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Lack of airflow or stale beans (or other issues)? Kaldi roaster troubleshooting.
DoubleK
Top  #1 Print Post
Posted on 02/25/2017 5:10 PM
Hi all,

I've gotten some pretty good roast profile charts the last few times. (Compare the earlier roasts to the last two and you'll notice a marked improvement) The only problem is that the coffee tastes flat. The last few have tasted decent enough, sweet (caramelly) and good body, but just not quite right (I want to say it should be more dry and bright, but I don't think those are the right descriptors - don't have any cupping training).

It seems to me like I've got a pretty good temperature profile dialed in (I've included shots of my roaster and data logging setup as well), so it's frustrating that my coffee remains disappointing (it's been not too great for way too long now). The main variable I can't modify is airflow, since my roaster doesn't have a fan to control (there are vents to naturally aspirate from the bottom and most of the airflow will go out the opening in the drum near the top). That being said, considering that many people seem to get good roasts from their whirly pop, airflow can't be my only problem.

Therefore, it has occurred to me consider the possibility that it could be the age of the coffee I am using. I've got Ethiopian and Sumatran left over from the fall (October?) of 2015 and the Brazilian is from March of last year. Given that they might've sat around before they were delivered to me, they might be somewhat older. Now I know that green beans can last a while, but I think I might be pushing it a little too much and I was wondering if anyone here would like to chime in on whether or not that could be the main problem.

That being said, I'll likely be able to get new greens soon and maybe I can get some roasted by someone who knows what he's doing to compare. Maybe that'll take care of my problem. Otherwise, I may just start looking into a Hottop or better (feel free to make suggestions). I'm tired of disappointing coffee.

As always, I appreciate the advice.

Regards,
Pierre
DoubleK attached the following images:
feb_22_-_brazil_yellow_bourbon.png feb_12_2017_-_ethiopian_limu.png jan_12_2017_-_ethiopian_limu.png jan_2_2017_-_ethiopian_and_colombian.png dec_12_2016_-_colombian_chalos.png img_2426_1.jpg
 
jkoll42
Top  #2 Print Post
Posted on 02/25/2017 6:16 PM
Just looking at the curve quickly it doesn't seem way out of whack. It could certainly be the beans - depending on where they came from the could have been old stock to begin with or not very great even when they were fresh!

There' a few things you can do to try and eliminate the bean variable. You can just order a small amount of beans from a reputable vendor who consistently sends out top quality beans and lists arrival dates. I'm sure there are others but Sweetmarias would be one example.

You could also send someone who has their roster dialed in and consistent some of the beans. If they have bad results than it's likely the beans.

Years back there was a member who thought his roasting was the issue with horrible pulling shots. To eliminate one variable he DHL'd samples of the roasts (from Pakistan lol). Everything pulled fine on my equipment - that left the grinder. New grinder imported and all was good!
Jon
-Jon
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
 
allenb
Top  #3 Print Post
Posted on 02/25/2017 7:15 PM

Quote

Therefore, it has occurred to me consider the possibility that it could be the age of the coffee I am using. I've got Ethiopian and Sumatran left over from the fall (October?) of 2015 and the Brazilian is from March of last year. Given that they might've sat around before they were delivered to me, they might be somewhat older. Now I know that green beans can last a while, but I think I might be pushing it a little too much and I was wondering if anyone here would like to chime in on whether or not that could be the main problem.


I've roasted for close to 21 years and have had ample experience in seeing differences in the cup related to shelf life of green coffee. From delivery of green coffee to roasting: maximum of 4 months unless vacuum sealed and frozen. After 4 months, I've noticed a very rapid decline in cup quality. Some coffee's are able to last longer depending on when it was processed and how well it was processed. There's lots of other variables that affect how long a green coffee can sit on a shelf and remain unchanged as in where you're going to be storing the coffee, humidity, local odors from cooking, smoking, etc...

I've never found a green coffee to remain true to it's original cup quality, beyond 4 months, unless vacuum sealed/frozen.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
DoubleK
Top  #4 Print Post
Posted on 02/25/2017 7:48 PM

Quote



I've roasted for close to 21 years and have had ample experience in seeing differences in the cup related to shelf life of green coffee. From delivery of green coffee to roasting: maximum of 4 months unless vacuum sealed and frozen. After 4 months, I've noticed a very rapid decline in cup quality. Some coffee's are able to last longer depending on when it was processed and how well it was processed. There's lots of other variables that affect how long a green coffee can sit on a shelf and remain unchanged as in where you're going to be storing the coffee, humidity, local odors from cooking, smoking, etc...

I've never found a green coffee to remain true to it's original cup quality, beyond 4 months, unless vacuum sealed/frozen.

