Green Coffee Buying Club
Coffee Discussion boards => Hardware & Equipment => Topic started by: H-D Rider on December 10, 2009, 07:37:07 PM
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OK since I got my Ambex YM-2 I have been struggling to get good roasts. I know there is a learning curve and I don't expect to become a Roast God overnight but I'm sitting here at work tonight with a fresh cup of Ethiopian Hope Project, roasted 72 hrs ago and it's better than the local fuel stop swill but I have no fruit. Many of my roasts since I got the Ambex are good tasting but not what I was getting from my Hottop. I know it's my fault but I'm ruining good beans. They're a good drinkable beverage but not at all what they should be. I've tried #3 roasts down to 1# roasts. I have times that I would think are very respectable as far as time to 300 and yellow, time to 1st and a nice coast (3-4 min) to end of roast, but they aren't really successful in taste quality.
Here's what I have done in general. Drop temps vary with size but my attempt is to bottom out in 45 sec-1min. Recover to drop temp in another minute. Steady rate of climb to 300 within 5 min. 4-5 min to 1C. coast to end of roast 3-4 min. Lighter roasts(just out of 1c 3-3 1/5 min) Darker roasts just this side or very slightly into 2c, 4 min. Roasts are normally 12 to 14 1/2 min total and consistant with batch size. I've been able to get the #3 roasts to profile very similar to a #1 batch but obviously my profile is not working and I'm stuck.
I'm at work and don't have my temp records with me to post right now. I leave the air on full throughout. I read somewhere that was Ambex's technique. Perhaps that's where I need to adjust.
I was hoping one of you old experienced Ambex users might shed some light and keep me from squandering away any more good beans as mediocre coffee. Just a generic profile perhaps or a normal rate of climb between the phases? Air adjustment maybe?
If not I'll have to start my Christmas roasting way earlier than planned 'cause the Hottop only does about 1/2lb batch.
Thanks Guys/Gals
HD
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I can only wish I had an Ambex.
Your ramp from 300 to 1C does not allow enough time in the 350F range to caramelize the sugars and develop sweetness that the fruits need. I always let my roast hover in the 350-360 range for a few minutes.
That's my shot in the dark.
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HD--what's your temperature reading at the equilibrium point? (bottom out). I trained a bit on a YM-2 with the roaster who worked with Ambex to develop their automated profile tool. She recommended that your equilibrium point not be above 150°F. We tested this with the Alta Mogiana Brazil, and there was a BIG difference between above and below ~ 150°F. The higher equilibrium temp gave an ashy taste to the beans.
Ambex does not recommend modifying the air profile within roasts, but I don't recall if the recommendation was full air or slightly off that. Your times are not far off what we found successful with that Brazil, but we didn't do much profiling with other beans in that class, and I'm sad to say I have no YM-2 here.
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I've found that 3# or more produces the best results. A couple of questions
1) what is your drop temp for 3#
2) what are you roasting (high altitude grown beans roast differently) Ethiopians are pretty high grown normally.
3) Time from bottom temp to 300
4) Time from 300 to 1st crack
5) time from 1st to 2nd
I'm fairly new to the Ambex too but have had some pretty good roasts out of it.. similar or better than the hottop.
If you are missing the fruit Peter is right. You may be getting to 1st crack too soon. Remember that stage is where the water evaporates out of the bean and if you get there too soon the water in the center of the bean doesn't get out. I've been dropping at 300 with 3# and bottom out at 145 or so, then back to 300 in about 5 minutes and hover there for a bit then on to 1st crack in about 10 minutes hovering at 350 for a bit then off I go to second crack in 3 minutes after 1st has stopped.
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I've never used an ambex, so I'm pretty useless here as far a specific temps. But for a lot of DP's I like to reduce the heat a minute or so before first crack. Then I shoot for three minutes between cracks. Depending on what darkness I'm going for, I'd drop it right before second crack or right at second crack, or possibly ten or fifteen seconds in.
I like to pull beans during the late stages and observe them, and even taste them. I notice the fruitiness can go away pretty fast if you wait too long. And there is also a body consideration of course.
I think a lot of it is trial and error. That's why beans come in such big bags! ;D I rarely roast less than 15 pounds, so I try to figure it out as quickly as possible..
