Problem: Interior Scorching?

an3_bolt

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Oct 27, 2012
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Having a small problem with a Brazil Daterra that appears to be interior scorching. I have conducted trials with an extended 1st stage out to 6 mins, a slower profile to FC, high and low charge temperatures and lower end of roast temp - but still having trouble. Even considered it as a cooling problem at end of roast and used an extra fan to knock it down even more quickly - no effect.

It appears in the cupping sometimes as an "ashy" taste as if it is over roasted or scorched with a too high a charge temp. But the outside of the bean looks pretty good - even roast, generally no tipping, rounded edges, no external scorching and a good development to the "flat side".

I am roasting on a older 2kg Has Garanti (drum roaster) - it has no adjustment for airflow.

The profile I am using and previously had some success with and generally seems to work:

Charge: 155C (311F)
End of Dry: 150C (300F) @ 5-5:30
First Crack: 203C (397F) @ 9:30
End of Roast: 218C (425F) @ 13:00

I have been going easy on the heat slowly ramping it up after 2:30 reaching max after the reaching yellow (150C/300F) Reducing heat from 1:30 prior to FC and maintaing an even gradient with low gas from FC to drop.

I am occasionally getting the same effect with a Brazil Cerrado.

Coming towards wits end - tried a whole matrix or solutions and variations - I am convinced it is "operator error" and there has to be an easy solution to consistently get a good result on the Brazil.

Any suggestions?

IMG_1184.jpg
 

eldub

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Mar 28, 2012
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The brazils I've roasted have been softer beans. You are probably scorching the exterior, not the interior. (Even if you can't see it, you can taste it.) My guess is that your air temps are too high at the end of the roast. There should be no ashy taste with a bean roasted to only 425*. I'd shoot for a 15 minute roast.

Do you have an air temp gauge in the roaster? If so, you should never have to get the air in the roaster above 400-415*. Your charge temp doesn't seem high to me. How far does the temp drop after you put the beans in the barrel?
 

an3_bolt

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Oct 27, 2012
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Thanks for the reply.

After charging turnaround is around 150f.

The max ET is around 410-415f.

Definately no scorching on th outside - just about looks perfect! And it is only the brazils - Sumatrans etc still coming out fine with a ramp to FC at 9:30 and finishing prior to SC around 13:00.

Will try a longer softer approach today and see what i get!

Thanks again.
 
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