Hello,
I’m using the Rob Hoos recipe and trying to do some 150g sample roasts. I am however not having much luck. Roasts are actually taking a VERY long time and I keep getting a negative ROR. Any idea as to why this might be happening? Thank you!
Well, we have no idea what the conditions were when Rob was roasting, in regard to temperature and humidity. Second, the airflow does not depend solely on the roaster, but also external factors. So, you might have a stronger airflow because of some those factors, hence f6 is too much for you or, if you want, p5 is too little for you at f6. Maybe he was using an uncalibrated fan and you’re using a calibrated one, or vice versa. I would try to find the ideal fan speed without intervening on power. Try f4 and it should be OK. Unfortunately, roasting isn’t comparable to a clean room. Even a roast that you do today, might be a bit different tomorrow. Automation might work in places with a strict climate control, where temperature, humidity and the air circulation are always the same. Of course, the consumer will never notice the slight differences present in everyday roasting, but that doesn’t mean the roasts are exactly the same. With that in mind, you should always modify recipes to suit your roasting environment.
Braca is spot on and I think there’s not much to add to that.
I can share my experience. I have roasted almost 100 batches, 200g at a time since last year and took me a while to figure out that smaller batches require less fan, less drum speed, and less interference. Even small changes to the parameters can have big impact, especially on smaller batches like 150, 200g…
To give you some ideas, I roast under a powerful kitchen hood with no accessories. Ambient temp is 19 celsius (sry, i’m in Korea), humidity is 30%, preheat temp is 200~210 celsius, F2 and D9 throughout the roast, Start at P6 or P5 and gradually lower them at 120C/165C/185C/206C and almost always get a smooth decelerating ROR. I aim for First Crack at 10~12min. End temp of 210~216C.
Also, how long are the roasts and what are the timings for yellowing, first crack, and the end temp/color? If you can share more info, we can diagnose the problem. You can begin by increasing the pre heat temp by 10 and see how it goes from there. Try changing one parameters at a time and be consistent with ambient temp and preheat temperature until you get the ideal timings for the yellowing, First Crack, eject temp.
1 Like