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Enhancing My HotTop (2 of 5)-Monitoring Bean Mass Temperature
ciel-007

Quote

century wrote:

Does the permanent and temporary achieve the same accuracy in temp readings?



With either mod, the BMT probe ends up in approximately the same location in the chamber, and approximately the same depth in the bean mass; so that should not affect accuracy significantly.

Perhaps the most important factor in accuracy is the quality of the probe itself. I opted for Omega primarily because of their reputation for precision instrumentation. However, other HRO members may be able to recommend other good brands that cost less.
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
 
smico

Quote

century wrote:

Does the permanent and temporary achieve the same accuracy in temp readings?

Im not handy with this stuff but can work out the temp. version easily enough (with Randy's template), so its a better option.
But would like to know if there is a difference in readings and/or accuracy.
Only now I saw this question...

My first installation was based on Randy's template.

As probes ended up at the same hight, readings were very close.

I would say the thermal insulation for ET probe is important whether you use Randy's template or backwall. ET temperature is leading indicator for BT, and you want to see the change as soon as possible.

And lastly, Randy himself installed thermocouples on the backwall as permanent solution.

Cheers,

Miroslav
Hottop B2 + HTC, Cremina 83, OE Pharos, Brewtus IIIR, Baratza Vario
 
MarkJames
I know I'm a little late to this party but I just got here :)

I thought I'd put in my two bits. I installed a K-style probe in my HotTop a few months ago but took a different approach. I read all the articles that you referenced in this very thorough post and then decided that I wanted a thermocouple that was completely immersed in beans.

To that end I purchased a 4inch K-style grounded thermocouple. It's impossible to mount this to the roaster back without cutting the cross braces of the drum as the drum would otherwise break the thermocouple immediately.

So I removed the cross braces.

That caused the drum to wobble when turning. In for a penny and all that jazz I then added two ball bearings to the back of the roaster that rest against the inside surface of the drum. With those in place the drum spins true (actually it spins better than it did new) and my thermocouple lives happily in pretty much half the drum's worth of bean mass.

I don't have anythiing to compare it to other than the HT thermocouple (which is useless on mine) but I get very consistent results from it.

I've yet to install an ET probe and I'm not really sure I will but if I do I think I'll get a K-style probe like the ones in the new HT roasters and mount it near the top out of the bean mass.

There's a picture of the bearings and the 4" thermocouple in my post about a HT bean dumper.

Lots of ways to skin a cat!

Mark
 
smico
Hi again Mark.
Ciel's series became reference for HT modifications and it would be great if you can repost the picture here. Your original approach is quite unique.
As for the ET probe, I would highly recommend thermal insulation from the hot backwall.
I forgot to ask, are the bearings inside or outside the drum. Inside I guess, but just to be sure.
Hottop B2 + HTC, Cremina 83, OE Pharos, Brewtus IIIR, Baratza Vario
 
MarkJames
No problem at all. I took a few more photos to help out.


Sorry that my HT is so nasty looking inside. I've had it since 2004 or so and it's done thousands of roasts since. I've long ago stopped being too fussy about cleaning it.

I think you can see in the photo the cut ends where the crossbrace was removed from the drum. I wasn't planning on documenting this so I don't have a picture of the drum with crossbrace in place. Perhaps someone who does could post one for a contrast or send it to me and I'll edit this post with it.

The back wall photos I think you can see the bearings mounted against the back wall with cap head screws secured on the other side with nylocks. I carefully marked these with them on the end of a magnet with the drum in place and then drilled the holes and mounted them.

Several problems arose once they were in.

The first was that the spiral bean agitator wire on the drum extended too close to the back edge and was hitting the bearings so I had to grind that back with a dremel tool.

The next problem was that the drum itself turned out not to be a perfect circle so as it spun it got to narrower and wider portions. This put stress on the motor that made me unhappy. It turned out that the solution to this was quite simple - just leave the nut holding the bearings to the back wall a little loose so they can wobble a couple of mm. That solved the problem instantly and there have been no issues since.

