Hi everybody
i am a newbie roaster and trying to roast a low density beans for a commercial use. its a full city roast on color.
when i try the roasted beans at 2nd day of resting it is to much acidity. i need a chocolate flavor for my preference.
should i charge at lower temp ? or should i make any change.
any suggestions are welcomed

My knee jerk thought is you aren't roasting as dark as you think. You dropped only 11C past first crack.
Take this with a grain of salt, I've only been roasting about year.

the RoR curve is awfully flat, time to dry end is fairly long as the overall roast duration is at 18 minutes, and indeed the drop temp is pretty low as mentioned before (204'C)

I'm sure there a few folks here that would be able to relate to a 3Kg roast better than me doing 400g batches, make and model of your roaster will help them.
My thinking is that you'd want to use a moderate charge temperature but need more power early in the roast, gradually tapering off power as you go along.

At around 207 'C (or higher) drop temp you should have better results.

I would also change Axes settings temps to a narrower range

On that graph, if that maroon (dark red) colored line is fan speed, it was too low after the soak / turning point. That may be the reason for flat RoR line in the mid span. You want to increase that after the soak.

You might want to try charging at a higher temperature, as your drying time is really long compared to your overall roast time. Try 225 to 250 C and see what happens. This should give you a much shorter drying time and a much higher ROR during that phase. Doing this will give you the ability to increase your fan and cut your BT as the roast progresses; your BT curve (and ROR) looks too flat during most of the roast to me. By heating the beans more rapidly, the beans will have more time to soak up the heat and the beans should be more evenly roasted from outside to inside. As for the drop, usually 1C lasts about 17 degrees C. So, as others have mentioned, you're not roasting anywhere near as dark as you think you are. Maybe do a batch and listen to the onset of 2C. See how that tastes. If it's too smoky, then try to drop a few degrees of BT after 1C has ended. Platy with the drop temp between end of 1C and start of 2C to find your chocolate.

semoga beruntung
Maurice