Speaker/sound feature

I know I mentioned this somewhere but thought I would mention it again. A speaker or some way to amplify the sounds from the roasting chamber is really needed. There is no way to hear (for me) first crack let alone second with the general roaster sounds and a exhaust fan running. I know Jacob is lounging in Taiwan drinking siphon all day and probably has nothing else on his list but this feature would make life so much better.

Hey Jacob…enjoy the siphon and look forward to the sound export. Thanks.


Hearing 1st crack is truly a challenge… made even more difficult with small beans and/or many naturally processed beans… at least for me… Couple of ideas:

  1. For me the tryer is nothing more than a good way to prop open the door of the Bullet… it’s not big enough to take samples for tasting purposes, and the window gives me just as good a look at the beans as the tryer. So why not build a substitute for the tryer that is really a temperature resistant microphone? The sound could be listened to, or even better, the signal from the microphone could be traced on the roast graph… a level signal of background noise would be present pre-crack, then spikes in the track could be seen as “pops” are “heard” (detected) by the microphone. We could “see” 1st crack rather than depending on “hearing” it. I can dream it, but lack the knowledge, expertise, and engineering ability to design it. Ha Ha.
  2. Another option might be a “stethoscope” type attachment that could be stuck to the front of the roaster. I might try to borrow a stethoscope from someone to see if this works… or deafens me.
  3. Back to the microphone idea… could a temperature resistant microphone be added to or shaped to substitute for the bean charging plug? Maybe even a bluetooth microphone that would transmit a chart (trace) back to my phone… we could then look for sound spikes, and those would definitely be “pops” from 1st cracks.

Love the roaster! Way better than what I used before. Love the software. Just trying to help make it better…


That would truly be phenomenal. I have tried putting my ear to the tryer (cheap stethoscope) and have tried listening briefly with the tryer removed. Too much background noise in the drum to hear it. I think the link visually to the software would be amazing.

This article on CoffeeNavigated mentions a couple of listening devices. The “earmuffs with a tube” reminded me of the Tom and Ray Maggliozzi trick of using a length of garden hose for locating the source of weird noises in your car. May be worth a try.

I recently bought a cart in order to store & operate the Bullet. Unfortunately the cart is a little high so I ended up with my ears about the same level as the bottom of the roaster door. I didn’t think a lot about it until the 3rd or 4th roast when I realized I’d been able to better pick up the sound of both 1st & 2nd crack without giving it any conscious thought. No guess work- just a clearly discernible sound amidst the noise.

So, just for the hell of it, and before anyone gets launched on a development program to isolate and amplify the sound of 1st/2nd crack amidst the sound of crashing beans, just try a low chair or stool so your ear is lower than usual. You might get a nice surprise.

Couple of afterthoughts-

  • I wear hearing aids. They seem to be calibrated to amplify the sound of the bean movement, but they may also be beneficial in capturing the sound of 1st/2nd crack.

  • Getting my head lower leaves my ear about the level of the gap at the bottom of the door. Perhaps that’s the source of the clearer sound of the crack.


This works really well for me. Insert into trier.


Excellent… a stethoscope. And if you wear hearing aids as I do it becomes ‘an electronic listening device’! :slight_smile:

  1. Funnel
  2. 1/2 inch flexible tubing. Like for water fountains
  3. 1/2 metal adapter to plug into trier. Silicone tape to secure
  4. (Optional) a 90 degree 1/2 elbow adapter. It works fine without this as long as the flexible tubing can bend.

You can’t miss first crack with this.

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Love these home-inventions, especially this one because I too have hearing loss. I can hear 1st C most of the time from the Bullet, but can’t detect the first few snaps of 2ndC. I can hear 2ndC once it is rolling, but that is a darker roast than I prefer. I tried my cheap automobile steth-tool for listening to auto noises where you touch the probe to an exterior surface. But, it was useless on the Bullet. I was picking up all of the machine noises and cracks were also being drowned-out by normal bean tumbling noise.

I’ll be trying out that funnel invention on my next roast. Thanks for the photo and idea pnrenton!

An additional help with the funnel is to use earplugs. I have used Earasers ( www.earasers.net) or on Amazon. They filter out a lot of the background noise but not significantly the sound frequencies of bean cracks.

I took my cheapie mechanics stethoscope and modified it in a similar fashion to your creation. I can flick my fingernails together (near the open end) and hear pretty good through this thing. I haven’t tested it on a roast for cracks because I need to consume what I have on hand. But, am looking forward to seeing if it helps.