Cheers...and happy roasting! Keep us posted on your results.
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........ That's why beans come in such big bags! ;D
I've always wondered why.... makes sense now! ;D
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I can only wish I had an Ambex.
Your ramp from 300 to 1C does not allow enough time in the 350F range to caramelize the sugars and develop sweetness that the fruits need. I always let my roast hover in the 350-360 range for a few minutes.
That's my shot in the dark.
Peter, for you, is the 350-360 range right before the first crack usually?
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I can only wish I had an Ambex.
Your ramp from 300 to 1C does not allow enough time in the 350F range to caramelize the sugars and develop sweetness that the fruits need. I always let my roast hover in the 350-360 range for a few minutes.
That's my shot in the dark.
Peter, for you, is the 350-360 range right before the first crack usually?
No sir, 1st varies, but is generally beginning ~400, lasting 'til ~415-420. 2nd crack is generally beginning ~430 in my setup, a SC/TO.
Speaking of a pro-roaster, this is the time of year I wish I had one; I roasted 7 hours yesterday, netting 30#. Today's the same gig. :-\
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On my USRC 18K machine - 1st crack starts around 340-350 on smaller batches, and 360-370 when fully loaded.
2c will start right around 395-410 depending on batch size.
-Stubbie
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Speaking of a pro-roaster, this is the time of year I wish I had one; I roasted 7 hours yesterday, netting 30#. Today's the same gig. :-\
You could almost had flown here, roasted your 30 lbs and flown home.. 8)
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On my USRC 18K machine - 1st crack starts around 340-350 on smaller batches, and 360-370 when fully loaded.
2c will start right around 395-410 depending on batch size.
-Stubbie
Why is that? My Ambex is close to those #'s and for the life of me I can't figure out why other than my thermocouple must not be accurately measuring bean temperature...
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On my USRC 18K machine - 1st crack starts around 340-350 on smaller batches, and 360-370 when fully loaded.
2c will start right around 395-410 depending on batch size.
-Stubbie
Why is that? My Ambex is close to those #'s and for the life of me I can't figure out why other than my thermocouple must not be accurately measuring bean temperature...
Why the differentiation in temps on crack times?
I have always assumed it was due the amount of thermal mass inside the drum.
On airflow, I usually go low (10-25%) at the beginning, 50% 5-6 mins in, 75% at the onset of 1c and 100% during the ramp up to 2c, with the burners turned back down low.
-Stubbie
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On my USRC 18K machine - 1st crack starts around 340-350 on smaller batches, and 360-370 when fully loaded.
2c will start right around 395-410 depending on batch size.
-Stubbie
Why is that? My Ambex is close to those #'s and for the life of me I can't figure out why other than my thermocouple must not be accurately measuring bean temperature...
Why the differentiation in temps on crack times?
I have always assumed it was due the amount of thermal mass inside the drum.
On airflow, I usually go low (10-25%) at the beginning, 50% 5-6 mins in, 75% at the onset of 1c and 100% during the ramp up to 2c, with the burners turned back down low.
-Stubbie
I think Larry was asking about the low temps for the two cracks. If he wasn't, I am. It seems odd that 1C would be starting around 340-350.
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That low of temps is on 5-6# batches as compared to 30-35# fully loaded.
Each bean is different too, as are therm probes and their locations I'm sure. Mine is located right below the sight glass on the left middle side of the drum.
When I fire up the machine, the temp always reads accurately to the temp in the room.
-Stubbie
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My USRC 5-kilo is in the range of Stubbie's, maybe a bit higher. First is usually 345-370 and second starts around 410-420. From my understanding, the main difference is thermal couple placement.
Peter, generally speaking on a timeline, what's your total roast time? Time fo 350-360? Time at first & second crack? Time that your second crack ends? ;)
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My USRC 5-kilo is in the range of Stubbie's, maybe a bit higher. First is usually 345-370 and second starts around 410-420. From my understanding, the main difference is thermal couple placement.
Peter, generally speaking on a timeline, what's your total roast time? Time fo 350-360? Time at first & second crack? Time that your second crack ends? ;)
These are rough estimates, mind you... I simply have a basic profile that almost everything gets.
