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allenb
OfflineAdmin
· 04/02/2020 4:50 AM
Morning Ed, I haven't done any green coffee hoarding yet but am hoping the supplies don't end up like the toilet paper isles!

snwcmpr
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· 03/31/2020 2:53 PM
Hey Ed. Thanks. roar

homeroaster
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· 03/31/2020 11:21 AM
Hey quarantined home roasters! I hope you have great coffee! If they have a run on coffee, I hope you're set with your great home roast! Find me on Facebook! Ed Needham

snwcmpr
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· 03/25/2020 11:49 AM
New Rochelle in the news. I think of you every time I hear it. ... Please stay safe.

allenb
OfflineAdmin
· 03/21/2020 7:36 AM
Good morning homeroasters morning Everyone is hopefully staying healthy through this. Hang in there and stay safe!

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optimum temperatures for roasting
troposcuba
oops. I meant water boils at 206* (not 106*) at my house. too late to go back and edit.
Sean
 
yamhill
Would it be better to talk about barometric pressure instead of altitude? Seems like the first crack temperature would be a factor of barometric pressure, bean temperature, bean moisture (think of moisture in the sense of all compounds that expand or would go to gaseous state in the roast temperature range), and the strength of the bean. To measure the impact of one of these, you would be faced with the need to hold the rest of the variables constant - which would be a non-trivial task.

First crack temperature (as measured by a probe in the bean mass) can move around a little with different roast profiles too.

John
 
John Despres
Here's a link to the entire discussion Ciel mentioned:

http://forums.roastersguild.org/viewt...5&t=87

I think the experiment mentioned in the Roasters Guild forum is the same article member hazbean posted - http://e-collection.library.ethz.ch/v.../eth:23461 - (Page 45 in the pdf and page 33 of the document itself.)

If there's another experiment with embedded bean probes, I haven't seen it. I've looked but cannot find one.

It's all interesting, though.

John
Edited by John Despres on 07/17/2012 7:46 PM
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
www.sceneitallproductions.com
ginny
simagic:

looks like you have created a temp/time thread in the Gene Cafe forum.

thanks,

ginny

cool
 
yantacaw

Quote

ciel-007 wrote:

Hi Simagic, and welcome to HRO.

With the GC, you will find that there’s no direct, simple answer to your question. In my experience, it was largely a matter of trial and error before arriving at the optimal roasting settings. You will first need to test your GC to see how quickly it reaches 482F. Although rare, some GCs are very very fast, and may even lead to scorching as discussed in this thread:
http://homeroasters.org/php/forum/vie...ad_id=2744
The main challenge you face with the GC is that there is no way of knowing the actual temperature of the bean mass during roasting. You will have to learn to judge the BM temperature using other clues like smell, smoke and bean color.


hi ciel, i have not previously seen the inconsistencies with 1st and 2nd crck times that you have on the sm site but to be sure, i believe it's possible.

can i ask you how you have a thermocouple successfully attached to you gene? i've tought of doing this as but assumed the off axis rotation would pose some problem for a thermocouple or bean probe.

sigimac, are you using a kill-a-watt? i can't justify them for most things in the house as some might but it has been essential for me with roasting as power availability varies in our home - especially during these intensive months.
 
yantacaw

Quote

ginny wrote:

simagic:

looks like you have created a temp/time thread in the Gene Cafe forum.

thanks,

ginny

cool


i , for one, am glad for that. when i first started roasting a few years ago, i didn't trust my senses or my judgment and tried to be as precise as possible. i pored over everything i could get my hands on. seeing the large range of approaches didn't help me either. difference, its been said, doesn't differentiate. after an extended period of roasting with one eye on the machine and one on a range of -yes, contradictory-guides, i eventually started to just roast on feel. this has been important for me - not as someone who needs to get exact results every time - but for someone who wants to enjoy the process of making roasted coffee and it was and still is an especially important process for depending on your own faculties - smell, sight , sound (on the subject of sound, has anyone tried using one of those mechanics stethoscopes?, or contacts?). alas, this creates a certain comfort and very basic self confidence which is so important - at least for me - to the process. i guess i would say that i am the same with baking bread - somewhere between the spirit and science of process, leaning on spirit. that being said, i know in spite of my happiness and successes with home roasting, every now and then i have had some shocking foul ups many years later and now wish to revisit some of the techniques available to get more precise. i've just grabbed a few affordable used american made variacs for my roasters and believe this will allow some room for greater precision as well as continued experimentation. refine or plateau, i say!

simagic, thanks for posing the question
ciel, thanks for questioning assumed knowledge
john, thanks for having the energy, experience and willingness to revise your own assumptions
ginny, thanks for facilitating the forums!

p.s., i've forgotten what the general disparity is thought to be between the temp read out on the gene and actual temp of the roasting 'drum' is?
thanks!
 
