM528 »

Milligan wrote:You can still find the longer portion on their site under the general profiles called Morten Munchow https://www.ikawacoffee.com/pro-sample- ... rofiles/#!. Unfortunately, Ikawa seems to have removed the fast profile.
Thanks for the link. That led me to yet another profile from Rob Hoos, where he presented a "Masterclass" on creating roast profiles.
https://www.ikawacoffee.com/for-profess ... mperature/
What was interesting about the post: after much discussion a profile for the Ikawa Pro was presented with the asssertion that it would "closely mimic" a traditional sample roast from a drum roaster. Cool. Then, at the end of the article - without any discussion or explanation - they post a revised profile from Rob that's radically different...

So apparently there's a lot of ways to get from A to B, and with enough marketing language it's all good. Whatever floats your boat. This might explain why I treat my Ikawa like a cable TV tuner where I can change channels every ten minutes - and I do :)

GDM528

#13: Post by GDM528 »

Milligan wrote: Something I noticed going higher with the Ikawa is that the beans come out quite warm. I measured them at 115F after being ejected. So I broke out my old cooling box setup from the Behmor days to finish the cooling before jarring them.
I saw the Tim Wendelbow profile in the link you posted spends three minutes in cool-down, roughly double the cool-down in Ikawa's curated Home profiles. I tried opting for the shortest possible cool-down time to get the beans out of the chamber asap so I can cool them down faster... However, during actual operation my machine overrode my programmed one-minute cool-down and kept running until the inlet temperature was in the same temperature range you measured. I've observed that same behavior regardless of my ending temperature. I appreciate the machine is protecting itself from overheating, but now I'm wondering if Tim Wendelbow is on to something.

ira
Team HB

#14: Post by ira »

Mine seems to cool to 112 on the upper sensor.

GDM528

#15: Post by GDM528 »

After taste testing an 8-minute roast versus a 10-minute roast to get to a Full City dark level, I'm a bit perplexed. Same greens used for each roast, and each were similar curves: fast step followed by linear slope to a drop temperature in the 230-235C/ 445-455F range. Development times went from 2-ish minutes for the 8-minute roast to 3-ish minutes for the 10-min roast.

I was thinking the increased development time would reduce the acidity - but instead I noted slightly increased acidity with the longer roast time. The longer roast time was still good, but it didn't go in the direction I was expecting.

I got a few theories for what happened:
1) Simply scaling up the total roast time also increased the browning/caramelization time. That may have reduced sweetness enough to unmask the acidity.
2) I didn't spend enough time above whatever temperature I need to hit to break down the acidity. Is there is such a thing as 'acidity reduction temperature'?
3) An espresso shot tuning problem. Perhaps I need to extract a long roast differently than a short roast?

Any other theories/explanations?