Measuring internal bean temperature?

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
abhishah
Posts: 111
Joined: 11 years ago

#1: Post by abhishah »

Hi,

So finally managed to build my own 2lbs electric fluid bed roaster along with a chaff collector.

Doesnt look all that great, but it roasts pretty well.

Can anyone please suggest how i can measure the internal bean temp for better accuracy?

Thank you!


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Andy
Posts: 242
Joined: 14 years ago

#2: Post by Andy »

Most people do it by positioning a thermocouple or other type of probe in the center of the roasting bean mass. How you do that depends on the design of your roaster. That will give you the BT -- the approximate temperature of the roasting beans. If by "internal bean temp" you mean the temperature of the interior of individual coffee beans as they are roasting, I don't think anyone has devised a way to do that.

Edit: Very cool looking roaster, by the way. Please tell us about it, perhaps in a new thread.

abhishah (original poster)
Posts: 111
Joined: 11 years ago

#3: Post by abhishah (original poster) »

Andy wrote:Most people do it by positioning a thermocouple or other type of probe in the center of the roasting bean mass. How you do that depends on the design of your roaster. That will give you the BT -- the approximate temperature of the roasting beans. If by "internal bean temp" you mean the temperature of the interior of individual coffee beans as they are roasting, I don't think anyone has devised a way to do that.

Hi Andy,

Yup, i have actually done that.

My heating element is connected to a contractor which is connected to a PID which has a K-type which goes in to the Roasting chamber.

The reason why i ask is because i have been looking at sonofreso roast profiles, they get their coffee out at 205 Degrees, i have done something similar and had a bit of success with unwashed coffee.

But i was wondering if sonofresco actually measures the internal bean temp or is that just the surface temp?

Thanks

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another_jim
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#4: Post by another_jim »

The only time it was done was with an implanted, thin wire TC at an ETH Zurich airroaster for a dissertation financed by Nescafe. Schenker tried to use artificial beans, but they didn't work well. He also concluded that knowing the surface temperature, air flow, and how fast the roast has gone gives a perfectly good estimate (i.e. the faster the roast, for a given device, the bigger the drop from external to internal.
Jim Schulman