2.5min. to 300, sits there for 3min. to dry;
2.5min. to get to 350F, sits there for 3min. for sugar caramelization;
2.5min. to beginning of 1st, a couple minutes of slowly increasing temps.;
2min. or so after 1st for flavor development, by then it's a few vanguards of 2nd.
That puts me around 16min. for a C+ ~ FC, maybe 19 for a light Vienna.
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Thanks for the responses and I've already got some good ideas.
Chad, I was told the 150 equilibrium temp was what I should shoot for and the roast below I was trying for that. It seemed low so my subsequent roasts were more in the 185-200 range. Back to the 150 mark I guess.
I've found that 3# or more produces the best results. A couple of questions
1) what is your drop temp for 3#
2) what are you roasting (high altitude grown beans roast differently) Ethiopians are pretty high grown normally.
3) Time from bottom temp to 300
4) Time from 300 to 1st crack
5) time from 1st to 2nd
I'm fairly new to the Ambex too but have had some pretty good roasts out of it.. similar or better than the hottop.
If you are missing the fruit Peter is right. You may be getting to 1st crack too soon. Remember that stage is where the water evaporates out of the bean and if you get there too soon the water in the center of the bean doesn't get out. I've been dropping at 300 with 3# and bottom out at 145 or so, then back to 300 in about 5 minutes and hover there for a bit then on to 1st crack in about 10 minutes hovering at 350 for a bit then off I go to second crack in 3 minutes after 1st has stopped.
Charge temp was 280
Used Stubbies Brazilian
Bottomed out at 147 in 50 seconds
300 at 7 minutes from Charge
5 1/2 minutes from 300 to 1c at 384
2 minutes from end of 1c to first snaps of 2c and ended roast then at 408 degrees
Looked nice, even FC/FC+ by my guess. Taste was flat.
On my Ethiopian I have only tried #1 roasts. So the numbers are different, but still similar except faster from 300 to 1st. I guess that needs to be lengthened out a bit and back to the 150 Charge temp.
Other Ideas or instructions?
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How long are you running full flame before 300F? With the Brazil profiling we did, we'd set it up so the computer profiler would start controlling about 220F, with a bit faster time to 385F (~9-9:30 for a 2.5-3# roast).
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You should give Terry Davis a call or drop him an email. http://www.ambexroasters.com/index.html. (http://www.ambexroasters.com/index.html.) I'm sure they could give you professional advise to help you get the most out of your roaster.
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Wanted to add this forum as a reference source for information. The unoffical Ambex roaster forum http://billgiffen.com/ambex/index.php?sid=d0eafb6ca8aa23c896b0371615e0f93e (http://billgiffen.com/ambex/index.php?sid=d0eafb6ca8aa23c896b0371615e0f93e)
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How long are you running full flame before 300F? With the Brazil profiling we did, we'd set it up so the computer profiler would start controlling about 220F, with a bit faster time to 385F (~9-9:30 for a 2.5-3# roast).
Chad
I have propane. Full pressure is 10. I ran full flame from drop to 240, about 4 minutes. Then cut to 8 till 300 about 7 minute mark. Full to just before 1c( about 10 seconds before ) then cut to 6. still rising too fast(I thought) cut flame to 3 at 397 about the 14 minute mark. Ended at 15:30 @ 408.
Are you saying your profiles were about 9-9:30 to 385 from charge? If so mine was about 4 minutes behind yours. Mine was 13:30 to first crack, which was at 384 on my machine with this bean. I have found this one hits first with a small load anywhere fron 350-365 and with a 3-4# anywhere from 375-385. Caught me by surprise at first because the hottop was pretty regular at 397-401.
H-D
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I am a want to be Amebex user but I found this. It will be a help too me someday. http://www.ambexroasters.com/pages/articles/article/managing_profiles.html (http://www.ambexroasters.com/pages/articles/article/managing_profiles.html)
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I ran a YM2 3-6 days a week for about a year and now run a YM10 about 3-5 days a week. I figure another 10 years or so and I might actually know what I am doing! As for bringing out the fruits, etc, I have to agree with Peter that you might want to stretch that pre-1st crack time out to better develop what you are looking for. That said, I am having the same problem with a Harrar that I have: very nice chocolate notes, but the fruit is quite muted and only pops as it cools. Had the same problem with it on my Hottop though. To counter that, I have a Guat Huehue from Coffee Holding that has some pretty powerful citrus/blueberry and it comes out very easily as long as I stop short or just at 2nd crack.
