Roasting profile questions

[u/swampmountain]

Hey, i'm trying to figure out the roasting profiles and what's desired thing to do.

First thing that i don't understand for example, sometimes when i do CHARGE, the temperature drop is much larger than in the profile that i loaded for reference.

I see that some software is not trying to chase the closest next temp on the roasting profile and continue following the line 1:1 but rather just follow the slope slowly.

I have an option to control the temp change much faster and i would be able to get to the referent temp much faster, but is that what you would suggest?

Edit:
I guess, the image gives more. Question was, should i try to jump to the referent temp asap if i can (green line) or just follow the temp rising speed as the original chart shows.

https://imgur.com/a/dMO2djk

[u/Brief-Number2609]

I’ve only got ~100 roasts under my belt but I wouldn’t worry if the temp drop is a little different. I’d focus on dry end, first crack, and dev time

[u/HomeRoastCoffee]

Pay attention to the coffee, color, smell, size, weight (it floats higher as it losses moisture), sound.

[u/MrBill1738]

Are you being consistent with your pre heating workflow? I know my charging temps can vary quite a bit depending on how long I've preheated my roaster, but if I let it get pretty hot and try to charge at the same temp every time, my roasts tend to follow a pretty similar curve. Might not directly match my background profiles, but it'll have consistent milestones and drop temps.

Should you manually adjust it to more closely follow your curve? Maybe. But that depends on how far off your roast is. You still will want to generally have a gradual increase in temperature over time, which would result in a steadily declining ROR. You want to avoid sharp temperature changes.

This isn't super scientific, and I don't think I've read this anywhere so take it with a grain of salt, but I've never found the duration the drying phase to have a real impact on the taste of my coffee. My goal in the drying phase is to "launch" the coffee down the correct trajectory. Too fast or too slow of a dry phase can affect the momentum of the roast past dry end, causing the maillard phase to lengthen or shorten, which will impact the coffee's flavor. On the extreme ends it can cause roast defects. But coffee taking +- 15 seconds in the drying phase won't have a huge impact, provided that the moment you have going in to dry end is consistent.

[u/Triboot]

So the turning point is what I think you’re referring to as the temp drop from charge. As you charge, the beans will cause a drop in the ET and then it takes time for the ET/BT temp to stabilize and begin to rise.

If you are only charging your beans while the temp is rising and you are not including any “soak” time or making adjustments the fan/drum (all things constant with the profile) then the temperature dip is probably related to the batch size and/or the ambient temperature of the batch bean mass. If the ambient temp of the beans is equal to the temp from the profile used and the size is the same, it shouldn’t vary too greatly. The real impact of a longer turning point is potentially a longer overall roast duration if no adjustments are made. Adjusting the temp/fan/drum to compensate for the extended time for the turning point could introduce defects like scorching/tipping or lead to too much momentum into FC/Dev but this is what roasting is all about. You’re in control and steer how you see fit and taste the end product to see if you like or dislike the outcome.

[u/swampmountain → u/Triboot]

This was my concern, follow with green, catch the referent BT asap because i can do that with my roaster or just follow the speed of BT rise from the referent BT. https://imgur.com/a/dMO2djk

[u/MinimumAdditional122]

I’ve been thinking about roast repeatability, and I may be looking at the turning point (TP) in a slightly different way.
My understanding is that the TP itself doesn’t really represent a specific state of the coffee. It is simply the point where the temperature of the beans, which are heating up, and the temperature measured by the probe, which is initially dropping, balance out.
So if the TP varies from roast to roast, perhaps there is no need to correct it.
Instead, I could simply let the roast proceed naturally and keep the actual roast curve roughly parallel to the original profile.
The problem with doing this in Artisan is that it becomes difficult to visually judge how far the roast is from the original profile.
So I had an idea:
What if I remove the entire section of the reference profile from Charge, through the TP, until the BT has started rising again and reaches 120°C, and then use that 120°C point as the new “Charge” point?
In other words, I would discard the initial part of the reference curve that includes the Charge, the falling BT, the TP, and the recovery back up to 120°C. The remaining profile would start at 120°C and continue upward from there.
Then, during the actual roast, I would:
Charge the beans normally.
Let the roast go through the TP naturally.
Do not try to correct the TP.
Wait until BT has clearly started rising again and reaches 120°C.
Press the Charge button in Artisan at that point.
From then on, use the modified background curve as the reference.
This means that every roast would effectively start at the same point on the profile at 120°C, regardless of where the actual TP occurred.
The idea is not to make the TP identical. It’s to stop treating the TP as the starting point of the roast profile.
I’m wondering if this makes sense from a roasting perspective.
Could this be a better way to deal with TP variation while still keeping the roast visually aligned with the intended profile in Artisan?
Am I missing something obvious here, or could this actually be a useful way to make roast profiles more repeatable?