John Despres
Hi, yantacaw.

With just about every new article or post I read, I often feel like I'm starting over. I'll never stop learning and our members all have much to share.

If 1st really occurs somewhere between 380 and 400F, my Gene Cafe may show 465F (which is drum temp), the difference is about off about 65-85F.

However, I can set the GC at 440 and still hit 1st crack, so the difference doesn't mean much, really.

Since this discussion started, I've noticed I don't really pay much attention to the relative temp until 1st occurs. Interesting. Time and reaction are more important, perhaps.

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
www.sceneitallproductions.com
simagic
I'm sorry if this is duplicated. i can't seem to find my thread, so I'm posting it again. moderator.please delete if duplicated.


Simagic here....... I've learned much by reading the replies to this thread. One thing I do believe ( and someone correct if I'm wrong) is that it doesn't matter if my starting temperature is 470 or 482 or 900. if i'm going to turn it down after the first crack, then it doesn't matter how high the temp is set to. I was reading somewhere "here" where someone said they set it for 482. Someone responded that it was too high of a starting temp... link.. http://homeroaste...ad_id=2744 . I believe it doesn't matter if I set it to 2500 degrees as long as i bring it down to 445-465 when it reaches first crack. kinda like turning the shower hot water up to high while you're preparing to get in, but just when you get in you turn it down to the correct temp. Am I wrong
 
ginny
your post is the very FIRST POST in this thread, you will note that at the top/bottom of each thread page there are numbers, page 1, 2, 3 etc, you need to go back to page one and to the top and you will see you started the thread.

perhaps you are confused because there is an award icon at the top of your thread, you were given a post of the week award.

you can also look down under and thread and see your recent posts and click on them.

you only had one post, it started this thread, gotta look back, gotta look around period and understand how the forum works, check the buttons, push a few you cannot hurt yourself or the forum but you will learn a lot...

ginny

party
Edited by ginny on 07/18/2012 9:22 AM
 
John Despres
Yes, it matters. The higher you set your heat at the onset, the faster your beans will roast.

Try this - roast two matching batches.

Batch one. Set the high heat at 445F
Batch two. Set the high heat at 482F

Allow the roaster to totally cool between your test roasts and start over as in batch one. It doesn't matter if you preheat or run a warming stage.

Which reached 1st crack sooner? Which tastes better?

This exercise merely shows you can get the beans to 1st under almost any drum temp as long as the drum temp is above that at which 1st occurs between 380 and 401F (still under discussion). Somewhere here I posted about setting the GC at about 425F and still reached first crack, but it took about 25 minutes and the brew tasted flat and dull. Kinda like Sanka.

Another consideration and perhaps the most important is your bean type. Softer, low grown beans need a very gentle heat at the onset and throughout the roast - Under 1500 meters altitude. Mid altitude, 1500 - 4000 meters require moderate heat at the onset. High altitude beans need high heat at the onset. SHG and SHB beans love heat! Pour it on!

Higher heat roasts are more difficult to slow down toward the end of the roast and will require practice.

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
www.sceneitallproductions.com
simagic
So, what I hear you saying is that if I set it to 482 it will reach 465 faster than if i set it to 470. I'm not arguing, but my logic tells me that the temp will climb at the same rate up to 465 no matter what the peak temp is set at as long as it's higher than 465 . In other words the heater will continue to 'heat' until it reaches its cut off point ( when you decide to lower it) which in this example is 465 at which time you choose to lower the temp ( if you've reached 1c) . My belief ( via logic) tells me that the heater doesn't put out any more heat while climbing to 470 or 482, therefore it wouldn't reach first crack any sooner by setting temp at 482. It just stays on longer if set to 482. Therefore, if you are going to turn it down at 465 ( just as an example), it's going to climb to 465 at the same rate no matter if you have it set to 470 or 482. When you set the thermostat in your house to 75 degrees, your heater stays on til 75 (plus a bit more), and then shuts off. It stays on till 75. If i set my thermostat to 80 , it doesn't put out a higher temp or get hotter any faster , it just stays on longer til it reaches 80
 
John Despres
These are excellent questions!

You are correct in noting in either or any setting, the drum will reach 465F in about the same time, every time.

However, you will reach first crack sooner with the higher temp setting. Depending on where you set your high temp is what determines the speed to first crack.