I did the Ambex training a few years ago and they did indeed promote a 150 degree equilibrium point. They also promoted a "leave the airflow alone" position, using full air. I back mine off slightly as my machine gets quite hot and it helps prevent chaff fires (although I found a new fix for that). Kathy Z from Coffee Holding Co was a big part of my training session and she was very helpful. She has experimented a lot with the Ambex machine and can be quite helpful. What I am about to say next is subject to personal opinion. I am not saying it is true or false, just what was promoted. In my seminar they suggested that the time to first crack was much more important than the time between first and second. They promoted a 13 minute to first time frame. Seems a little long doesn't it?
As for the comparisons of 1st and 2nd crack times, I have a few observations on my machine. First crack for me comes between 360 - 380, depending on the coffee and the time of year (yes, the time of year!). I have seen a big difference in the nature of my roasting in the spring/summer and fall/winter. Second crack on my machine usually comes between 424 - 432, depending on the coffee. Even though Ambex said it makes little difference, I have found the most challenge in stretching out 1st to 2nd times. One of the reasons is that I almost always roast full batches (15lbs for me) and it sometimes seems I do not have enough power to meet the criteria I want, forcing me to run full-tilt for the entire roast. This is typical for the first few roasts until I get the machine warmed up more. I counteract this by roasting smaller batches for the first few roasts. I am able to run a 4.5 - 5 pound batch on my machine no problem.
Shep
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shep,
Kathi Z taught my roasting profiling class, and she was working for/with Ambex when they developed their automated profiling system--she did the roasting and cupping, and worked with the programmers/engineers to get the profile system working. A wealth of knowledge, and, in her new capacity, a good source of coffee.
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Any YM-2 users out there have the version of the machine that has the electronic gas valve. Instead of the manual/automatic switch it has a rotary knob.
If you do can you look and see what the make and model # of that valve is? I want to replace my on/off valve with the electronic valve.
thanks
Milowebailey
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I'll check mine in the morning, that's what I've got.....................Milowidget in development, perhaps?????
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.Milowidget in development, perhaps?????
;D.... maybe...... ;D
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Larry
The only number I could find on the Honeywell Valve was SV9501. The valve is ahead of the control unit which is a Maxtrol M420RH. Hope that helps.
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Larry,
I'm getting another independent check from a roaster friend of mine as well. It is a honewell, I know that. Part # to follow.
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I just did a google search on the SV9501 and the pic is exactly the same as mine. $130-190
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Larry
The only number I could find on the Honeywell Valve was SV9501. The valve is ahead of the control unit which is a Maxtrol M420RH. Hope that helps.
Could you snap a photo or two for me too?
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Does this show what you need?
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Yes I believe it does...
Thank you!!!
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I have a question for the drum heads. I built my roaster, big steel drum, propain powered. I have three termocouples installed. #1 Is in the beans as they roast #2 is at 12 oclock on the drum for environmental temp #3 is in the hot gas stream just before it is pulled through the drum. The relationship between the three temps is based on the air flow. Very high air flow through the drum Bt is the highest, I think this is becouse I am heating the big steel drum up too much and the radient heat is in charge, coffee roasted this way is flat. So I started turning back the air alot as I roast, flame set to med high. This is a better flavor but I think it shoud be better. With very low air in the drum at 1c Bt will be 375, Et will be 380 , Firebox temp will be 430.
Now the question- Does this firebox temp seem too high? With an ET at 380 and a FB temp of 430 I would think I am heating the drum up too much? Coffee roasted this way is not bad, but I think it has room for improvment. I will hit 300 deg around 5:30 min, 1c around 9 min, end the roast around 12:30 Bt around 390 for a City+ roast.
Question #2 I am really having a hard time getting a handle on drop temps, Every time I drop the turnaround is different. One time I drop at 280 deg and turnaround will be 168 deg, the next roast I may drop at 280 deg and turn around may be 198 deg. In my mind I did the same thing but got really different results, any hints for me to try? What I am doing now is after a roast, I kill the gas, open air to full after a few min when BT gets under Drop temp I turn on the gass low set air to med, BT slowly rises. When it hits Drop Temp I drop the beans.
