POLL: What temp is YOUR 1st & 2nd crack on the bullet?

Pick the closest to your temp with regards to the START of 1st or 2nd. (Temps in F)

1st Crack Temp

  • 350
  • 355
  • 360
  • 365
  • 370
  • 375
  • 380
  • 385
  • 390
  • 395
  • 400

0 voters

2nd Crack Temp

  • 410
  • 415
  • 420
  • 425
  • 430
  • 435
  • 440
  • 445
  • 450
  • 455

0 voters


What drives this poll is the quest for an understanding of 1st crack average on the bullet and its sensors. The more you google 1st crack temp, the more answers you get. Take for example, Sweet Marias lists the 1st crack and second at exactly 20 degrees HIGHER than I get. I know beans vary and roasters sensors vary. BUT, 20 degrees is pretty huge.

I roast to sight, sound, smell, smoke, and temp. Just always looking to further my technical understanding and help the community out at the same time.


Just wondering if what your found for SM numbers if those were FC and SC for the Bullet or from the big commercial roaster?

Not sure, but it was on the Roasted Coffee Color Card at the top…

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First crack temp is consistently 211 C (412 F) on IBTS over 150+ roasts. I’m surprised that this is outside your poll options. This is on a V1.5 roaster when the IBTS system was first introduced.

I don’t know what second crack temps look like.


That’s REALLY high… Hmm. A simple google of “1st crack temp” results in 385. Only Sweet Marias lists anything a lot higher, and yours is much higher than everyone else’s. Wonder if there’s a sensor issue going on?

My FC point averages 398-401F depending on the bean, usually around 398F


Same! I am on it at 390 listening until I hear the magic pop, pop, pop moment. My issue is one of when does it really end?!?!?!?!!?!?

I guess it probably does finally stop but from what I’ve seen 2Ce can just trail off. I’ve even heard a 1C pop as 2Cs begins. And coffee still tastes good. So marking 1Ce is more a discipline related to finishing the graph data. By the time the roast gets to about 426°F I’m bored enough I mark it (fully expecting one more pop as a farewell salute!).


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Yea I’m in US and use metric. I was thinking there would be more responses if metric was used it was a pain in the but to answer the question.

Also I’m thinking altitude of the roaster would shed a little light on things too


If you split the average difference between 390F and 395F, the average would be 392F or 200C.

Altitude would be helpful if there is a way to correlate the altitude to the FC temp.

Would also be interesting to know who chose their FC temp by IBTS or Bean Probe

Maybe I’ll do an Imperial vs Metric thread someday.

I too use metric and don’t have the patience to convert to F.

Somewhat bean dependent, FC @ IBTS 200-205, 2C @ ~220 if I hear it at all.

I think ambient temp is just as important as altitude. I roast small batches, usually 227g,and ambient plays a big role in how they progress.

Looking at other users roasts has been frustrating for lack of disciplined data, so I’ve pretty much stopped using them for any serious research. I assume this poll is because of the same?


looking at other’s roasts is full of frustration, especially on a one by one basis. In another thread i’m testing out other users’ recipes and results are pretty dramatically different at times. Being able to work with larger data pools to get a better sense of where things are. Like being able to choose roasts done with 120v in ambient temps between 21C-28C would be better than even getting a celebrity roaster recipe.

It won’t be perfect, but at i believe working off of greater averages are better benchmarks to learn and improve.

Would also be interesting if we could sort data by whether the forms are complete or not.

part if what makes data difficult is not having the option to share what we upload to Aillio. Some people run a small craft roasting business and don’t want every single roast to go towards machine learning and so they find ways to keep their work offline or obscured. In my mind those people would have to have discipline to be able to do that, so what we get instead are less innovative people that don’t really care. Because Aillio is dead set on getting all your data or none of it. wish there was a middle ground.