Hearing first crack: rough poll…how do you listen for first crack?
Take a look at this old thread
you can always just do a search of the forums to see what comes up. There is a ton of information here.
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I use a portable PA system that I got off Amazon.
i remove the trier and push the microphone in that hole.
i took a piece of silicone tubing and tapered the end with an Exacto knife.
The speaker part of it:
Edit: I have hearing loss from working in machine shops for many years and there are some frequencies that I cannot hear. Without the ampifier, I could never hear second crack.
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I don’t find it so difficult to hear on the Aillio, really. In the past, when using the Gene Café, I used a cardboard cone from a wool mill (500g cones). A very sturdy material with a slightly conical shape. Later, I found an obstetric stethoscope at a thrift market, which turned out to be an absolutely brilliant sound conductor (not surprisingly) and much easier to position.
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I have hearing aids and I turn them up! 
I’d still love to hear some more hacks! My wife has old stethoscopes… I’m watching the readout and the bean probe shows me impending first crack. Still…
You can get a good estimate of 1st crack when you can’t head it by observing the increase of chafe visible in the window. Not perfect but a good work-around.
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I like the visual clues–watching the bean probe ROR, chaff, and knowing roughly the IBTS or bean temp range for first crack. Great ideas so far!
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Also, it is worth noting that there will be a dip in RoR as FC begins, or rather as enough beans begin to crack (so a little bit into FC), followed by a change in smell from the trier. That said, I still prefer to use my ears.
The dip is mostly noticeable if you look at both probes together (and still very tiny).
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I can hear first crack even though my hearing is not great. What helps most is to eliminate or reduce background noise.
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I will visit the Aillio booth at the SCA EXPO in Chicago this weekend. I’ll pose the question to their experts there and report on it.
Have a good time @lochbuie. I met the Aillio team, Thompson Owen (of Sweet Maria) and @bradm at the Boston one a couple years back just as things are opening after Covid (we had to show proof of negative test at the time). It was interesting to see all the various vendors.
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Awesome! We won the Coffee Shrub free passes but had to “pass” because we had already registered !! Looking forward to connecting with sweetmarias and coffeeshrub team: I get all of my green coffee from them!
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I usually wait until my IBTS is at ~370F. My first crack is usually around 390F
Hello, personally I have noticed that not all my coffees sound so strong with the first crack. I am very attentive, almost putting my ear close when I start to reach 198 degrees Celsius on the IBTS, and I avoid external noises as much as possible. I suppose it’s the heat intensity I give them at the beginning of the roasts, maybe the preheating or the density/moisture of my green beans influences it. I hope my comment is helpful to you.
IMHO, the bean does play a role. Some beans I’ve roasted really crackles at FC and others not so much.
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Turn D to 8 around 180 as 9 is too noisy. Let a couple go then mark. Watch RoR for hints of a rise too as that foreshadows 1C. My roasts hit 1C usually around 185C.
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Did I miss it above? Several years ago I went to a COSTCO with a Hearing Center. I was shocked to find I had sufficient hearing loss to warrant hearing aids. I bought a pair and now, with normal hearing thanks to my hearing aids I can hear 1Cs just fine. 5 years later I got tested again and learned I needed a ‘tune up’… the tech re-programmed the hearing aids by adjusting the profile. I’m a believer! There’s also a side benefit: I no longer irritate she-who-must-be-obeyed by asking ‘You say something?’ [ Yeah, I was a Rumpole of the Bailey fan in the mid-'70s. ]
ICs is really pretty easy to pick out. 2Cs? Not so much! I have to tilt the bean chute plug to pick that out of the bean-crashing noise in the drum. Of course most here don’t have to deal with 2Cs.
Bruce
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Me Too 
!!!
This is an interesting hack! I tried it yesterday and it did help! I had to drop to D4 to get things quiet, but I only did it for a few seconds. I think we all agree that we know when to get sensitive to first crack–the bean probe ROR, the bean temp range–but even the Bullet rep at the SCAEXPO was stumped.
I turn my aids “up” to increase the detected volume, but the noise of the beans in the drum gets louder also!