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snwcmpr
10/22/2019 5:31 AM
Thanks to you all....... I was not sleeping ... I stayed awake worried about it all. :)

Koffee Kosmo
10/21/2019 5:00 PM
While you were sleeping I have been active in booting out some spammers along with the posts they tried to sneak past me

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Apologies, fixed it asap! BBQ grill

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WOW!! A few minutes ago the site page said "Account Suspended". And would not open the site.

snwcmpr
10/18/2019 2:37 PM
Eth Nat Yirg Idido roasted yesterday. I dropped some off at a friends coffee shop. In a few days he will brew it and tell me what he thinks. We believe my roasts are better than what we buy.

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Santos Acaia graph
groucho
Hello:

I purchased some greens to test, Santos Bourbon Acaia grown at ~1000/1200m ASL.

It is listed as being Arabica size #16 and with Type 2 defects.

I have the feeling that I dropped it a bit too soon, looks a bit light (?).

I tried for a longish drying and early browning stages as I have read that it is the best for this type of beans.

I'd appreciate it if the more experienced roasters in the forum could have a look at my Artisan graph and pitch in.

I've uploaded it, its 600 grams in ~ 10:39 in the gas fired drum roaster I built.

How does it taste?
I think it lacks some body and is a bit acid for 'my' liking.

Thanks in advance.

G.
groucho attached the following image:
sab10_03.png
 
renatoa
DE can't be so high, how are you evaluating the end of green phase ?
 
groucho
Hello:

renatoa wrote:
DE can't be so high, how are you evaluating the end of green phase?

By sight ...
When the yellow is gone from the beans and the chaff is getting brownish ...

I guess I could have clicked on 'DE' earlier ...

TIA

G.
 
renatoa
DE is when beans start to yellow, not when gone.
But this is only a semantic misunderstanding, that, if fixed by moving the actual DE point around 150C, would better balance the green-yellow phases.
Beyond this, though, we have a much serious roasting rule broken, too much heat in the development.
The graph shows an intention to reduce heat, but too late, in the mid of dev.
Next time you should reduce the heat before FC, when reaching 250C, to extend a bit Maillard, and have an average of 5C during the last phase.
 
groucho
Hello:
renatoa wrote:
DE is when beans start to yellow, not when gone.

I see ...

renatoa wrote:
... a semantic misunderstanding, that, if fixed by moving the actual DE point around 150C, would better balance the green-yellow phases.

Like this? (see upload)

renatoa wrote:
Beyond this, though, we have a much serious roasting rule broken, too much heat in the development. The graph shows an intention to reduce heat, but too late, in the mid of dev.

OK. Duly noted.

renatoa wrote:
Next time you should reduce the heat before FC, when reaching 250C, to extend a bit Maillard, and have an average of 5C during the last phase.

I suppose you mean 250° ET ...
The temp I most look at is BT and it seems that there lies my big mistake and why I'm breaking the rule. No?

I usually try to shut down the heat at the very start of the first crack.

But also I find it have difficult or am unable to properly identify start and end up shutting it down when it is a bit further on.

Thanks for your input.

G.
groucho attached the following image:
sab10_03_bis.png
 
renatoa
Yes, 250C ET is where you should hold temp steady until FC, according to Jim Schulmann rule, quoted here:
https://forum.hom...ad_id=5300
 
groucho
Hello:
renatoa wrote:
Yes, 250C ET is where you should hold temp steady until FC ...

Ahh ...
250º C
I was under the (obviously wrong) impression that the ET limit there was around 270/275º C.

renatoa wrote:
... Jim Schulmann rule, quoted here:
https://forum.hom...ad_id=5300

Thanks for the link ...

Cheers,

G.
 
allenb
Groucho,

While we all appreciate Jim Shulmans posting of some industry experts best practices, the so-called rule is not really a rule but is a suggested best practice from his reading of Nestle, Carl Staub and other roasting "experts" in the field. There are no absolutes in coffee roasting and especially when you consider the number of different possible locations we may find to place our ET sensors. Some place them in between the drum and inner sheet metal skin which has no relation to true bean environment temperature. Others place them inside the drum, well away from the influence of the beans hitting them. With fluidbed roasters, the ET sensor may be placed directly above a severe hot spot above a resistive heating element coil where the true average temp is 50+ degrees lower in reality. Take all "rules" with a grain of salt and do your own experimentation to ferrit out the true best practice with your roaster by exhaustive trial and error.

