Low power issue


#1

I am having an issue recently with what seems to be insufficient power. I just did a 350g roast, starting at power 6, fan 1, then increasing the power to 7 or 8 to get the beans up to 300 degrees on the IRBT readout in about 3 minutes. Rate of rise is about 30 just before 300 degrees. What then happens is that from 300 degrees to about 390 degrees, I have to keep the power at 9 and fan at 1 just to keep the ROR over 20. The ROR starts to fall as the temperature increases above 300 even though the roaster is at maximum power and minimum fan. By the time the roast approaches first crack the ROR will have fallen to 20 or under at power 9. IT will then jump up as the roast approaches first crack and beyond and I can then cut power/increase fan to control the roast. On a bigger, 700g batch, once the roast hit 300 degrees the ROR started falling at maximum power, minimum fan, I could not keep it above 20, so it dropped quickly from 30 to around 20 until right before first crack.

One thing I noticed is that there is a fan (internal cooling?) that was running non-stop. I do not think this is the same fan as the fan controlling the roast because I could impact the ROR by adjusting fan speed.

Any ideas?


#2

You don’t mention your preheat temperature. If you don’t start your roast at the right temperature, it won’t progress as expected.

Just a thought.


#3

It would be really helpful if you could connect RoasTime and take a screenshot of the roast profile.
Also as @celticcupcoffee mentioned, the preheat temperature is very important.


#4

Sound like normal roasting behavior to me. The RoR will always decrease as a roast nears its terminal temperature. I usually try to peak at around 35F then finish the roast around 5F


#5

I solved this. First, I ran the process to recalibrate the fan. Second, I was not waiting long enough on the preheat phase. I was charging around 230 degrees BT. By raising the preheat slightly and waiting for about 25 minutes, the BT went up to 300 degrees and this provided more momentum for the roast. I did not wait until the roaster said “Charge”. Do you have to wait for this or is there some way to determine when to load the beans?


#6

@prust - I’ve done it both ways (wait for “Charge” and not wait). Also monitored and tested the timeframes in this post Charge timeframes. There are other useful/pertinent thoughts in that same overall thread from members here on that subject.

For me, it comes down to not knowing the specific internal design and decision points within the Bullet as to when the “Charge” statement is enabled. Using a 437F Preheat for 1lb batches, I’ve roasted as early as 11-12mins without waiting for the “Charge” statement, and also waited the full 21mins for it to be announced. I can’t say that I could tell any difference in roast performance between the two scenarios.

However, other drum roaster designs require a good 20-30 minutes for the initial Preheat to bring everything into what is considered operational temperatures. That same thing could certainly apply to the Bullet. So, because I don’t know if preempting the “Charge” statement introduces a problem(s) that I haven’t proven, I’ve decided to just allow the Bullet to contently announce “Charge”. I’m usually doing other roasting-related things (selecting what to roast, weighing the batches, etc) while waiting for “Charge” and don’t really notice the wait anyway. :nerd_face: