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Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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drgary
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#301: Post by drgary »

That's this curve on this very fruity natural. What I gather from Denis's posts is that he would roast that seem green faster and would encounter first crack but would still have similarly low or lower moisture loss.

The profile you just tried is still applying a lot of heat to the greens, but very gently. I would expect the VOC curve to be indicative of wanted chemical changes that would display fruit and sweetness, beyond hay, vinegar or toasted bread alone.

Here's an example of a drum roast that came out very juicy (sweet with an acidity backbone) on a Yemen. I'm running fan at 100% with a perforated drum and applying a lot of heat at the start. First crack didn't run long before I smelled fruity sweetness. But I think Denis would take that same green lighter.

Gary
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What I WOULD do for a good cup of coffee!

Cwilli62
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#302: Post by Cwilli62 »

I don't have the tools to measure the color or moisture of the beans. But I roasted a bunch of Ethopian coffees today and thought I would share pictures of different roasts. Still not sure what any of it means. I started the day with drgary's Ethiopia natural profile because I wast intruiged. However, after the first roast it looked underdeveloped to me so I decided to play around with different profiles for the day. Also, this is not a side by side, as I used different coffees for the different profiles. Ambient temp. at my place is 45 F and the altitude here is 6,691 ft. All coffees from Sweet Maria's.

edit: 65 g batches for all roasts

drgary's Ethiopia natural profile- dropped at 8:30
Coffee used: Ethiopia dry process Senna Katta Mountain



drgary's Ethiopia natural profile- profile run to the end of 10 min
Coffee used: Ethiopia Uraga Gogogu



GDM528's "I don't understand light roast people" profile
Coffee used: Ethiopia dry process Buno Dambi Uddo



Ikawa's Home Koke G1 atural profile
Coffee used: Ethiopia dry process Korate

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drgary
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#303: Post by drgary »

Casey, I think altitude makes a difference. When you tried the lighter roast, did you taste it? It will look light but should be roasted through if you are dropping by smell. One measurement you can take which will tell us level of roast is % moisture loss.
Gary
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What I WOULD do for a good cup of coffee!

Cwilli62
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#304: Post by Cwilli62 »

I just today roasted so I didn't try the coffee yet...and didn't eat a bean yet.

Moisture loss is about 10%. (On the Senna)

I do love light coffee. The light honey/tan color combined with he silver skin still being attached to a good portion of the beans is what mainly made me question the development.

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drgary
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#305: Post by drgary »

Try munching a bean. I'm not saying that's the perfect light roast profile but have found that since it's a long roast, it heats the beans evenly through, so although they look very light, taste may surprise you.

I managed a great light roast of a Kenya 11 days ago that tasted like cinnamon with a balance of sweetness and acidity out of the roasting tray. Now, it tastes like sweet black raspberry tea with a leather top note. With more rest the leather may recede. Weight loss was 12.2%. The pink bourbon natural noted with that profile is very sweet and fruity with no roast taste, but it's not underdeveloped. Weight loss was 10.7%.

A lighter roast may take some time to rest.
Gary
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What I WOULD do for a good cup of coffee!

Cwilli62
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#306: Post by Cwilli62 »

I got baking spices and mild blackberry with a touch of something like tobacco when eating a bean. Brewed a pour over today, just cuz', and though I could tell it was roasted yesterday (and the brew ran a bit fast), it wasn't bad! I'll be interested to taste it after sufficient resting.
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GDM528
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#307: Post by GDM528 »

These greens are fruity freaks: https://primegreencoffee.org/product/co ... n-natural/

Those greens turned my heavily-instrumented hubris into a chew-toy as it undermined my attempts to understand what I'm doing. So, of course I ordered more of them :)

I had heretofore been pretty convinced that measuring moisture rate of release (MRoR) is a more reliable indicator of first crack than trying to hear actual cracking sounds buried in the din of a jacked-up hair dryer...

I had also previously observed that natural processing will push out the first cracking timing, compared to the same greens with washed processing. Those previous tests were just a shot over the bow...

I did a roast level survey of the aftorementioned greens:

1) An 'ultralight' roast based on drgary's post here: IKAWA Home - profiles, but trimmed to drop at the 8-min mark.
Inlet setpoints:
0:30 112C
2:00 150C
3:30 182C
5:00 208C
6:30 227C
8:00 240C

2) A light roast intended to just hit first crack for a natural processed green, loosely derived from drgary's drum roast profile here: IKAWA Home - profiles. This drops at a lower temperature than the infamous "I-don't-understand-light-roast-people" profile, is one minute longer, but starts more gradually and drops about 5C/9F above first crack. It roughly matches the browing+development duration of some drum roast profiles I've been studying.
Inlet setpoints:
0:30 120C
2:00 166C
3:30 202C
5:00 229C
6:30 247C
8:00 255C

