<p>I too have an RK Drum used over an old Brinkmann All-In-One cooker with an 55 rpm electric motor attached. <strong>I wish I could get bean mass temp! And a trier... fantastic.</strong> But all I can do is put a thermoprobe just below the rotating drum and listen. I have a circular 1/8 inch steel plate sitting between the flame and drum so the probe is not exposed to direct flame.</p>

<p>I do know that the temp at the probe is greater then the temp of the drum. I can take the drum temp using a Raytek infrared gun.</p>

<p>If you are going to be forcefully venting hot air out, I would take the temp at that point. Easy access and you can certainly make correlations between bean mass temp, vent temp and first crack. If you are going to snake a probe into the hot space around the drum, I would make sure it wasn't exposed to direct flame - over the drum is where I would go. I can't do that with my setup because I have to lift the drum up and out to empty it. I'm going to guess you will find out that it's interesting data, but not essential. Happy to be proven wrong though!</p>

<p>good luck, sounds like fun!</p>

CC BY-SA 3.0
2016-10-18T21:07:25.753Z
Well, I'll know the truth about bean temp - I won't need to make correlations to know the bean mass temp because I'll know it already. But I see many professionals using two probes. I supposed it was to anticipate where the roast is going while bean mess tells you where it is now. So it is a question of is the exhaust port the best place to do that or in the fluid bed between the drum and the flame screen like what you are doing. Right now the probe is just under my drum in my behmor
Nick
CC BY-SA 3.0
2016-10-18T18:50:05.023Z
2016-10-18T18:50:05.023Z
Jim
<p>I'm not very familiar with the Kaldi roaster. From what little I've read, most buyers are pretty happy with it. I built a home roaster about a year ago using equipment from RK Drums, which requires a dedicated gas grill. I'm really happy with the results I get from this setup. I noticed the Kaldi also requires the purchase of a gas burner but what size and form is it? I use a single thermocouple that mounts very close (~1/2") to the drum. I'm not sure how you plan to drop one right in the bean mass while the drum is rotating. Again I'm not very familiar with the Kaldi so maybe you've worked this out. Using forced air might help if you think the beans aren't getting even temp distribution. I don't use forced air. The thermal mass of the grill cavity along with the bean rotation seems to distribute the temperate quite evenly. Wherever you place the probe, as long as you can get a consistent and reliable reading you should be able to build your roast profiles accordingly. Good luck and I look forward to your updates with the results!</p>

CC BY-SA 3.0
2016-10-17T16:19:48.490Z
The drum has an opening that it rotates about on the front. This one opening is used for charge, drop (you physically to the unit), the stock thermometer, and the trier. There is a manifold place that allows you to keep the trier and the thermometer in place at charge. At drop you pull the manifold off and dump the unit onto whatever separate cooling system you use.
Nick
CC BY-SA 3.0
2016-10-17T16:21:07.847Z
The impeller I would like to add would pull air out the bean hopper port. Similar to a probat style roaster (I think the Huky 500t does it the same). I have two reasons for wanting to do this mod. 1) I want to vent chaff and smoke out a window, 2) I want to push the limits (or exceed) the charge size. Kaldi makes one higher end machine that I believe can do over a pound but requires airflow. The impeller would force conduction and allow me to have greater responsiveness at higher charge sizes.
Nick
CC BY-SA 3.0
2016-10-17T16:25:42.990Z
The burner I intend to use will be a 10 - 15k butane BTU camp stove.
Nick
CC BY-SA 3.0
2016-10-17T15:56:55.837Z
2016-10-17T15:56:55.837Z
user3314
<p>I am considering upgrading my home roasting setup to a gas <a href="http://rads.stackoverflow.com/amzn/click/B00SM3HXXY" rel="nofollow">Kaldi Wide</a>. Part of what is so appealing is that this roaster is so bare bones and will be easy to modify to try different things.</p>

<p>I am going to drop a thermocouple into the bean mass to get my bean temp. Beyond that I want to measure the environment temperature as well. Where should I measure that? Somewhere above the drum? As is, this roaster has no forced convection. I am considering adding a duct hose and impeller over the bean hopper with a damper depending on how things go after my first few roasts with no air flow. If I did that would it be more valuable to look at this exhaust temperature? I am under the assumption that the advantage to trying to get an environmental temperature is that it would be more responsive than the actual bean temperature to show you where the roast is going - if I am thinking about it wrong please let me know!</p>

<roasting><home-roasting>
Where to measure ET on drum roaster
Nick
# Where to measure ET on drum roaster

(Asked by: username_0 on 2016-10-16)

I am considering upgrading my home roasting setup to a gas [Kaldi Wide](http://rads.stackoverflow.com/amzn/click/B00SM3HXXY). Part of what is so appealing is that this roaster is so bare bones and will be easy to modify to try different things.

