I’ve been roasting for slightly less than 3 months now and I’ve only just started to roast Ethiopian Sidamo recently. I realised that the fruity notes are not that pronounced. Charge temp at 235 deg C and charge weight was 650g. I realised that there are also some slight scorching on the beans. I’ve roasted at 250 deg C before and the scorch marks were more pronounced.
I’ve been using @bradm 's roast profile for Ethiopian SDM as a gauge and I realised that my I-ROR peaks lower than his despite using the same pre-heat settings. I’m staying in the south east asia region and my room temperature is consistently at around 25-27 deg celsius. And as you can tell, there was a bit of a stall in my ROR despite lowering the power. Any advice/tips would be gr8!
Do you know for sure that this specific coffee is supposed to have pronounced fruity notes? I checked your profile but don’t see any specific information on the coffee. Some coffees will naturally have more fruity notes than others. I’ve noticed the most fruit coming from natural and honey processed coffees.
You may try a bit longer development time as this one seems quite short (considering the roast seems to have ended before the recording finished). You could also try a higher general fan setting if you’re in a humid environment to remove moisture more quickly. Trying changing one variable at a time until you get the flavor you’re looking for. Keep in mind that the specific coffee you have may not be what you’re looking for.
Not sure which of my profiles you were following, but the first thing to check is the charge weight. I roasted 325g batches for a long time before finally moving up to ~640g. Since your roast followed mine fairly closely, I suspect we did use similar batch sizes.
I used to preheat the 325g batches for exactly 15 min, but now with the larger 640g batches I preheat for exactly 20 min, starting from a cold roaster. Could that be why our roasts don’t match exactly?
I’ve found that dropping the drum speed down to D5 really transfers a lot of heat into the beans, which can lead to scorching. You could experiment with a shorter D5 interval at the start of your roast, or even just starting at D7. Use the tryer around the yellow mark to check for early scorching, per Rob’s advice.
I’ve also found that the larger 640g batches are more tolerant of fan speed increases, especially with lower drum speeds that don’t loft the beans into the air as aggressively. The RoR toward the end of your roast seems a little high, so you could try moving to D9 and/or increasing fan speed a little earlier.
Overall your curves and weight loss look reasonable, so I hope a couple of small tweaks get you the results you’re after.
Thank you for the advice! I’ve been following one of your older profiles from 2021 if I’m not mistaken. I’ve went back to the drawing board yesterday and roasted two small batches (150g) of the same bean and they look way better! I realised the slower drum speed may be the cause of scorching in my case but I’ll experiment further to confirm this.
Really appreciate your help towards teaching aspiring roasters!
Definitely some great notes in this thread. I’ve been messing around with a natural Sidamo as well and have gotten some good earthy and cocoa notes on the back end. But to be honest, I’ve become a little frustrated with trying to get those fruity notes as well that they are supposed to have.
Generally the fruitiest notes are going to come into play in lighter roasts, while the cocoa/chocolate notes will be more pronounced as the roast gets darker. For more fruit it’s worth trying a quicker/lighter roast. However, it all depends on the coffee itself. Natural processed coffee will generally have more fruit flavors than a washed version of the same coffee.
To counter the scorching I would start with a higher drum speed.
As for flavour, your yellowing is a little drawn out. I would also start dropping your temp a little early and keep consistently dropping this to slow the ROR towards the end of your roast.
Finish temp and time look fine, just how you are getting there. Good luck!
A bit of a late reply, but would love to hear how it has been going!
I definitely get more tart and grassy notes from the bullet, and often very low flavor. So I have to use very high sugar and fresh well kept beans if I want sweetness or fruit.
However, I also find there is a threshold, where I feel like some beans are just too good for the bullet, so I don’t mess too much with anything crazy expensive.
But yeah, good fresh beans roasted pretty much any which way end up being nicer than Starbucks, but it is really difficult to push into really nice roasts. Unless my roaster is just a bad sample, or my environment or elevation is challenging for conductive heat transfer. Idk. I’ve hated the Bullet since I started but read so many glowing reviews and testimonials that I keep thinking the issue is me. And I just can’t figure it out or something.
Yeah, I read the flavor notes when I buy a coffee, but then when I roast it is always pretty different. Do I get nice coffee? Yes. I get nice roasts, but never what I am going for. Always a bit lower flavor, difficult texture or mouthfeel. Less sweetness. Char or baked. It is a constant battle if you are used to have plenty of convective control.
Hope you found a way! And if so, please share! Thank you!
I’m in agreement with adamcrema – your yellowing phase is a little drawn out.
At the same time (and I know this sounds contradictory) I think you’re hitting these beans a little too hot off-the-rip. Ethiopian beans are not all that dense (in my experience), so hitting them hot at the start causes the outside of the beans to scorch a bit since conductivity in these beans is lower.
I would shift more time from yellowing to the caramelization phase. Development should be shorter for lighter roasts, as you accent your fruity notes in the previous phases.
Please keep us updated on how your Ethiopian roasting progresses!
A higher preheat temperature is going to lead to a shorter time to yellow. Higher drum speed will help prevent scorching. Fruitier flavors are going to generally come out of coffees that are roasted on the lighter end of the spectrum.
Higher drum speeds result in higher heat transfer via convection rather than conduction. As this is a far more efficient mode of heat transfer to the beans, it speeds up the roast and reduces roast time.
Keeping all other variables constant, higher drum speeds will reduce roast time. I have tried it and the difference in roast time is material.