As soon as I drop I set air to min and flame to med-high. After all this now question #2 How shoud I guage the heat stored in the drum better. Sorry for the long guestion.
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I dont understand why you turn temps are varying so much? Are you doing several batches consecutively? Are the batches the same size, of the same bean? I have learned that 8.8 lbs is the sweet spot for my machine. When I first start roasting, I drop at around 315, and turn at 150. As the drum heats up, I lower my drop temp a couple degrees each roast, and my turn remains at 150. I don't what would explain the dramatic differences in turn if you are using the same amount of the same kind of beans?
Oh, and when I say that my "sweet spot" is 8.8 lbs, I mean that I can drop that amount in the roaster with full gas / full air, and reach 341 between 7-8 minutes.
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I have been roasting 1 pound batches, This gives me more roast to work out best roasting practices but my roaster does better with 2.5 pound batches. Thats just too much coffee for me, I do not sell. I just give it to friends and family. I like to have 3 or 4 different kinds roasted variety is a good thing. :)The problem does seem to get worse the more batches I roast but I am not sure, maybe I should think of a lower and lower drop as I roast more batches.
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How long do you let the roaster warm up before your 1st batch? It may be that the early roasts the roaster is not really "hot" yet. As you roast more batches it gets "hot". If I remember you made it with a pretty thick walled pipe. That could take a while to stabilize. Thus you think the drop temp needs to go down, maybe as you roast more your drum is hotter than earlier. Also it may take a while for your drum to get back down to the environmental temp.
for the Air flow. it's about convection vs conduction. I'm no expert on the affect of each on the favor, I just know that Air is yet another variable.... overall it sounds like you are learning your roaster. They each are different.
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I think Milo's hit it on the head. i remember reading a post from you previously about the thickness of the drum, and speaking from experience, the first batch (no matter how long a charge time) is always the prime batch, and will roast 'cooler' than the rest. I can imagine that the drum walls are really heating up during the first batch, pulling heat from the beans as much as to. Thus the following roasts will absorb more heat from the drum than the first, higher turn temp and faster to 1c - end roast, etc.
Once you master that thick walled drum, you're giong to be able to roast a batch of beans with more air-flow control than heat control.
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I think the next roast I will let everything cool off longer between batches, It has some logic the more I think about it. On warm up I have to run the flame on med to get the roaster up to drop temp, but on second and third roast the flame is at its very min to reach drop temp. I should have seen this-but thanks for the help. One more guestion. Do you go by Bean Temp or Evironmental Temp when you drop beans into the roaster. They are only a few inches apart but hardly ever match. I believe the BT is seeing the radient heat off the drum becouse its close to the drum. Does that make sense? I have switched positions of the probes and nothing changes.
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Drop temp is based for me on environment. Also that point is dependent on ambient temp. When it's ball shattering cold, the drop is around 420 and when it's warm, hot or ball blistering hot, the temp is going to be between 395 and 375.
As you said, you're roasting for just you, so I don't know how aplicable this will be, but my first batch is going to be either a decaf or the lightest roast I'm running that night, as as my roaster heats up, my roasts are lined up to go from lighter to darker.. that is to say, as the drum heats up (and it continues to heat up for a few roasts), my roasting 'heats' up too.
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I think the next roast I will let everything cool off longer between batches, It has some logic the more I think about it. On warm up I have to run the flame on med to get the roaster up to drop temp, but on second and third roast the flame is at its very min to reach drop temp. I should have seen this-but thanks for the help. One more guestion. Do you go by Bean Temp or Evironmental Temp when you drop beans into the roaster. They are only a few inches apart but hardly ever match. I believe the BT is seeing the radient heat off the drum becouse its close to the drum. Does that make sense? I have switched positions of the probes and nothing changes.
My drop temp is based on bean probe; I drop around 315. Whatever you do, its gonna be specific to you and your machine. Notice how different Gratefulroast's and my numbers are, but I'd imagine that we both turn around 150 bean temp, at around 1:20.
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I did some roasting this weekend and had a lot better control of the turnaround. With the help of people here I realized that the residual heat was the problem. After a roast I would blow the shop vac under the drum while I was packing the beans and weighing out the next batch, untill all temps were under 200 deg. I used a very low flame with adjust to the air to get Bean Temp and ET very close to each other at the drop temp , this seemed to really help. I was roasting small batches and dropping at 230 deg turn around was 175 to 185 deg. The roast was easier to control with a more consistant turnaround. I saw no sign of scorching, Should I try higher drop temp?
