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This was particular for that coffee. A generic approach for washed central american coffee would typically be around 45-60s slower and probably +5f hotter.
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This was aimed at high floral and juicy notes. Mouthfeel would be silky. More post FC development or total roast time could increase body and perceived sweetness but would probably be less pronounced florality.
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There are many! I’m really excited about Colombian coffee these days. Emerging varieties like aidra, pink bourbon and others that high quality producers are shipping now are offering exceptional cup quality across a range of processing methods. I just cupped an arrival sample of washed Bourbon Aji from Ildefonso Cordoba that tasted like a washed Ethiopia.
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That’s crazy, it is amazing what producers are doing with agriculture and processing.
Thank you.
i haven’t been able to experiment in this way, at all, and really appreciate you sharing, as there was no way I would have thought up this approach, or even pursued a fix for my roaster. I just thought P9 was kind of off limits for us 120v users.
I’m at a little higher altitude, nothing crazy, but enough that I’m curious to see how things go.
how does higher elevation affect coffee roasting?
It affects water, and water is in so many things, including coffee beans.
It doesn’t effect roasting, in a sense, since “roasting” is kind of happening after the water has mostly evaporated, but it does effect the way the water bakes off the beans earlier on. In theory, one should go slower and at a lower temp during the drying phase, but we’re talking a few degrees and maybe 30secs to a minute at most. But Rob Hoos seems to indicate that the drying phase is not going to have a huge effect on the roast, so long as it is relatively even. As far as classic coffee flavor changes go anyway.
There are documented studies (albiet almost anecdotal) that show higher altitudes roast darker given the same profile. My assumption is that the drying phase is done a few degrees earlier, which can be 30seconds earlier depending on the RoR and altitude. So if you are cooking something in water vs roasting it, there would be some difference, but is kind of mind numbing trying to figure it all out. Would likely have to roasting in a compression chamber to get definitive results about the try differences.
I’ve read that others like roasting at higher altitudes, because in theory you can stay at lower temps, but I’ve not seen that FC is different. I crack at around the same IBTS as everyone else (see the FC thread).
There is a Colorado based roaster that claims they can roast faster than sea level, not sure what they mean, but it sounds cool.
On a “molecular” level, if your water is hotter during the drying phase, you should be cooking the beans faster in the water, and getting different chemical reactions. So, sea level and altitude are going to do marginally different things earlier in the roast, but development is pretty much the same stuff.
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right on thank you for the thorough explanation! I guess Ill roast and repeat what tastes good and improve on the others
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Some interesting reading here on roasting at elevation: Sampling Sample Roasters – Christopher Feran
(long post, search for “elevation”)
(TLDR: He found that roasting at elevation took more heat because the air is less dense, so contains less energy, at least in the context of a convection-only roaster.)
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That’s a wonderfully long writing. Thanks!
thanks a lot for the insides and sharing your recipe!
How would you slow down the roast?
kind regards,
lotana
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Roasts came out superbly.
Took me to about the 3rd one to get a hang of that FC, but they all came out tasting pretty great!
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Hi @veloandy,
Thank you again for all your help.
If not asking too much, would you be able to share a profile for a generic approach for washed central american coffee and how you would effectively slow it by around 45-60s ?
When I try to roast slower, I usually end up running out of steam at the end of the roast so would love to learn how you achieve a slower roast without compromising other variables.
Can’t thank you enough for what you have shared already.
Kind regards
Gaby
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Thanks for sharing Andy. I tried the recipe with an Ethiopian natural in a 29 degC room in Houston. It blew through the roast in <8 mins. Probably should have been gentler with the natural.
One thing that might be hard to calibrate is the exhaust fan. Mine is extremely light, just enough to draw smoke away.
Have you found challenges with that during competition roasting?
Feran is an exceptional writer. He packs in quality information in as well. Highly recommended read. I think his theory has merit. The point about less moisture at elevation is relevant as well. I think it’s true that less humidity requires less energy. I also think it’s true less air mass means less energy transfer through the hot air (less molecules of heat). I too have recently moved from sea level to 3000ft, so I’ve been interested in how coffee roasts differently here too. For our small bullet, in my few months of experience, environmental temps continue to be the largest factor effecting roasting times and energy needs.
Regarding slower roasts and s. & c. american coffees - I’d both decrease heat initially such that my dry end point was +30seconds longer. (P8 might work but might need that and -10f charge temp). I’d simultaneously keep the power settings higher later into the roast, so there is more momentum through FC to the end of the roast. Ethiopian coffees can be roasted very light without underdeveloped flavors in a way that american coffees usually cant be.
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Yeah I’d recommend higher fan speeds, especially to assist removal of more chaff on natural coffees.
Have you done the fan calibration routine? In theory, that should make the fan speeds more equal. (I assume the demo V2 unit I was using had this done - I’m assuming now that this is a built in feature they are built and calibrated at the factory, but probably doesn’t hurt to recalibrate with your local environment.)
And yes! During competition, part of your calculations as a roaster are taking ALL the inputs into consideration. The best you can do is use the practice time they give you and use your roast data to confirm your settings or change them. When I practiced with the Giesen W6A, I intentionally did a number of batches with air and drum adjustments to see how much range I had while still getting ok cup results.
Yeah good point on the internal fan, I haven’t done a recent calibration. Probably good to do post cleaning. I’ve also done some of the cig-lighter calibrations that Rao has mentioned.
My previous question was more related to an inline exhaust that is external to the Bullet. Like one used to pull smoke away from the roaster and dispersed outside. These seem to be a loose variable.
Exhaust fan - really good point. For the shared roast, it was exhausting into the atmosphere.
My setup at home, I have about a 4" gap between the roaster and my duct, with a cloudline fan running near max speed. To me, this has 2 advantages and a downside: 1. more ambient air lets the exhaust be cooler, and less inline fan wear due to heat. 2. no cooling fan or ducting pressures effecting the roaster airflow. The downside is I don’t get 100% of the smoke vented out, but I didn’t find that to be the case even with an adapter + duct attached directly either.
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Thanks Andy 
Yeah, I kind of miss the old back porch late spring still day. Flowers and bees. exhaust venting into open air and drifting away slowly. Roasting 250grams, so no real smoke. Good times!