# Uneven roast with chaff on Gene Cafe



## Beans

Just roasted 200g columbian and they seem to have come out uneven. Some still have abit of chaff on their backs. Is that normal?

8 mins and 20 seconds to reach 230 degrees.

Held at 230 degrees for 2 mins then put it up to 240.

First crack kicked in 2 mins later. Held it there for 1 min then reduced to 235.

Began quick cool down cycle 2 mins later.

Came out at 163g.

Here's a picture... is that considered medium roast?


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## risky

Moved to home roasters area.


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## froggystyle

Why only 200g?


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## Beans

Thought it'd be better to use a smaller batch, that way I can experiment more with the 1kg.


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## DavecUK

Beans said:


> Thought it'd be better to use a smaller batch, that way I can experiment more with the 1kg.


roast 250g, gene doesn't react well to smaller batches.


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## Beans

Ah, ok. Whats the actual reason some of the chaff didnt come off? Not enough heat?


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## DavecUK

Beans said:


> Ah, ok. Whats the actual reason some of the chaff didnt come off? Not enough heat?


I depends, can be lots of reasons, heat, some beans it's harder to get the chaff off, dont know why that is really. If the roast is light, then it does tend to stick a bit more. With the Gene, smaller batches actually allow the hot air thru the chamber more easily and hence heat retention is lower, this can lead to slight under roasting. Usually it doesn't cause unevenness. It's also a mains voltage dependent thing, lower the voltage, coler and slower the roast....smaller batches again perversely don't help.


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## Vieux Clou

Curious... 250g? The CBR-101 instructions state 226g max (8oz). OK, 25g wouldn't make much difference but on that scale 200g isn't a "small batch". I was thinking of doing 100g test batches.

I've had no difficulty blasting 200g of beans black as your hat at 240°: my main problem is managing a lighter roast. E.g. at 210°C the chaff stays pretty well glued on and the coffee looks more baked than roasted.


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## froggystyle

Getting the chaff off is tricky, even worse at 210c i find it tends to come off at temps of 230c+, but then you struggle to get the lighter roasts.

Try 250g at a higher temp but aim to hit cooling cycle at first crack, still going to have chaff in the crack of the bean though.


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## Vieux Clou

I don't mind chaff in the crack** but when it stays on the bean it looks as if the roast is uneven, so the endpoint is uncertain.

OTOH bunging the temp up to 230 with a long roast time, judging the roast by eyeball and doing an E/Stop when it's right turns the thing into a glorified popcorn machine. But it's pretty well what I was planning to do.

** hush now


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## Rob1

This is interesting. For a time I used very low temps that just dried the beans and caused them to expand, at which point the chaff would get blown off. I recently roasted some Sumatra with a high start temp and power and the chaff stuck to it and burned on, I believe due to the moisture content of the bean. If I'm right it would mean chaff can stick to a bean if the temp gets high enough to burn it on before the beans have expanded.


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## Rob1

Nope I was wrong. Roast was a little more even but first crack took forever to arrive and lasted for just as long.


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