I am going to drop a thermocouple into the bean mass to get my bean temp. Beyond that I want to measure the environment temperature as well. Where should I measure that? Somewhere above the drum? As is, this roaster has no forced convection. I am considering adding a duct hose and impeller over the bean hopper with a damper depending on how things go after my first few roasts with no air flow. If I did that would it be more valuable to look at this exhaust temperature? I am under the assumption that the advantage to trying to get an environmental temperature is that it would be more responsive than the actual bean temperature to show you where the roast is going - if I am thinking about it wrong please let me know!

**Tags:** roasting, home-roasting


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## 2 answers

### Answer by username_1 on 2016-10-18. Score: 1

I too have an RK Drum used over an old Brinkmann All-In-One cooker with an 55 rpm electric motor attached. **I wish I could get bean mass temp! And a trier... fantastic.** But all I can do is put a thermoprobe just below the rotating drum and listen. I have a circular 1/8 inch steel plate sitting between the flame and drum so the probe is not exposed to direct flame.

I do know that the temp at the probe is greater then the temp of the drum. I can take the drum temp using a Raytek infrared gun.

If you are going to be forcefully venting hot air out, I would take the temp at that point. Easy access and you can certainly make correlations between bean mass temp, vent temp and first crack. If you are going to snake a probe into the hot space around the drum, I would make sure it wasn't exposed to direct flame - over the drum is where I would go. I can't do that with my setup because I have to lift the drum up and out to empty it. I'm going to guess you will find out that it's interesting data, but not essential. Happy to be proven wrong though!

good luck, sounds like fun!

> **Comments:**
> **username_0**: Well, I'll know the truth about bean temp - I won't need to make correlations to know the bean mass temp because I'll know it already. But I see many professionals using two probes. I supposed it was to anticipate where the roast is going while bean mess tells you where it is now. So it is a question of is the exhaust port the best place to do that or in the fluid bed between the drum and the flame screen like what you are doing. Right now the probe is just under my drum in my behmor  

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### Answer by username_2 on 2016-10-17. Score: 1

I'm not very familiar with the Kaldi roaster. From what little I've read, most buyers are pretty happy with it. I built a home roaster about a year ago using equipment from RK Drums, which requires a dedicated gas grill. I'm really happy with the results I get from this setup. I noticed the Kaldi also requires the purchase of a gas burner but what size and form is it? I use a single thermocouple that mounts very close (~1/2") to the drum. I'm not sure how you plan to drop one right in the bean mass while the drum is rotating. Again I'm not very familiar with the Kaldi so maybe you've worked this out. Using forced air might help if you think the beans aren't getting even temp distribution. I don't use forced air. The thermal mass of the grill cavity along with the bean rotation seems to distribute the temperate quite evenly. Wherever you place the probe, as long as you can get a consistent and reliable reading you should be able to build your roast profiles accordingly. Good luck and I look forward to your updates with the results!

> **Comments:**
> **username_0**: The drum has an opening that it rotates about on the front. This one opening is used for charge, drop (you physically to the unit), the stock thermometer, and the trier. There is a manifold place that allows you to keep the trier and the thermometer in place at charge. At drop you pull the manifold off and dump the unit onto whatever separate cooling system you use.  
> **username_0**: The impeller I would like to add would pull air out the bean hopper port. Similar to a probat style roaster (I think the Huky 500t does it the same). I have two reasons for wanting to do this mod. 1) I want to vent chaff and smoke out a window, 2) I want to push the limits (or exceed) the charge size. Kaldi makes one higher end machine that I believe can do over a pound but requires airflow. The impeller would force conduction and allow me to have greater responsiveness at higher charge sizes.  
> **username_0**: The burner I intend to use will be a 10 - 15k butane BTU camp stove.  

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