Preheat Temp

For those of you who stick to light roasts, what preheat temp do you charge at? I started charging at 446 and found my roasts to be too long (I am trying to keep my roasts no longer than 12 minutes). I later started charging at 455 but for some coffees this still results in too long of a roast. What preheat temps do you use to successfully produce light roast coffees under 12 minutes?

How much coffee are you looking to roast ?

Forgot to include that, thanks! 800g batches.

I’m at 572 for 900g

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Good to know. I think I will def be bumping up my heat a bit.

I’d also like to add that unless you have updated to the latest firmware and provide additional under body cooling, the bullet will loose power over the course of the roast

Assuming a 120v bullet. But since you used F for temp I assume you are stateside

Yes I am stateside. I hadn’t thought about losing power throughout the roast, in fact I assumed for some reason that the roaster would get slightly hotter over the course of multiple roasts. I think I mistakenly absorbed this from reading books addressing gas roasters and didn’t translate it to an electric roaster. Will have to look into the firmware update. Anyways, that’s a good case for starting at a higher temp. Do you find your bullet loses enough heat to justify charging at a higher temp than you normally would otherwise?

Here:

https://community.roast.world/t/900g-full-flame-test/8450/75

Cliff Note Version:

I found that on the stable firmware release, the bullet on a constant P9 would drop from 1500w to 1100 over 8 minutes.

On the beta firmware 602, The wattage would go from 1500w to 1420w over 8 minutes on P9

On beta firmware with additional underbody cooling, the bullet would draw 1500w without a wattage drop.

Interesting to see the declining power draw during the roast without a change in the power setting.

If I’m not mistaken, it ties directly to the temperature of IGBTs (the large bipolar power transistors that switch current to create the magnetic field for the induction), as shown in the roaster info display.

Past around 80C the software limits the current draw to keep the temperatures within the operating limits of the transistors, but this lowers the effective power.

Fascinating. I’m in Toronto and went with the 240V unit and had a dedicated line installed in my basement to accommodate it. I’m now using an AC infinity fan underneath as a precaution anyway since I’ve had many a laptop motherboards fry from years of heat. I just did 15 back to back 910gram roasts at 290 Celsius and it floated around 63 degrees the whole time. Didn’t think to check the Wattage though my voltage was pretty consistently 239-240.

I’ve a 120V unit and on my circuit I get 1430 W when I keep the temps under the threshold with a fan.

The line voltage sags to 105V when pulling the amount of current to make that power, which suggests a circuit with a fair bit of IR drop.

To add to @john_l 's point, If you look at the firmware revision notes, the last couple were about updating the power usage on 120v

Aillio support stated they’re pretty much running at the max capability of 120v. Which is why it doesn’t take much of an out of spec variable to reduce effectiveness.

I’m running on a dedicated outlet about 6 inches from the house mains service with a 25ft 10 gauge extension cord. My voltage holds between 118v and 115v.

I have a desk fan underneath and I usually hover around 80c. Oh the difference between 120 and 240 amp draw.

Where do you monitor this temperature?
I will keep an eye on it.

When you are in roast time, there is an circle with an “I” in the upper right hand side. Same place you would find the error logs.

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