I’m interested in hearing from other higher elevation roasters. I live above 5000 ft and first crack for me is around 194 C. Most roasts from others have first crack above 200 C. Here is my latest profile of a Costa Rica Tarrazu medium roast that has a good balance of sweetness, acidity and slight bitterness.
This is very interesting. I went to your RW page to look at the details of that particular roast. Your batch was about 1 lb (1/2 kg). I wouldn’t say your FC is terribly far off from most of us at sea level. Remember at higher altitude there is less air pressure and less moisture in the air, therefore you’re probably going to lose the moisture from the beans earlier which might explain your FC at a lower temp. Maybe consider some of the principles used for high altitude baking and cooking adjustments: Baking and Cooking at High Altitudes - BettyCrocker.com - it also mentions that gases expands faster.
I’ve never cooked/baked in high altitude so I can’t help beyond some conjecture based on science of cooking/baking that is well documented 
That said I also noticed you used F5 all the way in that roast…I think you might be drawing out too much of the hot air from the drum at F5. When I roast 1 lb, I start with F2 and only towards the very end I might go as high as F5 to draw out the chaff.
I lived in Albuquerque, NM for many years. Albuquerque is over 5000 feet above sea level.
Water boils about 12 degrees C cooler at 5,000 feet. so your first crack sounds about right. the water in the beans will create steam at a lower temperature and therefore start cracking at a lower temperature. The down side to this is that: you should need more heat to get to the same roast level that we do at sea level.
There is a canning company in northern California that reduces it’s tomato sauce under vacuum. by doing so, the tomato sauce is not getting asmuch heat and the sauce does not get caramalized or have a maillard reaction. The process still creates steam but at a lower temperature. (BTW a pressure cooker works on the opposite principal: it cooks things faster because it is under pressure)
Hmmm, this is an interesting mental exercise. What role does the remaining moisture left in the beans have on the final roast temperature?
My initial reaction would be that if you are timing your development from the start of first crack and the temperature is lower, you might want to try dropping at a higher temperature.
But, as always: What your get in your cup that you like is the best solution.
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I like the flavor of this roast. I have done darker roasts and those are good too. If I’m looking at another roast profile I would like to know where and what altitude it was done before I try to duplicate it. Some say that roasting at higher elevations produces a better cup of coffee
High Altitude Coffee Roasting: Why It's Better
Is there a way to modify shared roasts to display in Fahrenheit?
Roasting in higher elevation situations is complex, because some of the roasting involves water, and some reactions don’t so much. I think the drying phase is more altitude dependent, so mess around with that. You’ll read a ton of varying opinons about altitude, but go with what tastes right.
Drying phase has the most water, however it is possibly the least flavor influencing. But if you evaporate ate a different speed from sea level, then that will effect the rest of the roast, no?
Getting into maillard and caramelization (browning), you still have water involed. Pretty much until first crack.
Be super consistent with how you mark your color changes. get a good accurate LED for monitoring color during the roast. Buy an LED light for cinema and television. They often have adjustable color temp and much higher color accuracy. This can help a lot. Once you find the average temp for certain color stages, you can sort of cross reference temps to your calling color changes, and further make your stage marking more consistent.
THe average times for roasting are 4.5minutes for drying, and 4.5minutes for maillard into First Crack(FC) at about 9minutes. Some people extend those times byu 30 second here or there and get 10minute FC, and other may shorten those times and get 8minute FC.
So go through the steps and start analyzing your roasts:
- Low and slow dry and back up to standrd time for mailllard
- fast thru drying and back to standard for mailllard
- standard for drying and slow for maillard
- standard for drying and fast for maillard
You can further break things up into mailllard vs caramelization
If maillard is starting at Bean Temp 260F, or there abouts (green to yellow), and caremalizarion somewhere further into the yellow to browning stage, then you can mess around with speed in the maillard phase and slowing in the caremlixzaion… Or flip that. Or make a dip in between vs a straight constant RoR. They all effect the flavor, but idk which is prefered to you.
Then repeat this every time your room temp changes more than 5 degrees. as you may need to extend the drying phase in colder rooms to more evenly warm up the bean.
Hey there… I realize this conversation is from the end of 2022, but I’d love to hear what you may have learned, @keward, about roasting at your altitude. I live in Bogota, Colombia and am roasting on a Bullet here, recently started on the Bullet. It’s 8500 ft above sea level here, and I know that the recipes I’m trying are not probably going to be the same here, looking to see how best I should adjust, if you have any general ideas or lessons learned… Thanks.
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Idk if the same logic applies to the Bullet though. It is induction, so the drum heats up super fast, and the air stays cooler.
So, precisely how that translates t altitude roasting is a little different. Perhaps charging before the inside is roasted. Because the water on the out layer can evaporate before the center is heated up, and charring and tipping are fairly common.
I tried allowing preheated air to enter the intake, and that seemed to help, but then the plastic on the exhaust warped. So I had to stop doing that. It also makes the roast prone to shut down from over heating. The stupidly placed electronics next to the drum, is pretty insane.
I mostly just get grass, paper, or char. I personally don’t mind grassy though.
I’ll through out 2 of 3 roasts typically.
I didn’t write the above to trash the Bullet or anything, but I’ve tried everyone’s profiles, and I get pretty crappy results. Even the coffee mind and Coe profiles result in some what nice but ultimately weak and slightly papery flavors. There is just no way that other people are getting the results I get, and out there winning competitions or consistently enjoying their coffee. So I tend to think it is just me.And at the same time, I’d assume after 1K roasts I’d have found something I can get good results with.
I’m ok with being a crappy roaster if it is just my fault, but would also like to know if I just have a bad copy of the Bullet, or if it is an altitude thing. It seems I am the ONLY person who has issues.
Heat by conduction/radiation should be the same at altitude. Convection would be reduced. I would think you could perhaps bump fan speed proportionally to compensate.
Isn’t that just the irony though? The higher the fan speed the more heat gets sucked out? Which results in low flavor too.
There is a lot of potential with the higher fan speeds, but it just has never translated as you might expect.
F4 does ok with staying hot, and F5 is surprisingly hot too. Though F5 is a balancing act.
But even when my airflow gets to some high temps, the higher fan speeds always taste a bit lighter.
With a natural, it can be tough trying to keep the heat up, since the drum can burn the more delicate naturals, but under powering the drum causes the air temps to drop too.
So basically the Bullet is on such a fine line. But if someone has figured it out, would love to hear about what you did.
I’ll try P9 and F6 and see what happens.