Assuming a hard bean roast now:

On my GC, if I set my high at, say 465F, the drum will reach 465F and stay there for a bit before the beans reach first crack, maybe 30-45 seconds. The lag between reaching 465F and first crack is the important factor, here. This will happen while the drum temp swings as low as 458F and back up to 465F. The drum temp is cycling a bit cooler and back up to the high setting. With this in mind, the beans cannot logically be heating as fast as they would if the temp were set at 482F and continually rising.

The marker is first crack, not the numbers on the read out.

Some may ask "Is this stalling the roast, then?" The answer is no. Stalling is letting the actual bean temp drop, not necessarily the drum temp.

We know roughly (very roughly, still open discussion on this) where 1st crack occurs and as long as the drum temp remains above that window of reaction, the beans will continue to rise in temperature.

If the drum temp is cycling between 458F and 465F, and 1st has not occurred, you are not stalling the roast.

The only real guides we have are being able to see, hear and smell our Gene Cafe roasts.

If you want a nice city plus roast, and are aware of what the perceived temp parameter of first crack is, you need to keep your drum temp at or slightly above those perceived temps. Dropping to as low as, say, 390F may very well stall the roast and the bean temp will probably drop. Dropping to 445F will slow the roast without stalling it. Dropping to 425F will slow it even more and you run a lesser risk of hitting second crack.

Have fun!

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
www.sceneitallproductions.com
yantacaw

Quote

John Despres wrote:

Another consideration and perhaps the most important is your bean type. Softer, low grown beans need a very gentle heat at the onset and throughout the roast - Under 1500 meters altitude. Mid altitude, 1500 - 4000 meters require moderate heat at the onset. High altitude beans need high heat at the onset. SHG and SHB beans love heat! Pour it on!

Higher heat roasts are more difficult to slow down toward the end of the roast and will require practice.

John


hey john, wouldn't you also want to give some consideration to volume? it stands to reason that more beans will ultimately heat up faster than fewer beans (i don't necessarily mean more evenly or with better results). i recall finding a forum - australian maybe - where this was discussed at length with regards to the gene cafe and flew in the face of the maker's own recommendations.
 
yantacaw

Quote

John Despres wrote:

Hi, yantacaw.

With just about every new article or post I read, I often feel like I'm starting over. I'll never stop learning and our members all have much to share.

If 1st really occurs somewhere between 380 and 400F, my Gene Cafe may show 465F (which is drum temp), the difference is about off about 65-85F.

However, I can set the GC at 440 and still hit 1st crack, so the difference doesn't mean much, really.

Since this discussion started, I've noticed I don't really pay much attention to the relative temp until 1st occurs. Interesting. Time and reaction are more important, perhaps.

John


john, i hope this doesn't swing things off topic but since the thread has a 'how things work' vibe to it, let me ask you what you're roast approach is these days.
i believe the last time i was on the boards - ages ago - you had been practicing the straight heat to first method (a la sweet marias) but had previously been playing around with alternatives such as slower ramp ups and what not. if i remember right, you had ultimately bagged the 'experimental' ramp up as the so-called drying time seemed perhaps less necessary for home roasters who were subject to relatively long lead times to get to first crack anyway when compared with 'professional' roasters using industrial equipment (i readily acknowledge i may be talking out of my hat here). what are you doing these days or do you continue to 'search'?
 
John Despres

Quote

yantacaw wrote:

hey john, wouldn't you also want to give some consideration to volume? it stands to reason that more beans will ultimately heat up faster than fewer beans (i don't necessarily mean more evenly or with better results). i recall finding a forum - australian maybe - where this was discussed at length with regards to the gene cafe and flew in the face of the maker's own recommendations.


You're correct, but there isn't much room for varying volume in a Gene Cafe. I recommend the same amount every time. I roast 226 grams each roast (half pound) and eliminate that variable. I know some folk who change it, but in the continuing learning curve, eliminating one change is a step toward better understanding.

Another reason for a half pound is my per pound order gets divided evenly and I don't have an odd size batch at the end. Some folk roast as much as 300 grams. At 226 grams I don't have many chaff problems, either.

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
www.sceneitallproductions.com
simagic
How do you give low grown beans "gentle heat" from 0 to 465 and Hi grown beans "higher heat" from 0 to 465. I'm preheating for drum for 5 min. Then warming beans for 5 min and then turning it up to 465 until 1c. How do you change gentle heat to hi heat in that scenario
 
John Despres

Quote

yantacaw wrote:

john, i hope this doesn't swing things off topic but since the thread has a 'how things work' vibe to it, let me ask you what you're roast approach is these days.
i believe the last time i was on the boards - ages ago - you had been practicing the straight heat to first method (a la sweet marias) but had previously been playing around with alternatives such as slower ramp ups and what not. if i remember right, you had ultimately bagged the 'experimental' ramp up as the so-called drying time seemed perhaps less necessary for home roasters who were subject to relatively long lead times to get to first crack anyway when compared with 'professional' roasters using industrial equipment (i readily acknowledge i may be talking out of my hat here). what are you doing these days or do you continue to 'search'?


