HELP -- I can not hear any cracks

green beans

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Jan 30, 2007
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To give everyone some background I recently started roasting on a propane YM2, Costa Rica beans. I am having difficulty getting the beans to develop while roasting.

Here is an example: I roast 2 pounds and I drop them in at 420 degrees

-the temperature goes down to about 355 and steadily rises to about 390 at 9 minutes.

-at this time the beans are still looking very light and the heat continues to climb up to about 460 at 18 minutes

-i take the beans out even though they are not looking too dark but i do not think they should roast for too much longer time wise. I roasted one batch until it was looking dark (still not oily) and it took almost 30 minutes and tasted burnt.

I do not know a lot about roasting I am the first to admit that but I am trying to figure it out. Where is my major malfunction? I have not heard a single crack 1st or 2nd. The beans are always really light in color and seem to darken in splotches when it they do darken.


Any guidance is hugely appreciated.
 
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green beans

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Great thought ElPugDiablo it had not even occurred to me that the probe may need to be calibrated or adjusted.

There was one batch where I kept the temperature very high (never went under 400). The beans looked good but were totally baked/burnt to taste so that could mean that the temperature is mostly accurate.
 

Davec

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Oct 18, 2006
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it's a bit odd, you seem to be using quite a high drop temperature....I used to drop into a 25kg commercial probat at a substantially lower temperature than that!

Then the recovery of temperature also seems a tad slow and it drops a lot considering how high your drop temp is?? you also seem to be achieving quite high temperatures and ones at which you should definitely hear 1st and second crack.

yet you say the beans are either uneven or burnt.

Just a guess as I don't know the roaster....but I would be looking at airflow! if your airflow is not controllable, then remove the blower and check it, also check the cyclone and the stack for obstructions, sharp bends, facing into wind??...I say this because it sounds like somehow your not getting enough airflow (and hence convective heat through the roaster).
 

ElPugDiablo

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Jul 16, 2004
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green beans said:
To give everyone some background I recently started roasting on a propane YM2, Costa Rica beans. I am having difficulty getting the beans to develop while roasting.

Here is an example: I roast 2 pounds and I drop them in at 420 degrees

-the temperature goes down to about 355 and steadily rises to about 390 at 9 minutes.


-at this time the beans are still looking very light and the heat continues to climb up to about 460 at 18 minutes

-i take the beans out even though they are not looking too dark but i do not think they should roast for too much longer time wise. I roasted one batch until it was looking dark (still not oily) and it took almost 30 minutes and tasted burnt.

I do not know a lot about roasting I am the first to admit that but I am trying to figure it out. Where is my major malfunction? I have not heard a single crack 1st or 2nd. The beans are always really light in color and seem to darken in splotches when it they do darken.


Any guidance is hugely appreciated.
What temperature is it measuring? Sounded like it is an atmospheric temperature reading not a bean temperature reading.
 
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green beans

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Thanks Davec, I wondered about airflow but was not sure how it is controlled. I know how to turn the air to the cooling bin on and off but not air around the drum.


There is a bean probe ElPugDiablo going straight into the roasting drum. I have not tested the probe yet for temperature reading.
 

Davec

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On the roaster I used there was a little wheel on the outlet tube from the drum. It may be that your airflow is not controllable, if so then it might be worth thinking about a blockage or if it's an old roaster, mabye the blower needs cleaning.

It's just what you describe is pretty much what you might get on a roaster trying to do most of it's heating via conduction from the drum rather than hot gases, especially the burnt taste and scorching together with the long long roast times.

Is the roaster new or old, hows the chaff clearance from the drum (do the beans come out very chaffy)?
 

topher

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have you thought of doing a full batch? Try doing a full 5 pounds of coffee? Try that and see if you can hear anything then.
 
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green beans

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I do have that control for the burner flame, a manual knob on the control panel. I do adjust it but I will be the first to admit my biggest problem probably is me being new to roasting.


I have done about 3 pounds but never 5 I figured I would try to figure things out with a smaller amount. Is it possible that I may hear cracks doing a full batch (5 lbs.) roasting the same way I have been smaller batcher??
 

dcmusichound

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Nov 10, 2007
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Baked beans

There is something very odd about the temperature changes you are seeing. If you truly have a bean probe, rather than something measuring the roast chamber temperature, I would expect the turn temp to be much lower, like in the 150 degree range. Conversely, beans that reached 460 should be dark and oily. However, those temperatures would make a lot more sense if you are, in fact, measuring the roast chamber temperature. According to Ambex, a roast should take around 15 minutes, but in my RK I have had successful roasts that last as much as 30 (although that will not bring out as much complexity). But you absolutely should be hearing the cracks.

If we assume that you are measuring the roast chamber temp, which would be consistent with the light color of your beans and the lack of audible cracks, I would guess you are baking the beans rather than roasting them. I would recommend cranking up the heat a little bit more. Think about getting the temp up to around 475 within 5-6 minutes and hitting first crack in 12 to 14 minutes, at which point you can lower the heat and let the beans cruise through 1st and onto second.
 

Davec

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It's just that most roasters I have come into contact with are much harder to roast in and control properly, when roasting below their designed batch size.

I was talking to a roaster only the other day who had tried to roast less than the normal batch size of Monsooned Malabar in a big roaster....needless to say, it had not gone well, small batch is bad enouygh and coupled with the MM was a recipie for disaster :-D

However, apparently there are a few roasters that apparently like to roast at about 80% of their maximum? But not the ones I have come across.
 

lizzy

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Mar 6, 2006
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I too would suspect the temp isn't as high as it says. clean out the little squirrel fan, have someone check the flame and make sure it is where it should be. I have a noisy YM2 and I can clearly hear both cracks and roast 2 k in 15-18 minutes.
 

antfuzz1

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May 7, 2007
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Green beans,

Your drop temp is waaay tooooooo high for such a small batch. The bean probe is not in the bean mass. You are getting false readings. Try this profile.

Ambient temp in my shop is around 60º to 65º.
Make sure roaster is fully warmed up.
Start with 3 lbs. 12 oz. of greens, Will yield 4 12oz. bags.
Drop beans at 260º
It will bottom out around 175º or so.
Temp will start to rise and at about 2 min you'll be at 190º to 200º
Temp will rise 30º a min. for the next 2 maybe 3 min.
Moisture releases and temps will go up 20º a min.
At 9 mins. you'll be at 370º
First crack will be at 385º to 395º
From there you're on your own.

This is just a very rough guide. The artistry is figuring out what works with which coffee.

For easier reading this is a profile for Costa Rican

2:00-197º
3:00-233º
4:00-263º
5:00-286º
6:00-309º
7:00-330º
8:00-350º
9:00-369º
First crack at 384º 9:49 second crack will be 2:30 to 3:00 after 1st.

Hope this helps and remember this is a rough guide.
 
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green beans

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Thank you all for the helpful thoughts.

Hey lizzy thanks for the post I will be sure to check the temperature and make sure it is accurate.

So antfuzz1 those temperatures are way different than what I was attempting. Would my temperatures be closer if I was doing a full batch perhaps?? I will give that profile a shot and let you know how it goes, thank you.
 
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