How to tell the End of FC and the beginning of SC


Just finished my 3rd and 4th batch, is there any technical or a way of knowing when FC has completed. At the moment am just guess.

When I used my Gena cafe I could easily tell by hearing less popping sound.

Or I am not just not letting the FC run enough to finish?

In the Bullet it can be difficult to hear because of the sounds of the roaster. If you search the forum there are a couple of threads that showed some creative hacks to hear FC and SC.

I’ve used temps to assist me to start “looking” for the sound and I take the trier out and try to hear it.

What @blacklabs said. It’s a challenge to hear without a notch filter and even then it’s probably going to include distracting roasting sounds as well.

What follows are a few things I have done in an effort to be consistent as an operator and to get roasts to replicate. You’ll create your own set of guidelines but I’ll share these as a starter set to discard when you get more familiar with the Bullet…

I dutifully record the 1Ce event but it’s a WAG when to click the mouse with the beans I’ve been roasting for the last year- seems to drag on and on with ‘just one more crack’ nearly into 2Cs. Makes no sense so I blame variety & processing as culprits. Using a consistent temp without benefit of sound confirmation seems like cheating but that’s what I do.

And I wonder if I even care about 1Ce: it is what it is. 1Cs & 2Cs, however, seem to be a legitimate milestone events which flag flavor changes when not replicated accurately. So that’s where I put the effort to get it right.

Similarly YP is way too subjective for my taste. If I could put everything on hold while I studied comparative photos with precise light control I might feel a little better about marking the event. That’s not going to happen. So my alternate is to always use the same temp to mark YP (IBTS = 330°F). Variations in shop ambient probably make a fixed temp reading a flawed approach but it works better than ‘is that yellow point? maybe a little more!’. And as always, YMMV.

And I’ll share something I got from @stuartmcknight about marking 1Cs- don’t anxiously pounce on the first pop you hear as being 1Cs as there can be a few outliers. He suggested I wait till I’ve heard maybe 3. That has turned out to be a great suggestion. And I can confirm better consistency in time/temp when I look at several roasts stacked in the R.W Roast Analyzer.


Full City = FC = 1st Crack. That ambiguity feels like an annoying bump in the road. So for my purposes-
FC = Full City
1C = 1st crack
2C = 2nd crack


What a helpful post! I recently asked the same question prompted by working on the CoffeeMind course, where you go “full flame” to SC. Even though I have >130 roasts on my Bullet, I couldn’t discern end of FC or beginning of SC. In my defense, I typically roast light, and never get to SC, but it was still very disheartening! I only used a natural Ethiopian for the exercise, and at least partially blamed the variety. Parenthetically, I also call YP at 165.
Thanks for the insight Bruce. That makes me feel slightly less incompetent, and much better!

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Ethiopian beans is a bit more difficult with trying to hear the pops, they are more subtle than say a Columbian. When I hear a couple of pops in relatively close succession with Ethiopian I just mark that 1C and then sometimes gauge the development by temp at that point on.


That was my impression. But far more difficult (actually impossible) for me is any hint of change in frequency or sound quality from FC to SC. At least with the current Ethiopian.
Thanks blacklabs.

Someone from another community seem to have cracked the problem. He uses a microphone inserted on the wooden bean checker ‘If that’s what it’s called’.

The microphone is than connected to an amplified speaker making it easier to hear the cracks sound.

Since finding this, I have order myself an external sound card condenser mic which can than connect to the computer. Theoretical I should be able to use this to view the spikes on a sound graph or simply connect to to a speak and listen.

Lots of those hacks to hear 1C and 2C discussed in this thread here too… search is your friend on this forum :slight_smile:

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I read the article and then implemented it myself. It works great and I have no difficulty distinguishing the cracks.