Not a member yet?
Click here to register.

Forgotten your password?
Request a new one here.
You must login to post a message.

02/04/2023 1:40 PM
Welcome, ediblemanager

02/02/2023 4:22 PM
bcoffeedrinker Welcome

01/31/2023 1:17 AM

01/29/2023 4:55 AM
Welcome, drygrounds and CarlHaberfeld,

01/28/2023 5:42 AM
ramsamorrow, VirTERM and Columbia, coffee drink

In Memory Of Ginny

Latest Donations
dmccallum - 10.00
JackH - 25.00
snwcmpr - 10.00
Anonymous - 2.00
Anonymous - 5.00
Users Online
Guests Online: 16

Members Online: 0

Total Members: 7,788
Newest Member: ediblemanager

View Thread

Who is here? 1 guest(s)
 Print Thread
measuring temperature - before, in, or after the beans?
I'm roasting with a 72000 popper, and I'm having trouble controlling the roast. I first roasted with a modified pumper 1150 watt version IIRC - for about 100 roasts until the bottom bushing fell out of the motor. The 72000 reacts differently, and the roaster control isn't intuitive.

I have separate fan and heat controls, and I've been surprised sometimes by how much heat I get when turning up the fan speed. Other times I get the cooling I expect. My guess is that I don't have a good grasp of the temperature of the heat entering the bean mass. Also, the 72000 has a ceramic heat sink that my previous pumper didn't have - complicating the picture.

I want some more insight to the roast. Do you all have any suggestions for measuring the temperature of the air before the bean mass? Pragmatically how and where could I place a probe to do this?

You know, I have had some issues with reading the temperature of my roast since I switched to a temperature probe vs. the hand haled IR temp gun I was using. Before I could aim the gun down my RC and get an accurate BT reading. However with the prob it seems to be reading the air coming up into the beans rather than the actual bean temp. If your attempting to get a read on the air, not the beans, I would place a probe under where the beans will normally float. Drill a horizontal hole into the roast chamber, under the bean level (once they lighten up a bit) and stick it in so the tip is smack in the middle.

I'm curious to why your heat would increase when you turn the fan up, I have found the higher the fan speed, the less dwell time over the heating element, therefore the air temp is lower.

Can you post a pic of how your thermocouple is placed?

Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
I can post a picture when I get home, but basically the probe is hanging down in the middle of the bean mass. It is literally hanging over the edge of a metal tube that extends the height of the roast chamber. A bend in the wire keeps it off the bottom of the popper and roughly in the middle of the bean mass.

On a related point ..
I roasted a three batches last night and realized that part or maybe all of my confusion possibly has a different root cause. I recently got a TC4 just for data tracking. Right now it just grabs the temperature from the thermocouple in the bean mass. The TC4 / thermocouple consistently shows the temperature at about 375-380 F at the beginning of first crack. Previously my temperature probe, also a type k thermocouple - also hanging in the bean mass and connected to a PID running as a dumb temperature probe - showed 400 F at the start of first crack. This confused me until last night I stuck both temperature probes in the bean mass - and sure enough they give quite different readings. So, now I'm not confused by the reaction of my roaster and the bean temperatures.

I have a different question now (for a different thread) of how I calibrate the temperature readings of the PID and/or the TC4.

Is each TC the same type of wire? (J or K or ...)

Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
yep. Both are type k.
Jump to Forum:

Similar Threads

Thread Forum Replies Last Post
Where do YOU get your green beans? Green Coffee 15 01/05/2023 3:08 AM
EU Green Coffee Beans Sourcing 2023 Green Coffee 1 01/01/2023 8:45 PM
Behmor PID Temperature Controller Behmor 1600 5 11/19/2022 5:53 AM
Can First Crack be detected by Measuring the Intake Air Temp? Gene Cafe Roaster 27 10/06/2022 9:49 AM
Waiting on my Roaster and beans. Roasting Coffee 11 09/23/2022 8:37 AM
Homeroasters Association Logo, and all Content, Images, and Icons © 2005-2016 Homeroasters Association - Logos are the property of their respective owners.
Powered by PHP-Fusion Copyright © 2023 PHP-Fusion Inc
Released as free software without warranties under GNU Affero GPL v3
Designed with by NetriX
Hosted by skpacman