Some of the best roasts I ever cupped were from a large 1 1/2 bag Sivetz fluidbed which ran 570 F ET during the final phases of the roast.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
renatoa
Sure, everything is based on the assumption that roast is mainly driven by hot air, and the air temperature is accurately measured.
But is a lot easier to measure air than beans.

270C is an absolute maximum, where some components of the bean body cellulose start to destroy.
"Severe damage occurs to the cell walls of the matrix at distributed temperatures above 446 degrees F and bean surface temperatures over 536 degrees F The actual temperature values will change due to varying levels of other constituents. Second crack, associated with darker roasts, is the fracturing of this matrix, possibly associated with the volatilization of lignin and other aromatics. Under controlled roasting conditions, the bean environment temperature should never exceed 536 degrees F. A wider safety margin would be achieved by limiting the maximum environment temperature to 520 degrees F. These temperature limits minimize damage to the cell matrix and enhances cup complexity, roasting yield, and product shelf life."
Take the above with the necessary grain of salt, as is coming from Carl Staub, another roasting "expert" :)
In photography we have a saying, you must know the rules, to creatively break them and create art :)

Back to your profile... I think the beans torture begun even during drying... ET of 200C at 1.5 minutes and 250C at 5 minutes marks are too high, imo.
ET probe placement could be an issues, the ET curve starting point is also strange. Why ET start so low and BT so high ?
What machine is this ?
Edited by renatoa on 03/16/2018 9:19 PM
 
groucho
Hello:
allenb wrote:
... especially when you consider the number of different possible locations we may find to place our ET sensors.

Indeed ...

It's been something I have been trying to deal with for the longest while.
With my very first setup using a couple of SS collanders over a gas burner, with my first elementary hand driven drum roaster made from a car's fire extiguisher over butane camping stove with an appliance burner and the DIY gas fired drum I'm using now.

allenb wrote:
... do your own experimentation to ferrit out the true best practice with your roaster by exhaustive trial and error.

Yes ...
An engineer friend of mine once said something that has stayed in my head: you have to *know* your machine. ie. how it behaves under different ciscumstances.

A you can see, I'm still trying. =^)

Thanks for your input.

G.
 
groucho
Hello:
renatoa wrote: ... a lot easier to measure air than beans.

Makes sense to me.
Air is always *all around* the probe, something that is certainly not happening with the needle probe inside the bean mass.

renatoa wrote: ... 270C is an absolute maximum, where some components of the bean body cellulose start to destroy.

I had read the text you are quoting but somehow took 270º C as an acceptable max temp. My roast results evidently say otherwise.

renatoa wrote: ... the beans torture begun even during drying...
ET of 200C at 1.5 minutes and 250C at 5 minutes marks are too high, imo.

I am always taking a look at the BT probe and not the ET which I *know* is not correctly placed (see photo) but used to compare temperatures during the roast with another one placed outside the drum but inside the box. (the one driving the Tenmars TM-712D and wanted to add to the Artisan graph)

renatoa wrote: ET probe placement could be an issues, the ET curve starting point is also strange. Why ET start so low and BT so high ?

I'm sure the problem is with the readings from wrong placements.

BT starts high because the probe is at the far end of the drum and drops when the beans go in.

The ET probe is placed at the mouth of the drum and with the initial internal drum temps (measured at the far end by the BT probe) at drop temperature (below 240º C).

At first it is picking up radiant temperature from the SS exit tube, slowly rising as the roast comes along and hot air starts to move towards the outside by convection, aided by a cowl that sucks up hot air/smoke at the exit but not from inside the drum.

renatoa wrote:What machine is this ?

It's this one. Posted about it here:
https://forum.hom...post_65125

Thanks for your input.