Allen


Yeah... Well, the beans have been on the shelf in ziplocks (the air mostly squeezed out by hand) since I got them and the oldest have gone through at least 6 seasonal changes, including the heat in my mostly unconditioned apartment over last summer, so that's probably not going to have helped. I get the feeling that I shouldn't be keeping an 18+ month stock... :-/

I actually remember getting some nice flavour out of the Brazilian when it was newly arrived and I didn't do anywhere near such a good job with the roast as this time around (roaster was pretty new to me and I hadn't figured out how to get a probe in yet).

I'll keep hope alive for the new order of greens and thanks for the tips!
 
allenb
Top  #5 Print Post
Posted on 02/26/2017 7:52 AM

Quote

After 4 months, I've noticed a very rapid decline in cup quality


Edit: I shouldn't have stated rapid decline. The rate of decline I've seen is such that within 3 or 4 more months I find enough of a change to where I will usually toss the coffee.

Some HRO members have stated they've gotten good results with extended shelf life just by vacuum sealing (using containers) at a consistent normal room temperature and away from any light sources.

Storing in Mason jars in a consistently cool, dark location seems to gain some shelf life.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
snwcmpr
Top  #6 Print Post
Posted on 02/26/2017 10:12 AM
I vacuum seal into glass mason jars. I do not leave them in plastic bags long at all.
--------------
Backwoods Roaster
"I wish I could taste as well as I wish I could roast."

As Abraham Lincoln said "Do not trust everything you read on the internet".
 
jkoll42
Top  #7 Print Post
Posted on 02/26/2017 11:33 AM
I stopped buying large volumes for the reasons above. The difference per pound for 40# vs 60# for shipping is less than a penny so it's 40#. For me that's under 4 month once I factor in gifts and the few people who purchase some each month.

I like it even better though when my buddy needs beans at the same time as myself and we split a 40# order.
-Jon
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
 
JoseP
Top  #8 Print Post
Posted on 03/07/2017 8:34 PM
OP,

I had a Kaldi for a while. maybe try cutting your finish phase back a bit. I remember getting awesome results with as short as 1min(1C+15F).
 
Ringo
Top  #9 Print Post
Posted on 03/08/2017 8:43 AM
I am going to throw this as something you can try. the quality of my roasts had gotten very flat even bitter. I was roasting 3 1/2 min after first crack because i was told in a roasting class that was good. I went back to my 2 to 2 1/4 min after 1st crack and my coffee is much improved. Brighter with no bitterness. Over the years I was just not tracking like I should.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
DoubleK
Top  #10 Print Post
Posted on 03/09/2017 6:12 PM

Quote

JoseP wrote:

OP,

I had a Kaldi for a while. maybe try cutting your finish phase back a bit. I remember getting awesome results with as short as 1min(1C+15F).


Well, I was going for the Rao% over 20, but I suppose I can easily make it closer to 20 than 30%.

Just to clarify "1C+15F", do you mean 1st crack plus 15 degrees F? Is there a theoretical target you're aiming for here?

Finally, may I ask what you moved to after the Kaldi (or perhaps what you're using now if you've moved on again)?
 
DoubleK
Top  #11 Print Post
Posted on 03/09/2017 6:15 PM

Quote

Ringo wrote:

I am going to throw this as something you can try. the quality of my roasts had gotten very flat even bitter. I was roasting 3 1/2 min after first crack because i was told in a roasting class that was good. I went back to my 2 to 2 1/4 min after 1st crack and my coffee is much improved. Brighter with no bitterness. Over the years I was just not tracking like I should.


I'm wondering if I need to aim for a specific finish temp after FC. Does it matter how close to SC temp (around 220C for me) I get or is it mostly time after FC that matters (without going into negative RoR)?
 
Ringo
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Posted on 03/09/2017 7:29 PM
This is a hard question. Finish temps and time after 1 st crack are two different things. The choice of what temp to stop roast is a balance of the darker roast flavors and the flavors that make that bean special. I think this is personal choice. Not a right or wrong answer. I believe the time after FC is important, and changes with different roasters. What I try to do is have a goal for finish temp, changes with different beans. Then after 1 st crack I try to run a speed that gets me to the goal temp in the 2 min to 2 1/4 min time. If I want a city roast I have to run really slowly for full city I go much faster. My roasting has not been what it should lately so I am trying to relearn this lesson.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
Ringo
Top  #13 Print Post
Posted on 03/10/2017 6:24 AM
I do want to add that I believe 2 min is not long enough for a lot of roasters. Mine just seems to need a shorter development time.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
JoseP
Top  #14 Print Post
Posted on 03/13/2017 7:20 PM
DoubleK,

