Uneven Roasting of Coffee Beans

Roasting on the Bullet R1
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As bab said above, it could be a mixture of varietals or maybe screen sizes. Anyway, some beans will look like that no matter what you do. And, if you’re using Yemeni coffee, as the recipe suggests, those will never be exposition material. The high-end ones are better looking, but the costs of purchasing those (90+) lots are extremely high. That being said, I’d rather have a cheaper Yemeni coffee than anything else. And mind you, the cheaper coffees are not that cheap compared to other countries. The wet-hulled Sumatran beans will also be a bit uneven if you’re roasting light. Everything looks more even when you go darker, but we don’t want the looks, we want the taste.

You can consult a couple of threads here, and also visit the Sweet Maria page with the video about the topic.

Ethiopian roasting uneven or unevenly - Roasting on the Bullet R1 - Roast World Community
Uneven roasting tips - Roasting on the Bullet R1 - Roast World Community
Why does my roast color look so uneven? Home coffee roasting issues… - Sweet Maria’s Coffee Library (sweetmarias.com)

Addendum after reading your reply, which you’ve typed while I was typing this. :smiley: To me, the 220°C PH and starting with P7, seems a bit too much for 350g. You might want to try going down a bit, as that might be causing some scorching. Yemeni coffees are all naturals and they should take the heat well, as they are very dense. Nevertheless, I’d go a bit easier with smaller batches.

One last thing. Have you seasoned your drum? I’m asking because there’s no data about that in your roasts, but you might’ve done it without connecting the Bullet. That would really cause some unevenness if you haven’t.

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Can you elaborate on what you mean by “notification alarm” ? I don’t know of any notification alarm that indicates “roast is ended”.

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The recipe you’re showing is for 350g, but, if I’m understanding correctly, you’re roasting only 100g of beans. This will likely not result in a good roast. Power, fan, and drum will need to be scaled with a change in the weight of your green bean input to get consistent results.

Two other things stand out with regards to a non-uniform appearance:

First, a light roast, ending 45 to 90 seconds after the start of first crack, will almost always look a bit uneven when compared to a bean that you’ve taken to, say, medium or dark roast levels. It’s simply the nature of the product – a shorter roast will often leave you with dimpled or wrinkled looking beans, uneven in color, and more chaff still attached to the beans. As you roast darker, the color will even out, the chaff will blow off, and the texture of the beans will smooth out (as they expand).

Second, with regards to the Yemeni beans – in particular if they’re naturally processed – those you might never get to be uniform in appearance. In my (admittedly limited) experience with Yemeni naturals, especially at a light roast, you’ll always end up with a range of shades. Delicious, yes. Beautiful, not so much.

In general, if one of your goals is to have a visually appealing, uniform pile of coffee beans, roast to medium or dark. And as a rule, if you’re trying to replicate a recipe, use the same amount of beans for which the recipe is designed.

Good luck, and let us know how your future roasts turn out!

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The “End of Roast Alert” action in the “End roast setting” step that marks the final element in a recipe. (sorry for multiple deleted posts – my ability to properly quote was momentarily on the fritz.)

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Ah… thanks for clarifying that. I don’t use the recipe function so didn’t know about it. :slight_smile:

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Hi Rafeea-

You did nothing wrong in operating the Bullet nor roasting! Ending the roast with PRS then opening the door to drop the roast about 1 second later makes for a ‘prettier’ chart. It does nothing to affect the roast.

The time between 1st crack start (I choose to abbreviate that as 1Cs) and when you drop the beans is decided by how dark you want to roast. How dark you roast is determined by

  • your personal taste preference
  • how the greens respond to roasting

I have a taste-preference for dark-roasted coffee. But not all greens respond well to being roasted to the dark stage. So I have to be careful to buy greens that are suited to a dark roast. That eliminates possibly more than 75% of the available greens (yes, I’m guessing) and of that still left, not much appeals to my taste and the way I roast.

Find your way to the Dashboard, find Users, then go thru what other users have done in roasting. I think you’ll see most folks roast pretty light. But you can review the roast profiles to see what certain varieties of greens were used for light/medium/dark roasts. It will take some digging on the internet but I see it as time well spent in ‘research’. Here’s a link to my saved roasts for a starter.

As an aside, for a dark roast of 550 gm, my roasts are over 14 minutes. I drop the roast at about 445°F which is about second crack start (2Cs) + 10-14 seconds.