Thanks for the Help!!!
Ringo
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I shoot for an eq / turn temp of under 170 with a fast ramp to just before 1st (360ish or smell).. I open air wide at around 250 and keep the heat on blast to ramp up as fast/slow (makes sence to me!) as possible ... just before 1st I ease off the heat and try and almost coast through the crack. Depending on the bean and the roast degree, I either leave the heat on low and ride the roast till drop or bring up the heat to medium / high just after first is done till the bean goes exothermic .. then it's a no heat coast till it drops. Air flow is either 100% open or close for me.. but I'm still a noob, so it's all open to progression.
Where are you at during 1st? 2nd? I'm reading environmental temps with the probe at about 10:45.
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1st for me is between 365 and 375 deg. I do not roast into 2nd so not sure were that would come in at. I will pull a roast 385 to 400 on the BT. I look for a smooth skin after 1st, and try roast 3 min after a good 1C. I am really changing things around a lot right now trying find the best way to roast. To be honest I think I built too much into this roaster, too much heat, too much air, too much steel and too many temp probes. An old time drum roaster would like to have too much, he would only use what he needs. For a nubbie the leaning curve is slow. I am getting better, this drop temp was a "BIG" help. I think the DP Ethiopians are better in the drum than the Behmor now, The Hard wet process beans seem a little flat.
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For a nubbie the leaning curve is slow.
I think for any new roaster the learning curve can be slow. Think about how much you are learning. There is both science and art to coffee.... neither can be left out and both have to be learned.
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Is there any more to discuss regarding the Ambex?
I just read this thread and would love to hear more discussion.
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A very good looking YM2K sold on fleabay this week; $4100, included some ductwork and a 100lb. propane tank. The main thing that kept me from winning it was that it was an 8-hour drive both ways to pick it up. But I truly see a roaster like this in my future.
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I watched and bid on that YM-2.
He was going to allow an equipment carrier to pick it up if I won the auction, but the freight pushed it beyond what i wanted to spend.
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Since I've had my Ambex the temperature readings never seemed right to me.
1st crack beginning was almost always between 385 - 390 degrees F
2nd crack beginning was at 412 - 416
These readings were very consistent. However, the issue I see with this is there is only a measured maximum difference of 31 degrees between the beginning of 1st and the beginning of 2nd. So it's very difficult to judge if If I was at C+ vs FC except for looking at the beans. I wasn't happy with the minor inconsistencies I've been getting and assumed I was actually measuring the environment temperature near the top of the bean mass (possibly an occasional bean or two coming in contact with the probe)
Back in my sonofresco days I had a temperature probe and measured temperatures closer to:
1st crack (which I could hear) started at about 400 - 415
and I'd cool at about 438 - 450 depending on the bean
George Steinert's Degree of Roast/Temperature chart:
Degree of Roast Temp
Green Unroasted 75
Starting to pale 270
Early yellow 327
Yellow-Tan 345
Light Brown 370
Brown 393
1st Crack Begins 401
1st Crack Under Way 415
City Roast 426
City+ 435
Full City 446
Full City+ 454
Vienna (Light French) 465
Full French 474
Fully Carbonized 486
Immanent Fire 497
So at Coffee Fest I spoke to Terry from Ambex about it and he said I should be reading a higher temperature and he recommended replacing the thermocouple, making sure I get the probe into the bean mass.
I replaced it with the 4" probe Ambex sells and got the probe placed a low as I could. My readings went up about 2 degrees. I still wasn't happy so I started doing some research on probe placement and looking at it more from an engineering standpoint. I came across a good article...... on the Ambex site (http://www.ambexroasters.com/information/read/probes.html?txt=1)
(http://www.ambexroasters.com/art/articles/probes/coffee3.jpg)
In trying to estimate how deep the beans would be in my drum I determined that a 4" probe is not long enough to get through the compression fitting in the wall of the roaster, plus the bend radius and the down near the stir veins as per the above image. In fact with the new probe I was a good 2" above the stir veins. So I found (in my goodie box) a 6" probe. I installed it and got the probe tip approximately 1/2" above the stir veins, checked for interference and then roasted a batch. The results were what I'd hoped for.
