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”…
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.