I know that my “Bean-O-Scope” would not tolerate any extended exposure to heat, but that would not be how I’d use it. I’ll use it for very quick sound sampling by inserting it into the Trier no further than the existing end of the Trier. That way, I avoid coming into contact with the drum and simply tune-in for a few seconds to hopefully see (hear) whats poppin’.

I’ll likely modify this to make it better after testing it out and thank-you for sharing the original idea. :clap:

For an interesting take on roasting sounds, take a look at RoastLearner. It appears to be a proof of concept on using machine learning to train the computer to detect first crack. There’s a video on YouTube that shows the software in action in Artisan.

Interesting idea and the person claims to be using a cheap $10 USB microphone to capture the sound (externally). Does look to be a WIP right now and worth watching to see where it goes. I would lack the programming ability to do something like that on my own. So, for now I’ll hafta stick with the “hearing aid” human factor method. :nerd_face:

Nothing wrong with hearing aids regardless the technology… even a piece of hose! :sunglasses:

Finally needed to roast a couple of 1lb batches today and test out my “Bean-O-Scope” version 2. Bottom-line, this thing absolutely works and I have hearing loss in both ears (Tinnitus). I did modify my first design to make this one easier to use. I added a stainless steel barb-fitting (sourced from Amazon) which is 1/4" on one end and 3/8" on the opposite end.

This barb addition allowed me to connect the 1/4" end to the red hose of my cheap stethoscope. But, before sliding that red hose onto the barb, I slipped a washer in-between the red hose and the middle of the barb. The hose is a tight fit and holds the washer snugly in place against the middle step-up to the 3/8" barb.

The beauty of this barb’s 3/8"-end is with the washer mounted to it as a “stop”, the barb is prevented from going any further than flush with the inside of the Trier tube. The large washer also helps reduce heat loss while I’m “tuning-in” to snaps through the Trier tube.

1st C wasn’t really hard to hear with the Bullet via just my hearing. But with this tool in use, I can listen-in and know exactly when the beans (collectively) are starting to crack. For 2nd C snaps, this thing is a “god-send”. I insert this right before when 2nd C begins and can hear every individual snap of 2nd. I like to stop my roast level a few seconds after 2nd C begins. So, this allows me to know exactly when 2nd C started and prevents me from allowing the roast to extend too far into 2nd.

The end of the tool that I hold into the Trier tube does not get hot in use, even when I’m holding there for 30 seconds or so. For 1st C, I tend to just jump-in for a few seconds at a time and if no cracking sounds, I pop the Trier back in. But for 2nd C, I hold it in-place for upwards of a minute so that I can hear the first snaps of 2nd. Love this thing because it works and is easy to use.

PS: I’m now a “coffee-doctor”…:sunglasses:

Edit/Correction: I mistakenly posted the larger barb end was 3/4" and it is 3/8". That’s an important difference to correct because 3/4" would be too big for the Trier tube.


Very smart!

What ones work best?

after rereading all the posts, i thought i would update my posting. i too turned a stethoscope into a crack device but i put a small copper tube probably 1/8th inch into the stethoscope tube and drilled a similar hole into a cork. now the tryer hole is sealed and i can listen for the cracks. word of caution if both ears are connected…you wont hear the alarm.

After just over 2yrs with my “Bean-O-Scope” ver 2, I’m still using it every time I roast on the Bullet. Nothing has broken or worn out in all that time. I wear it around my neck (like I’ve seen doctors do) and it is at the ready for a quick check.

The neatest thing about using a device such as the ones in this thread is hearing things that (I think) you would not typically hear. One example is the very faint lead-up sounds to 1st and 2nd Crack. There are very faint sounds for a good minute before the larger, more distinct sounds arrive from 1st and 2nd Crack. I have never heard those faint lead-up sounds from outside of the roaster (and never would).

Most of us have had a varietal bean whose Cracks are not loud enough to be heard outside the roaster. These devices really help with that challenge. I also use the Trier to check the bean’s exterior smoothness as it develops during the process of going from 1st to 2nd C. The temps on our roasting graphs are also a good tool for seeing when 1st and 2nd C are approaching. There is typically a slight tick upward in Bean Temp just ahead of the Cracks. These things, coupled with my Scope and I always know where the beans are in regard to the Cracks. :sunglasses:

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Here is what I’ve settled with and very clear to identify if it is an outlier or not