Volume of First Crack

Hi Folks!

I have not posted in a while. Work getting in the way of Life, and all that.

I have a new theory! (which means, of course, it may be way wrong)

After I switched to the CoffeeMind recipe (230 preheat, P8 to 150 then P6 to 190, then P5 to drop) I noticed I had a very hard time hearing first crack.

I figured it was one of two things - my hearing started getting worse (not impossible for a 65 year old who did like rock and roll in his youth) or the beans were just not very “cracky”

But I didn’t like the sweet smooth flavor that a long dev time gives you, so I juiced up the roast temps. Now it is 235 PH, P8 to 155, P6 to 195, P5 to drop.

Low and behold, I can hear first crack again. (and I got a more acid, more bitter roast)

Am I crazy? Has anyone else seen this? I think I can explain it by saying the water gets hotter sooner, and bursts through the cell walls, but heck. I am no organic chemist.

You can see my recipes in my profile (CoffeeMind Standard, and CoffeeMind Running Hot) and there are a number of roasts with each.

Hope everyone is well!



I looked at two of your profiles, one running hot and one standard. They were different beans and you didn’t mark end of first crack, but my guess is that your running hot is producing a more aggressive first crack where more beans are cracking at once, amplifying the sound. I find that I can hear first and second crack better if I wear Bose noise cancelling headphones. They tend to block white noise, but let small pops and cracks through, so they cracks are more audible over the consistent sound of the drum and fans (I have a second fan pointed at the PCB).


I’ve used the noise cancelling headphones as well. They really do work.

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Brilliant! I’ve been struggling to hear FC and just figured my hearing loss was the reason - it probably is but I have Bose noise cancelling headphones and I am definitely going to give those a try before looking at stethoscopes or other “focussed amplification” systems. Thank you.

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From my experience different beans behave differently in terms of FC and SC even when I use the “same” roast plan for the two different beans. Some beans crack louder than others for sure - without any “hearing aid devices” on my part.

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Is the recipe CoffeeMind recipe based off of Morten Münchow? If so would you share his roast.world username or profile.

After just hearing about him on the Roast Rebels Podcast I am curious to take a look at his profiles. I have not been able to find his profile.



I tried the Noise Cancelling headphones and they didn’t help. I know some beans are louder/quieter than others but I’ve done three different beans and I struggled to hear anything. I picked up a stethoscope and will be giving that a try this afternoon.

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I’m stuck at your statement about long development time resulting in sweet smooth flavor. Is that a generally accepted principle? I tend to to roast with long dev times and I also do prefer sweet smooth flavor. So maybe that’s why I haven’t enjoyed other roasting strategies I’ve seen here!

Morten does a lot of experiments as well as roasts as part of his classes so you will have to sort through a lot of that.


I’ve seen some real gentle curves here and there, and hitting FC really gently can sometimes make for some quiet roasts. Takes some pressure to get these things to pop. It is debated how much that influences the flavor on its own, or what is just the by product of heat and time. Hitting FC with enough power to hear it seems to open up the beans to let the water out and help in the completion of chemical reactions in flavors, so i’d assume proper expansion to be important in flavor.


Maybe thats my problem because my next step is hearing aids! The stethoscope didn’t help at all. I am suffering from age related hearing loss (also liked power tools and things that go bang when younger:) )so I need hearing aids anyway. I am concerned that if I have hearing loss in the range that the cracking resides it might not help me with the roasting. I think you might be right about entering FC gently - I can hear the odd crack (gives me hope hearing wise) but then it just becomes muddled. I’ve been doing light roasts because I enjoy the results and I’m a fan of Ethiopian coffees which excel at light roasts (in my opinion) and I’ve been using the suggested recipe from the manual. I think I’ll try getting to FC under a little more power and see what that does. I used to roast on a Hottop which has zero insulation around the drum and both FC and SC (if ever I went there) were clearly audible.

You can always test with microwave popcorn. That would be a very loud and extreme version. But at least you’ll know if it is a frequency/tone issue or just an amplitude/volume issue.

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I can hear that - I’m going to try a bit more power/fan longer/later in the roast. I know I need hearing aids, either that or everyone has started mumbling a lot!! Thanks of your help, much appreciated.

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How is it going with heading FC?

I’ve come across a few beans where I have trouble hearing FC, and others that are difficult to get there without suddenly exploding.

Forgot to take you in my reply above.