3) My usual dark roast go-to, intended to drop right at the doorstep of Full City.
Inlet setpoints:
0:30 170C
2:00 198C
3:30 222C
5:00 242C
6:30 258C
8:00 270C

Here's the BT and absolute humidity from those three profiles. BT in red, AH color-coded brown, dashed line is a washed version of the Pink Bourbon varietal. The labels describe the curve parameters: curvature, start, stop, and duration. batch size is always 65g and fan speed always 80% unless stated otherwise.:



The dashed line is for a washed version of the Pink Bourbon varietal from Columbia - not the same crop/farm however. The washed greens were added to the testing because the natural process greens were so 'crack resistant' - at least per my instruments, and I needed to confirm the humidity sensor wasn't malfunctioning. There was no sign of first crack in the moisture data for the natural light roast, BUT I did actually hear first crack about 45 seconds before the drop. So much for the moisture readings doing a better job than listening - least for these greens.

It wasn't until I got angry with these greens did I finally see a bit of a bump in the moisture release data for the natural process greens:



Interesting (meaning I don't understand why) that the slope of these natural greens is steadily downward, but the washed is flat during the browning phase.

Post- roast exterior colors:



Interesting how the washed version is largely the same exterior color as the natural version, despite significantly different development timing. Even weirder: moisture loss was the same between washed and natural.

Moisture Loss:
Ultralight = 10%
Light = 13%
Dark = 16%

I'm still trying to unwind what happened, but it does appear that drgary is onto something: starting very gently will significantly change the way moisture is released - across the entire roast. I have more respect for the drying phase in the IKAWA. This has me questioning the magnitude of the first setpoint in my profiles. Some of IKAWA's curated profiles start with a big thermal spike - is that really such a good idea?
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DenisEAF
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#308: Post by DenisEAF »

In 2020 I found that coffee from a roaster. Then in 2021 when i was on a gas roaster I got a few kg of it. It was really fruity back then, more like tropical, pineapple, sour tart, intense. Once rested to 3 weeks the flavors get nicer and the tart goes hand in hand with some strawberry/raspberry type of taste. You could describe it as grapes too, dark long ones, or dark grape juice.


Here are some pics, what I didnt like about this green is the size variation, I had to sort and split in 2 group, then roast them separate. Because of the size, and process (it's a natural but anaerobic) some beans will crack sooner others will crack late or not crack at all.

About washed vs natural, on my roest, washed crack faster 5:30 to 6 mins and natural crack around 6:30 (normal beans for me- kenya, ethiopia, colombia, honduras but higher altitude).

Regarding moisture of the beans (not live moisture) I use a cheap chinese calibrated moisture meter for coffee that I take moisture of the beans, and then i'm trying to land close to that value. For eg last roast is Honduras Parainema Washed has 10.3% moisture, dev:30 sec, weight loss 10.4%. Opened bag today after 13 days: got orange peel/candied orange, red apple, dark choc, cranberry juice.




GDM528
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#309: Post by GDM528 »

DenisEAF wrote: Here are some pics, what I didnt like about this green is the size variation, I had to sort and split in 2 group, then roast them separate. Because of the size, and process (it's a natural but anaerobic) some beans will crack sooner others will crack late or not crack at all.

About washed vs natural, on my roest, washed crack faster 5:30 to 6 mins and natural crack around 6:30 (normal beans for me- kenya, ethiopia, colombia, honduras but higher altitude).

Regarding moisture of the beans (not live moisture) I use a cheap chinese calibrated moisture meter for coffee that I take moisture of the beans, and then i'm trying to land close to that value. For eg last roast is Honduras Parainema Washed has 10.3% moisture, dev:30 sec, weight loss 10.4%. Opened bag today after 13 days: got orange peel/candied orange, red apple, dark choc, cranberry juice.
The farm/processing center must've upgraded their greens sorting since your purchase, as my bag was quite uniform (photo in post #297), and the roasted results were also reasonably uniform. Alas the vendor only had two bags left, but it's reassuring to know they may come back in stock again someday.

Size sorting the greens is a great idea however, especially for the IKAWA roasters. Yet another rabbit-hole to fall into...

If I can figure out how to calibrate it, I get a very distinctive absolute humidity reading when I stuff my exhaust gas analyzer into a bag of greens.

Apologies for not being familiar with Artisan: is the vertical red line on your graph where you stopped the roast (7:24)?

DenisEAF
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#310: Post by DenisEAF »

I think I was live roasting there following a background roast log.

Drop would be 201C there BT, but this was when i was roasting on a single wall drum with gas, that you can't roast fast with due to the way heat works in it. I mean you can't really get to FC in 5-6 mins w/o defects on it, on other roasters you can.