I meant 15F from the start of first crack(taking about 1-1:30min to get there). I would preheat to 400-415F(medium heat or enough to hover in that temp range)for a 200g charge. Medium high heat to get to yellow(around 320F. I call yellow when I see little to no green)in about 4-5minutes. Adjust heat(or not) to get to first crack in about 3-4minutes(usually around 400F). Adjust heat as needed to give you a 15-20F climb after first crack starts.
My theory was that, with lack of airflow control(not being able to increase it during first crack)would result in smoke taint if I extended finish for too long. I prefer I very light roast with lots of acidity and minimal roast influence so I always drop at the tail end of FC or very shortly after.
I'm roasting on a Quest these days. Honestly, the kaldi was much easier to control. You've got more than enough airflow to get some awesome results, but I didn't feel like there was enough room to experiment with stretching finish time and thermometry was a PITA to rig on the kaldi. I just wanted some more bells and whistles, but I honestly don't think the Quest has improved my roasting as much as experimenting and throwing rule books out the window has...
 
Ringo
Top  #15 Print Post
Posted on 03/14/2017 6:56 AM
Jose
this makes me want to try even a shorter time after 1st crack. Its worth a try to see what it does for me. When I went from 3 min after fc to 2 min it was a big improvement,
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
DoubleK
Top  #16 Print Post
Posted on 03/17/2017 4:20 PM

Quote

JoseP wrote:


My theory was that, with lack of airflow control(not being able to increase it during first crack)would result in smoke taint if I extended finish for too long.


I've heard this a few times before, but it never seems to be a certainty, more like a feeling that something like this would happen when allowing smoke to linger too long near the roasting beans. Is it truth or "truthiness"? Since you mention it was your theory, did you prove it right or wrong?

If it is a quantifiable problem, is there a minimum airflow required to avoid the smoke defect? More specifically for the Kaldi roaster, would the natural airflow be too little to prevent smokiness? I guess I see people roasting in Whirlypops, with no airflow, who don't complain about smoke and wonder how much it can really matter. I thought the main use of airflow was mostly for temp control.

Thanks for all the advice so far!
 
allenb
Top  #17 Print Post
Posted on 03/17/2017 9:32 PM

Quote

I guess I see people roasting in Whirlypops, with no airflow, who don't complain about smoke and wonder how much it can really matter.


I've participated in numerous cupping sessions where we were going between gothot sample roasts (very smoky environment) and Sivetz fluidbed roasts (no smoke). While there were differences between the two roast methods, we never noticed anything that could be attributed to lack of smoke exhaust. In fact, many times, the gothot sample roaster batches were cleaner and brighter than the Sivetz roasts. Anyone claiming they are able to detect a "smoke defect" with roasts done without "optimum" smoke exhaust are either an ultra "super taster" or imagining the defect from suggestion.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
renatoa
Top  #18 Print Post
Posted on 03/18/2017 2:12 AM
The first profiles posted shows a very constant ROR, this is usually the best recipe for a flat taste...
Roasters: DIY: TO based IR 200-640g
Moded commercial: Skywalker, Dieckmann RoestMeister, Nesco, popper(s).
Electrics: TC4ESP, MS6514, USB/Artisan/Apps, PID controllers
Grinders: Arco, Xeoleo ghost burrs, Krinder, vintage PeDe Dienes, MBK Feldgrind
Brew/presso: ALM pour over, Arin lever, Staresso Mirage, Hario Cafeor dripper, Flair, Kompresso, Rota Aeropress, Gaggia Mini
 
DoubleK
Top  #19 Print Post
Posted on 03/18/2017 3:29 PM

Quote

renatoa wrote:

The first profiles posted shows a very constant ROR, this is usually the best recipe for a flat taste...


That's interesting to hear. Can I infer that you're referencing the ever-declining ROR (Rao principles) as the optimum?
 
renatoa
Top  #20 Print Post
Posted on 03/18/2017 3:38 PM
Indeed, isn't this a mantra ? :)
Roasters: DIY: TO based IR 200-640g
Moded commercial: Skywalker, Dieckmann RoestMeister, Nesco, popper(s).
Electrics: TC4ESP, MS6514, USB/Artisan/Apps, PID controllers
Grinders: Arco, Xeoleo ghost burrs, Krinder, vintage PeDe Dienes, MBK Feldgrind
Brew/presso: ALM pour over, Arin lever, Staresso Mirage, Hario Cafeor dripper, Flair, Kompresso, Rota Aeropress, Gaggia Mini
 
JoseP
Top  #21 Print Post
Posted on 03/20/2017 9:04 AM
My pleasure DoubleK!

Well, it's not MY theory. Like you, it's something I've heard a lot and the logic seems sound.That being said, the first handful of roasts were smokey/ashy on my kaldi. They improved once I shortened my finish(or roasted faster in general). Airflow can be used to slow down, increase convection, and remove chaff and smoke(in a closed drum). I think the Kaldi's airflow is just fine, my friend. You just can't control it. The heat control is immediate tho! That's what I miss most about the kaldi.
 
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