1st Crack began 401
2nd Crack began 437
I may try to get the probe even closer so I can get more consistent readings with only 1 lb of beans in the drum. The 6" probe gives me much more flexibility in probe placement.
You don't need to buy the probe from Ambex. Any J or K or T type, 1/8" diameter probe will work. Just make sure you change the PID if you change from a J type to a K or a T type.
I'll post photos in the next week or so, I didn't get around to taking any last night.
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Great info Larry. I know my bean probe is too short, no more than 2"; I think it must have broken off but the end of the probe is smooth and round so I don't know for sure but I need to replace it.
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Looks like I have some work to do, my 1c comes in at 367 with a small load and 385 with a full load. Thanks for the info.
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I hit 1C 385-390, 2C 430-435
I have a 6" probe that is just left of center when you open the door, and maybe 3/8" off the drum floor.
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With 1kg of beans in my YM2 I see temps that are in what I feel is a "correct range" for the bean, typically
375-385 for 1C and 2C doesn't happen until upper 430, 440 depending on the bean type.
1lb batch is a complete different story and I'm sure correlates to Larry's probe placement discussion here. I generally stick with 1kg minimum load. My roaster was manufactured in 2009, I will have to look inside to determine what length of probe is in it.
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Interesting...my probe is 2" and there is no bend to it inside the roaster to come closer to the drum wall. It is mounted on the inboard side of the site glass window, It would be 1 3/8" closer to the drum if the glass mounting were merely rotated 180 degrees...hmmm
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I moved my probe before I roasted yesterday, I think it was a good thing. 1st crack came in around 385 to 389 degs. This is better, and small loads and large loads seem the same. This will really help with controlling the roaster. One strange thing now is when I am in the 340 to 350 degs range now bean temp is higher than environmental temp. Bean temp continue to rise but environmental drops as I try to slow the roast before it gets into 1st crack. I am guessing the heat is coming off the drum during this stage, I did not change how I am roasting so this has been going on before I just did not know. I will have to do some testing with a little higher airflow and see if the cup improves.
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I have decided to add a separate fan for my bean cooling. This is something I spoke to Terry at coffee fest. I've never liked that it take 6 -8 minutes to cool the beans in the Ambex. Seems the airflow is underpowered for cooling and I can't start another roast until the beans are cool.... I ordered a high temperature blower and some duct parts. I plan to use one of the cooling tray cleanout panels as the exhaust port.
I may also add a chaff collector as part of the new exhaust design. Pictures, parts list and drawings coming soon.
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I have decided to add a separate fan for my bean cooling. This is something I spoke to Terry at coffee fest. I've never liked that it take 6 -8 minutes to cool the beans in the Ambex. Seems the airflow is underpowered for cooling and I can't start another roast until the beans are cool.... I ordered a high temperature blower and some duct parts. I plan to use one of the cooling tray cleanout panels as the exhaust port.
I may also add a chaff collector as part of the new exhaust design. Pictures, parts list and drawings coming soon.
Larry, I have a supplemental fan for the cooling tray. I don't know if mine is high temp. blower or not, because it's external, in a (not so well designed) sheet metal box with an intake and outflow. The vent pipe coming out of the cooling tray is long enough that by the time the air gets to the fan, it's cooled somewhat and when it travels through the outflow pipe (a standard dryer metal hose) it's cool to the touch. The extra fan really does the trick - the beans are cool to the touch around 3-4 mins., and without it takes about what you listed above. It also lets me roast back-to-back so I can control the airflow through the drum if I want too. I'm curious how the US Roasters and Probat handle cooling tray airflow - I worked on both during a roaster maintenance class and for the life of me, I don't remember if they have internal supplemental cooling fans or not...
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Here is a photo of my 6" probe. I've only done 1 roast with it.... kinda roasted 25 lbs with the one Ambex sent me before I put this one in. Tomorrow I'll roast a few batches and will report on the consistancy... I'm going to try 1 1/2 lbs and see how it reads.
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I got the duct fittings in the mail yesterday for the blower. I had to build an adapter place from a 2 1/2" x 3 1/4" rectangular hole to a 4" round hole. Had company tonight so didn't get to finish cutting the hole in the steel.
