Bean color

[crabloaf]

Hello,
I can’t find this topic on the forum, so if it’s a repeat please send me a link.
I currently am roasting beans in batches of 1-2 pounds in my standard kitchen oven on a convection setting. I also winnow by hand - and have noticed a wide variety of colors of the roasted beans since I see many of them still whole. My guess is it’s due to not being able to stir the beans consistently and evenly, so some are roasted much more than others. Is this true? Are there other factors I should consider?

The bean colors range from nearly black, to dark brown, to a medium reddish brown. Are the black ones burned and I should throw them out? Is there a generally better color for bringing out the best flavors?

[Ben]

Are you referring to the outside shell or the interior nib? In either case, I have never seen much (if any) color change when roasting cacao.

Can you post some pictures of what you're seeing?

[crabloaf]

This is after roasting and winnowing.  I honestly don’t know if these were the colors pre-roast, I’ve never thought to check. the beans are from Chocolate Alchemy, Guatemala Cahabon 2018.  

the darkest beans taste pretty bad- like they’re burnt. However the other color of beans don’t taste very good either. 

[Ben]

My guess is that those were the colors of the beans before roasting. You can try removing the shell on some unroasted beans to confirm one way or the other.

That being said, they could be over-roasted, too. How are you roasting? What's the end of roast bean temperature?

[crabloaf]

I’m using a normal kitchen oven on a convection bake setting. I had 2 lb on a metal tray. Roasted at 350, then at 10:30 to 325, at 12:00 bean temp (infrared read) ranged from 248-279. Turned to 275. From then until 30:00 when I removed, temps ranged from 243-273. I take 3-4 readings of beans in different areas of the tray.

[Ben]

For doing a full roast, as opposed to the initial test roast we're discussing in the other thread, I'd definitely stir them around throughout the roast. A 30 degree difference is pretty huge.

Two other things:

It's generally suggested that a roast should never stall or go down in temperature, although I'm not 100% sure why that is.

279F is a pretty dark roast. Going that high could definitely be the cause of the burnt taste.

[crabloaf]

OK lesson learned!!
The color of the beans (in my experience) seems to have no correlation to how much they've been roasted. I followed your advice in the other thread (roasting newbie question) - so roasted a small amount of beans and removed a few at 8 different time intervals. There were a few nearly black beans across the range of roasts, and also some of the reddish brown from a 10 min roast all the way to 31 min. In addition, I also winnowed some raw beans and saw the same variety.

So my follow up question...
Does mean that the color of beans is caused from/during the fermentation process? I'll have to research this more, but I'm curious if any of you have insight into this.
Thanks

[Ben]

Yep, this is probably related to the fermentation process. I'm not particularly knowledgeable about fermentation, but my first guess would be that maybe the beans were not mixed enough causing some beans to be under and/or over fermented.