Since you asked -

Oh, I still play. I recently saw something in a Sweet Maria's blog about something or other and played with a new profile that doesn't seem to work well for me and the the Gene Cafe - I over roasted 3 batches of a nice Ethiopia Harrar. Makes a pretty nice espresso, though, so it wasn't a total waste.

At the moment, I'm playing with a 5 minute warming period, then a rather low setting for my high between 445F and 460F allowing me to cruise into first a bit slower, then dropping to 435F and even lower within the first 30 seconds of the onset of first. Interestingly, this has set me up for greater risk of second crack, it seems. I'm not sure why, but it could be because I'm getting more heat through the entire bean right to the center and creating a better chance for a faster exothermic reaction. First comes a bit later but it still comes between 12 and 13 minutes.

The coffee has been quite good but I'm sure I'm not doing something revolutionary. I just like to play. If I totally ruin a batch (rarely), I don't do that again, but I think I learn something each time.

Some time ago I even added a squirrel cage fan to force more air into the GC and tried controlling heat that way while leaving the heat settings alone. I did that for about 100 batches and while I didn't ruin any coffee, I stopped because it didn't seem to improve things much, but rather complicated the process with no great results. I think it didn't work very well because I was still moving air across the heating element.

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
www.sceneitallproductions.com
John Despres

Quote

simagic wrote:

How do you give low grown beans "gentle heat" from 0 to 465 and Hi grown beans "higher heat" from 0 to 465. I'm preheating for drum for 5 min. Then warming beans for 5 min and then turning it up to 465 until 1c. How do you change gentle heat to hi heat in that scenario


Gentle heat - lower setting for your high. 450F or 455F, lower if you like.
Higher heat - higher setting for your high. 465F or 470F, higher if you like.

In either case, the rate of rise will be the same until the set temperature is reached, then with the cycling up and down, the heat is applied a little slower and more gently or is still poured on as the climb continues to the higher set temp.

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
www.sceneitallproductions.com
simagic
Back to temperatures on the GENE. I would have to guess (and certainly may be wrong), that most people reading the threads in the Gene cafe forum, do not have some sort of temperature reading device "somehow" connected to and reading the "internal temp" of the beans. We all, (except those few), are strictly relying on the machines readout for the temp. This means ""TO ME"", that when I read info as to the "internal temp" of the beans, that I just have to skip right past it as there is no way for me to have any idea what the internal temp is, on the GC. There is no relationship (as I see it) that I personally can make between the internal temp of the beans and the readout on the machine ( of which we are totally reliable upon for our temp info). ANNND, in additition ( if I may), some threads speak about very exact "times" for 1c/2c or etc. Well, that's the times for 'their" machine. I would think, by reading many of these threads, that not everyones machine heats up at the same exact time. Therefore 11 minutes and 45 seconds (for an arbitrary figure) on one persons machine is meaningless to another. I would think that i would get the best info by hearing at what "TEMPS' the "machine" was reading out at 1c/2c or etc ( for an equal amount of green coffee) ( 8oz. for an example). I know that there would be many variables for coffee type/altitude/ hard or soft bean/ etc. But, at least it would be something to be able to relate to, as we all (owners of the GC) have the digital readout to look at....Or maybe I'm wrong?????
 
ciel-007

Quote

yantacaw wrote:

hi ciel, i have not previously seen the inconsistencies with 1st and 2nd crck times that you have on the sm site but to be sure, i believe it's possible.
can i ask you how you have a thermocouple successfully attached to you gene? i've tought of doing this as but assumed the off axis rotation would pose some problem for a thermocouple or bean probe.



I apologize for not replying earlier; I had not noticed your question until re-reading through this tread today.
I believe you are correct; I do not know of anyone who has yet been successful in placing a thermocouple inside a GC. I roasted for several months with the GC, before deciding to buy a second roaster that allowed me to install a thermocouple to probe the evolving bean mass temperature during roasting.
If feel that the presence of a thermocouple in a roaster allows one to introduce a bit more science into the art of roasting.
Ciel... seeking Heaven in my cup with ................................................................................................................. EXPOBAR Brewtus II - MAZZER Mini E - MAHLK�NIG Vario - GeneCafe - RAF-1 Extreme (Modified B-2 HOTTOP) - BellaTaiwan XJ-101
 
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