As it rotates you occasionally hear a bean get squeezed between the drum and bearing but it just pops back out immediately and doesn't seem to cause any trouble. I've done about 30 roasts with it like this so far and can't see any issues.

You can see how long the thermocouple is in the chamber. I don' t know if this is a good thing or bad thing but my gut said that 'bigger is better'

Mark
MarkJames attached the following images:
backwall2.jpg backwall1.jpg drumcut.jpg
 
MarkJames
Sorry - I guess there's a time limit on editing a post. This photo belongs with my last post.

I took a picture of the drum in place showing the position of the bearings.
MarkJames attached the following image:
druminplace.jpg
 
smico
Thank you for reposting Mark.
I remeber now seeing similar solution for the big boys, but this is the first time I see it implemented on the Hottop.
Miroslav
Hottop B2 + HTC, Cremina 83, OE Pharos, Brewtus IIIR, Baratza Vario
 
ciel-007
Temporary BT and ET Probes

Here's an alternative way of installing Temporary BT and ET probes on your Hottop. The photos were posted by JK at Home-Barista during 2012.

Ciel
ciel-007 attached the following images:
temporary_probes_jk_1.jpg temporary_probes_jk_2.jpg

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
 
ciel-007
Temperature Probes:
Accurately Measuring the Advancement of Coffee Roasting


Quote

ciel-007 wrote:
Just in case some of you may be thinking about installing a temperature probe inside your roaster, here is a link to a helpful article:

http://www.ambexroasters.com/information/read/probes.html

Among other things, Davis and Ribich identify the types of probes that are suited for coffee roasting, and provide advice for the correct placement of the probe in the chamber. The article has lots of practicle advice. For example, your temperature probe should:
- be mounted on the side of the drum that is rotating the beans in an upward direction
- be completely submerged in the bean mass at all times
- extend into the bean mass at a depth that is equal to 10 times the diameter of the probe
- etc?

The authors feel that: ? no tool has had as profound an effect on the advancement and growth in coffee roasting as temperature probes?.


Some time ago, I had posted a link to Ambex Roasters. That link contained a very helpful article by Davis and Ribich about probes, and how to properly install them. Following that post, Ambex Roasters re-configured their web site, and the link collapsed. I just re-discovered the article by Davis and Ribich, and am posting a fresh link below. If you're serious about Temperature Probes: Accurately Measuring the Advancement of Coffee Roasting reading the article by Davis and Ribich a must.

http://www.teaand...coffee.htm

Ciel
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
 
JitterzZ

Quote

ciel-007 wrote:

Temperature Probes:
Accurately Measuring the Advancement of Coffee Roasting


Quote

ciel-007 wrote:
Just in case some of you may be thinking about installing a temperature probe inside your roaster, here is a link to a helpful article:

http://www.ambexroasters.com/information/read/probes.html

Among other things, Davis and Ribich identify the types of probes that are suited for coffee roasting, and provide advice for the correct placement of the probe in the chamber. The article has lots of practicle advice. For example, your temperature probe should:
- be mounted on the side of the drum that is rotating the beans in an upward direction
- be completely submerged in the bean mass at all times
- extend into the bean mass at a depth that is equal to 10 times the diameter of the probe
- etc?

The authors feel that: ? no tool has had as profound an effect on the advancement and growth in coffee roasting as temperature probes?.


Some time ago, I had posted a link to Ambex Roasters. That link contained a very helpful article by Davis and Ribich about probes, and how to properly install them. Following that post, Ambex Roasters re-configured their web site, and the link collapsed. I just re-discovered the article by Davis and Ribich, and am posting a fresh link below. If you're serious about Temperature Probes: Accurately Measuring the Advancement of Coffee Roasting reading the article by Davis and Ribich a must.

http://www.teaand...coffee.htm

Ciel


Updated link for those interested: Temperature Probes: Accurately Measuring the Advancement of Coffee Roasting By Terry Davis and Paul Ribich http://roastbrewd...robes.html
 
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