G.
groucho attached the following image:
etprobe.jpg
 
allenb
renatoa posted:
Take the above with the necessary grain of salt, as is coming from Carl Staub, another roasting "expert" :)
In photography we have a saying, you must know the rules, to creatively break them and create art :)


Let me backtrack on my previous post a bit. In general, I'm certain that the results from the experts testing on maximum ET ( air surrounding the beans) was valid and we should strive to design our roasters to be able to achieve a roast without exceeding it or get as close as possible. But, we need to be certain we're getting an accurate bean environment temperature before making unnecessary design changes.

In re-reading the papers from the experts, I will also backtrack on a previous statement where I said the study was only valid with temperatures inside the drum and didn't pertain to fluidbed air temperatures. The study was dealing with air surrounding the bean regardless of how the beans are heated.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
groucho
Hello:
allenb wrote:
... need to be certain we're getting an accurate bean environment temperature ...

Indeed ...
This seems to be the hardest thing to achieve.

I first built my present rig to measure box temperature ie: outside the drum but inside the roaster with an analogue dial thermometer in order to have some sort of reference with respect to what the BT probe was reading inside the drum, at the far end surrounded by the beans moving around. Could not use Artisan with that setup.

I was not satisfied with how this worked so I purchased yet another meter, this time a two channel model compatible with Artisan and set it up as I have it now, replacing the dial thermometer with a probe read by the one channel meter I was using until then to continue to have a reference external to the drum.

I have the idea that for a given roaster (combination of size, weight, materials used, energy input, air circulation, etc.) there will always be a perfectly traceable correlation between any set of readings (obviously using more than one source) taken within the system.

But I am not too sure that two "identical" roasters will behave in exactly the same manner, meaning that even using the exact same probe locations the correlation between the set of readings will not necessarily be the same in both.

In any case, I think that the trick at hand is how to use that set of readings.

Thanks for your input.

G.
 
allenb
You're welcome!

Something else to consider with drum roasters: Depending on the amount of air flow being pulled through the drum and the degree of heat transfer between the drum heat source and the air being pulled across it, one can have an acceptable ET inside the drum and at the same time have too much heat being transferred from drum wall to beans causing scorching, tipping or other heat related damage to the bean's structure.

Obviously, in your case, with natural convection through a Jabez sample style roaster (very nice looking roaster I might add!) the flow is set by how much upward convection lift there is. This being the case, you should never have a problem with excessive convection causing an abnormally low internal drum ET.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
groucho
Hello:
allenb wrote:... one can have an acceptable ET inside the drum and at the same time have too much heat being transferred from drum wall to beans ...

At the time I was sketching my blueprints (on a napkin type freehand sketches) there was a lot of discussion in various sites wrt the vanes inside the drum: number, size, placement, parallel to the drum axis or not, etc. all of which in whatever combination and coupled to drum speed, were supposed to avoid scorching/tipping during the roast.

I finally gave up and just slapped in three vanes parallel to the drum axis and with a height that was a bit over 15% of the drum's diameter and hoped for the best.

Having done that, the reasoning behind taking temperature readings inside the box / outside the drum and relying on my assumption of a reasonably stable correlation between both temperatures once the system was stable gained more weight (at least for me).

allenb wrote: ... with natural convection through a Jabez sample style roaster (very nice looking roaster I might add!) ...

Thank you. =-)

allenb wrote:
... the flow is set by how much upward convection lift there is.

Yes, and I expect that it is also linked (but not too much) to the differential between ambient and inner drum temperature.

Once I made the cowl to get rid of the smoke that filled my appartment (!) each time I roasted and found the right placing for it, I found that it could influence, albeit minimally, the trace of the ET curve.

It is made from 3" galvanized heating pipe using a good quality fan from a server's power supply also running on battery power and placed half way inside the length of the pipe so as to protect it from excessive heat. On the to-do list is hooking up a speed regulator for the fan.

allenb wrote:
... should never have a problem with excessive convection causing an abnormally low internal drum ET.

I have not had that happen. I dread stalling a roast, which is why I added another pair of burners with a heat shield to the original build. (see photos)

Having seen the graph, would you say that charging at 220º C is too high?

Thanks in advance,

G.
groucho attached the following images:
det_6_1.jpg 4_burners.jpg

Edited by groucho on 03/17/2018 10:08 AM
 
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