Temperature issues with Behmor 1600 plus

#1: Post by **AKucewicz** » May 26th, 2016, 6:37 pm

I bought a Behmor 1600 plus about a month ago (my first go at home roasting). I did extensive research about how the Behmor functions (I guess the plus is night and day better than pre-plus era).
I do manual on P5 (highest) mostly 1/2 lbs roasts so far. I'm noticing a serious temperature drop around the halfway mark in my roasts. I'm hitting 250 ET according to the panel at about 3 mins in, 270 at about 4 mins in, then slowly dropping to around 260/250 ET before quickly climbing back up around 7 mins. I know the roasting process fluxes between exo and endo thermic, but a drop/flatline of temp for that long (3 mins of a 11-12 min roast) seems like it's not right. Is this a voltage problem?

#2: Post by **btreichel** » May 26th, 2016, 11:33 pm

I'm guessing that's when the exhaust opens. Temp a is exhaust temp and basically says shut until about that time. Watch that next time, when it moves off of 129, you know that it's opened. For me, roasting about 300 gr, that occurs right about when the bean has dried ( yellow), it's also the time I turn the drum speed up.

#3: Post by **EggShen** » May 27th, 2016, 9:26 am

Agree with btreichel. Sounds like the afterburner, which I believe kicks in at a set time depending in what weight you're using for the roast. I always use the 1lb setting (with a 230g charge), which means it kicks in at 7:30 into the roast (10:30 on the Behmor countdown timer). For about 75 seconds, ET scoops down and then recovers. I don't know how this correlates to BT because I only have one probe, but from what I have read the BT change isn't nearly as dramatic as the ET change during this dip.

Only been roasting a few months, so caveats abound.

#4: Post by **JojoS** » May 27th, 2016, 9:42 am

I have seen roasting charts of BT of modified Behmors and they all show a consistent rise during the time the afterburner switches on. While ET will take a dip at this stage, the balancing of thermal radiation and convection heat reaching the beans at close to end of drying stage plays an important role to get an even roast.

#5: Post by **EggShen** » May 27th, 2016, 10:00 am

Thanks JojoS! Now I feel the need to mod my Behmor.

#6: Post by **JojoS** » May 27th, 2016, 10:19 am

No need to mod. Just monitor where you are in the roast when the afterburner kicks in. Tweaking by charge weight is a good way to fine tune your roast with the Behmor. When you find your sweet spot, just stick with that weight.