Bruce

Edit- end temperatures measured by I-Temp (the IBTS) are subject to error unless the user keeps the IBTS lens clean! A dirty IBTS lens displays a lower temperature than actual. So regular maintenance is important.

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Sorry, what do you mean by seasoning my drum? I am always connecting my laptop with Bullet the moment I started roasting until the end.

Thanks for sharing the links with me. I will go them to get more idea.

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Yup, this is the one :smiley:

End of Roast Alert
End of Roast Alert2526×760 98.4 KB

Regards,
Rafeea

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Instruction manual recommends that you do a few roasts which you are to discard. These roasts leave a film on the drum interior which eliminates any metallic taste transferred from the drum to the beans during the roast.

It’s in the manual…

Bruce

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Hello Good morning @bab

Thanks for the guidance!

Roasting green beans as an overall seems requires a lot of practice with trial and error.

I’ve had a look at your roast profile and I can see you like Mexican coffee beans. Something I would love to roast in future.

For the IBTS maintenance/Cleaning it up, will will consider it and check on the internet how to achieve it.

Regards, Rafeea

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I was under impression/assuming that the uneven roasted coffee beans I’ve seen in my tries could be due to the oil residue created as a result of the beans I’ve roasted initially. However this suggests, I need to Season my Drum which means I need actually to create an oily surface on the drum to seal the steel so it does not rust. I was thinking the other day to open it up and clean it, OMG!

I missed doing this. I will start once again with these steps.

“The oils from the coffee will help seal the steel drum so that it will not rust and it will create a more smooth surface inside the drum. The drum may not be fully seasoned until 5 to 10 roasts have been completed but after 3 seasoning roasts you can drink the coffee you roast”

Thanks, Rafeea

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Thanks @jeremy much appreciated this feedback.

I will consider these while attempting my next roast.

The reason I am trying to roast light or light-medium, is that here in my country, many people like to have coffee using V60, and they usually dont go for darker roast. They prefer light or light-medium degree, if I can put it this way.

Personally speaking, I like medium-dark, and I like the extraction via espresso machine with milk.

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Just make sure you burn your seasoning roasts, without starting a fire. They must be really dark and oily. Also, the IBTS sensor will give bad readings if the drum was not seasoned, so the uneven roasts are to be expected when you don’t know the temperature. I will link you to the post where I shared a picture of my seasoning roast. Please be extra careful, as we don’t want anything catching fire. There will be tremendous amounts of smoke, so be sure the ventilation is proper, and maybe open all windows you have.

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@mohdrafeea.2zyZ further to Bruce’s link to the manual, you might find this page from Sweet Maria’s useful as it has a bunch of links. The in-depth cleaning pdf link is what helped me understand where to start when doing a deep clean.

Definitely encourage you to read the manual and the cleaning pdf to start.

Lastly, don’t consume the beans you use for the seasoning roasts. When you do the seasoning roast make sure you are in a very well ventilated area or have a ventilation system (preferably active system) to draw out the smoke from your workspace.

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Waw, the picture of the beans, that’s really really dark :smiley:

Honesty, I did not expect such seasoning step is important, and how it can influence the IBTS sensor. I will do it during the weekend and will take the necessary precautionary measurements.

Thanks. Have a good day!

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I googled it and got the following YouTube link, https://www.youtube.com/watch?v=U4H-jDGJfPI

If you have a different link, I would appreciate sharing it with me.

Noted for the ventilated area, will be careful on this part :grin:

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(DOH)!! I forgot the link: https://www.sweetmarias.com/aillio-bullet-r1-roaster.html

The YT link is useful too

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Super important. It’s similar to the necessary step of seasoning a cast iron or carbon steel pan. And you don’t ever want to clean the inside of the drum, just vacuumed the inside if needed.

As others have suggested you have to go dark to SC (second crack), preferably a little past it. You can just use cheap throw away beans, I think there are some green bean sellers who sells “seasoning beans”. I was probably a bit more extreme as I did 5 or 6 seasoning roasts using 1lb of beans each time.

I used the seasoning roast sessions to learn how to operate the roaster’s front panel and the software to manually roast (as opposed to using any recipes).

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Thank you @blacklabs for all the support and information you provided me with all roasters members here. L

et’s do this, I am excited to conduct seasoning the drum instructions. Will post my result later on.

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@mohdrafeea.2zyZ How did everything go?