Why are beans visually over cracked? See image.

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Why are beans visually over cracked? See image.

Postby normgr00 » Sun Dec 23, 2012 5:39 pm

My beans come out with extreme cracking on the ends and opening along the slit exposing the center. Why is this? My suspicions are I may be baking it or there may be to much moisture in the bean.

The resulting coffee has a good taste to my untrained pallet. Not burnt and not bitter. My wife who has better taste than me likes it but I think it could be better. The center of the bean is equally roasted as the outside. I hear the first crack right around 5:30 but can't hear the second over the iRoast 2's roaring fan.

I have a iRoast 2 and try to achieve a FC or FC+ and it has a nice color, not over done. The image below is a Nicaraguan with low chaff but I have this problem with high chaff beans too.

My roasting profile is as follows:
1) 370 - 4:30
2) 400 - 1:30
3) 375 - 1:00
4) 335 - 2:30
5) 390 - 0:30
Total roast time 10 min.
Image
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Re: Why are beans visually over cracked? See image.

Postby normgr00 » Sun Dec 23, 2012 5:52 pm

Second image
Image
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Re: Why are beans visually over cracked? See image.

Postby bigbells » Sun Dec 23, 2012 6:29 pm

What an amazing picture! They look like roasted walnut meats and they look delicious. I've never noticed that much stuff in the seams of roasted beans but my naked eye doesn't see them in that much detail.

Are those by any chance the very large Maracaturra -Finca El Naranjal? I just roasted that bean for the first time, and the color of my roast appears significantly lighter than other beans which had the same amount of weight loss after roasting.

The color looks great but the exploded ends say over-roasted. They still look really good though.

Why do you bring the heat down to 330 in stage 4 of your profile? That's the only thing I can think of that I might experiment with.

The beans sure look darker (too dark?) in the second picture. My comments above were made based on the first picture. It could well be that the different background colors are fooling my perception.
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Re: Why are beans visually over cracked? See image.

Postby UltramaticOrange » Wed Jan 09, 2013 7:25 pm

normgr00 wrote:My beans come out with extreme cracking on the ends and opening along the slit exposing the center. Why is this? My suspicions are I may be baking it or there may be to much moisture in the bean.


The beans crack at the ends due to expansion during roasting. I'm generalizing some when I say this, but the expansion is a good thing and the resulting cracks are expected and normal.
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Re: Why are beans visually over cracked? See image.

Postby JoseG » Mon Jan 28, 2013 4:36 pm

They look good to me :-)

My theory about cracking is that it depends on how much moisture you have in the bean and how quickly you bring them to first crack/City. Since I roast in a cast iron pot with a whisk my first crack lasts for 2 or 3 min. So I usually get my first crack starting at 7-8 min. and fade out at 10-12 min. At the beginning of the first crack I drop the temperature a bit so that I can stretch my roast and really caramelize the beans. So for a full city I'm usually looking at around 20 min. or so.

The last bean I had cracking in such a way was the maracaturra as well. But it tasteds great, I would worry about a thing :-)

Also, not sure about the bump back to 390 for 30 seconds. Maybe it's just to squeeze the oils out for visual satisfaction but I'm not sure it would do anything.
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Re: Why are beans visually over cracked? See image.

Postby normgr00 » Mon Jan 28, 2013 5:29 pm

Thanks for all the great comments. I have been tweaking my profiles and still the exaggerated cracks are present. I suspect it has to do with the roaster, the iRoast 2. I suspect the hot air technique brings the bean temp up faster than other roasters. Almost every kind of bean I roast does this so I don't think it is a particular kind of coffee having more moisture that causes this. The roasts are full city and full city plus so I don't think they're getting over cooked but they can roast fast. I'm now doing a complete roast in 6:30 not including the cool down cycle. It all tastes great so I'm not worried, just curious.
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