As soon as I finish the install I'll post photos.
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Here is a photo of my 6" probe. I've only done 1 roast with it.... kinda roasted 25 lbs with the one Ambex sent me before I put this one in. Tomorrow I'll roast a few batches and will report on the consistancy... I'm going to try 1 1/2 lbs and see how it reads.
Larry, where did you source your 6" probe? I'm pretty sure my YM-5 doesn't have one that long and my YM-15 is a stubbie. I know my temps are off because it doesn't reach as far into the bean mass as it should.
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Here is a photo of my 6" probe. I've only done 1 roast with it.... kinda roasted 25 lbs with the one Ambex sent me before I put this one in. Tomorrow I'll roast a few batches and will report on the consistancy... I'm going to try 1 1/2 lbs and see how it reads.
Larry, where did you source your 6" probe? I'm pretty sure my YM-5 doesn't have one that long and my YM-15 is a stubbie. I know my temps are off because it doesn't reach as far into the bean mass as it should.
I got it from my stash of thermocouples ;D
I bought it a few years ago on ebay to fit into my sonofresco.
Go to www.omega.com (http://www.omega.com/ppt/pptsc.asp?ref=TJ36-ICIN&nav=GRES) and search for TJ36-ICSS-18G-6... It should be about $30 or you can look for one on ebay. BTW the 36 in TJ36 is the lengh of wire in inches... if you need longer you can get an online quote for longer length.~ $1 / foot more. You can also add an Armor shield to the outside of the wire. for a few dollars more. They will build it how you want it.
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If you are going to add a 6" probe, and bend it to where it needs to be, make sure when you bend it, you brace it against something about as thick as your finger. Like a small piece of a wooden dowel or something like that. Otherwise it will want to bend at 90degrees where the probe meets the inlet; it will break.
Also, make sure you're not putting the tip of the probe to close to the drum, or your temperatures will still be inaccurate, just in a different way.
That said, getting the correct length probe and placing it where it needs to be is essential. The fact that these roasters are being sold with 2" probes sticking straight into the drum makes me wonder.
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The fact that these roasters are being sold with 2" probes sticking straight into the drum makes me wonder.
Yeah, it especially makes me wonder when Terry Davis did the article in this months Roast magazine about it! ???
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I did 6 roasts yesterday with varying amounts of beans
With a 1 1/2 lb charge of green the readings are accurate. However if I dropped down to 1.2 lbs charge it depended on the beans. One load the temp read correctly but the second didn't. I may try to lower the probe even lower to see if I can get consistent readings with a 1.2 lb charge. I seldom roast only 1 lb, but it would be great if I could do it with constant temp readings.
I suspect the factory install reads environment temp. Terry eluded to that when I spoke with him a few weeks ago.
I also finished my cooling fan modification. With a 3 3/4 lb charge it cooled to room temperature in under 3 minutes. I'll upload some photos and a bill of materials for folks. I think it cost me about $125 to do the mod. with the blower ducting and blower adapters.
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^^^^^ Ay, caramba! Now there is some cooling!
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Ok, here are a couple photos.
Parts
Dayton 1TDV2 High Temperature Blower, 115 Volt, 130 CFM - Amazon.com $68
4" Flange Kit - Growannex.com - $13 (2 flanges, 1 to connection to ambex and the other to the outlet of the blower)
Active Air 4" Flange - Growannex.com - $6 (inlet port of the blower)
4" y-pipe - Home Depot - $12
4" adjustable elbow - $5 home Depot
Aluminum Duct tape - $15
High temp gasket - Furnace supply store $10 (used between the steel plate and the blower and the steel plate and the outlet flange)
6"x6" steel plate (had to make a round to rectangular adapter for the outlet port of the blower) $10
Total ~$139
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Well done Larry!
:icon_thumleft:
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I ran into a glitch today. Must be the atmospheric pressure.... but smoke started come out the been cooler... so I turned the cooling fan on... about 30 seconds later smoke blowing out the bottom of the roaster.... I think I either need a separate exhaust through the window for the bean cooler or a backdraft damper in the bean cooler line..... but boy does it cool the beans!
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My USRC uses a separate duct for the cooling tray...
-Stubbie