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10/19/2021 6:22 AM
Welcome tarunk!

10/17/2021 12:40 PM
Ploni and nader fouad, Welcome!

10/15/2021 2:19 AM
merlot85, maycondelpiero and hoeltz, Welcome !

10/14/2021 10:06 AM
Thanks for the addition to the group. Seriously considering building a drum roaster along the lines of oldgrumpus's. Love the design and craftsmanship.

10/14/2021 4:00 AM
Morning, ar3mia ! and... coffee drink

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measuring temperature - before, in, or after the beans?
yamhill
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?

John
jmrmotorhead
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.

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

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
yamhill
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.

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

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