Newb needs some help - roast taking a long time and not hitting FC


I’m new to the Bullet but I’ve been roasting for several years on a Huky and homemade air roaster. I’ve tried the beginner’s receipe with 350g of Brazilian beans and both times, the roast has gone on for a long time and not hit FC. The roast tastes like charcoal!

By B-ROR looks so-so, but somehow the IBTS temp is not going high enough I think. I preheated to 220C and kept it there for 20 min.
I’m expecting FC at 209C but it’s taking forever to get there and when it does the roast has stalled out already.

Any advice?

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I’m no pro but try sticking to P7 and F2 until you hit yellow(or thereabouts).
Make changes to Power and Fan after…

People say the Bullet is different from gas roasters so there is a learning curve even for experienced roasters.

Hope it helps, cheers!

Looks like you prob hit 1C at about 9 min into the roast… should happen in the range of 190-200°C. If I’m right you’re likely having trouble hearing the sound of 1C- it’s masked by the noise of the beans crashing around in the drum. It’s a very common issue for nearly all of us.

A couple solutions to try-

  • tilt the rubber plug on the bean chute for a couple seconds at a time. The idea is to get it at an angle to reflect sounds toward your ear. Be very careful to not bump your ear against the Bullet- it’s hot and you’ll end up branded!
  • some have adapted a mechanics stethoscope so they can listen via the tryer port. Make up an adapter of appropriate size metal tube (copper plumbing from the plumbing section of Home Depot) to fit the tryer port with a silicone hose attached and the stethoscope fitted to the hose. To use it you would temporarily remove the tryer, insert the short metal tube (too long and you’ll hit the drum) and listen with what is now a ‘coffee roaster’s stethoscope’. It’s a bit of a workaround but it may offer what you need. Search here on R.W- others have already blazed the trail.
  • at least one person has used the same tube/hose fitting with a microphone and listened thru an amplier/speaker assembly. May take a few trials- I found the bandwidth of the amp I tried was insufficient to pass the snap sound of 2C (worked ok for 1C).
  • and I believe someone here used their cell phone set to speaker and help the microphone near the tryer port. Just be careful to not let the phone touch the hot metal of the roaster. Again, search here on R.W for the correct explanation.


Thanks, Bruce. I’ll try some of these suggestions, but I know when I ran the 3 seasoning roasts I could definitely hear first crack. I could even hear second crack. First crack on all three roasts were all at 209C so that’s why I was expecting first crack at the same or similar temp for these beans.

The other way I know the roast stalled out is that they never hit second crack and the beans are not shiny. They’re still medium brown.

There’s definitely a learning curve! I’ll try extending P7 longer.

The beginner’s recipe says to change to P6 at IBTS 120C doesn’t seem to work here.

Yeah, that’s a pretty light roast for having planned on 2C. Just not enough gas in the tank (stored heat) to coast thru the late stages. I’ve done that more than once, right @stuartmcknight ?!


The curves and power profile look pretty decent for a 350g roast. What doesn’t make sense at all is the roast color you’re seeing for a drop at roughly 212C.

For most Aillio users with most greens, FC starts at around 198-202 IBTS.

Is this the only variety of bean you’ve tried so far? If you’ve tried others, do you see the same tracking between color and drop temperature?

Bonus points for your username btw

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I picked this name when I started messing around with Unix and Linux… It kinda stuck with me.

I know it doesn’t make sense why my beans are this color and not black…

I’ve only used a Monsooned Malabar for seasoning besides this.

I’ll try one of the earlier suggestions to leave it at P7 a bit longer or even go up to P8 for a bit and see what happens.

If that doesn’t work, I’ll try another variety.

I didn’t have this problem with these beans roasting on my Huky. FC happened at 400F and dropped at 420F. Never an issue.

P4 and F4 at the end might be a little too much airflow to let the temperature rise. Try P4 and F3, and check your blower RPM in the info panel should be around ~~1200 give or take a little (F4).

That depends. I just cleaned my IBTS sensor and I get FC at around 205C now.

Drop at 212C would yield beans looking a lot like these (agtron 80 or the like)

Problem solved…

Thanks everyone for your help. I have to admit my beans are bit on the old side. I made a large order from Sweet Maria’s a while ago and it’s been taking me a long time to finish these. I figured the beans may have a lost water content, which is probably why they’re having a hard time reaching first crack.

I added about 80ml of water to a bowl of about 340g of green beans and let them absorb the water overnight.

The next day, I roasted with more heat, touching P9 at times. This time, the roast hit FC in a reasonable time. (Yes, I should have reduced heat before FC… I was expecting FC at 209C)

3 days later, they taste pretty decent in an espresso!


I have to deal with greens that are drying regardless how long I’ve had them- Arizona is not an easy place to store beans. And if those beans you bought are in a heated space, then they had extra dryness from heating during winter. We see less than 10% humidity here till monsoons start (if they start this year!); your winter heating in Toronto is going to do the same thing.

That said, you’re the first I’ve heard to try wetting the beans before roasting. That’s encouraging that it worked well for you. Thanks for that. I may have to sprinkle a little rain in my storage tubs!


edit- btw, I use a swamp cooler in the shop to raise humidity and take the edge off temps. Doesn’t add moisture to already dry beans but it helps with evil spirits if nothing else (ESD- electrostatic discharge)

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