There is a fantastic starting recipe in the manual. It’s become my baseline.
V2 Roast Recipe Example: 350g
The following roast should finish in about 10 minutes or less. Roast Level: Light
Weight: 350 grams
Preheat: 220oC
Charge Settings: Power 7, Fan 2, Drum 9 Infrared Bean Temp@120oC: Power 6, Fan 3 Infrared Bean Temp@165oC: Power 5 Infrared Bean Temp@190oC: Power 4 Infrared Bean Temp@200oC: Fan 4
<First Crack Begins@196–204oC >
45–90 seconds after First Crack: End the Roast
Hey Graham!
There’s lots of good stuff in this thread. How’s the progress been since the original roast?
If you’re still struggling I’d first absolutely get rid of the soak, second, try keeping f2 or f3 till the beans just start to yellow. This will help you increase the inside/outside temp spread of the beans and develop the inside of the bean better later in the roast.
As well, you have a flattening and crash right before and into FC, from completely dumping the heat once FC was hit. I recommend making a P adjustment around 30 seconds before the assumed time of FC, and leaving that until at least 6-10% development time has passed.
Also!! Don’t trust preheat temps! I’ve found the auto preheat to be wildly inconsistent with the actual thermal energy in the drum, and bypass that by setting a preheat much higher than I actually desire, so that as the roaster is preheating at full power, I press the PRS button and charge as it hits my desired temperature. This has greatly helped my back to back roast consistency.
Hope those ideas help!
The pre-heat temp being super specific to the roast results really comes down to the batch size. That being said you do need enough heat at the start but lots of fan adjustments throughout the roast will be the first killer to heat and momentum.
I agree with @evanbouche. If you keep some of those things stable through most of the roast up until a bit before first crack you’ll have enough momentum to go into first crack and have some good development.
I typically do larger batches as I’ve started a business out of it. I’m typically doing 700-800g batches. But the principal is the same. Good preheat and stable settings in the beginning of the roast sets up the Maillard reactions which sets up the 1C and development time.
One thing that Munchow has encouraged and I’ve found to be super useful. Is whenever I’m dialing in a new coffee, run basically full power through a roast and notice where the different events happen. This gives you a baseline for you to work with and then start working backwards based on the type of profile and roast degree you’re trying to take the beans to.
Hope that helps!! Keep with it!