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New to roasting and could use helpful advice w/SR800 roasting.
Skyhawk4
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Posted on 01/28/2024 9:23 AM
I have a Fresh Roast SR800 with extension tube and using Artisan to roast dry process Ethiopian and sometimes I roast dry process Yemen beans. My goal is to roast to Full City. I have been working on improving my roasts over the past 6 or so weeks and have about 30 roasts so far. It has been challenging for me as I've tried to learn how to use my roaster to produce good roasts. Here is where I am at now. My Artisan temps from a probe that is positioned about a half inch into the bean mass, give me temperatures that appear to be about 23-degrees hotter than what the beans actually are at (that really threw me at first) so I just note it and compare roasts with the understanding that Artisan is that much hotter than the beans really are. Anyway, I will attach an image of the Artisan chart, and also an image of my roast temps during the roast with my air/heat setting adjustments.

1. My moisture losses are between 13.5% and 14.5% for most roasts of dry process beans. I like this.
2. My three phases are around 40% Drying, 28% Maillard and 32% Development.
3. Total roast times are running around 9.5-minutes to drop.
4. Specifically, I am struggling to get the Maillard phase right. It seems like I get to the Maillard in around 3.5-minutes and First Crack and Development around 6.5-minutes. Is that enough time in Maillard? If not, then should I just go easier on the air/heat once I hit Maillard? But if I do that then it takes me into a longer overall roast time that is closer to 11-minutes... is that okay or is it too long for an air roast?

Thank you very much for any advice you can give me.
Skyhawk4 attached the following images:
yemen_bani_haraz_dryprocess2.png yemen_bani_haraz_dryprocess.png
 
Ben N
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Posted on 01/28/2024 9:45 AM
I'm not sure how to help, I do have a question though. Your beans are still at room temp at 1:30, almost to minute 2. That makes me think your drying phase might be pretty short, but I am not really sure how that is judged. Hopefully someone can clarify.

What are you trying to improve? Is there a flaw in your roast, or a flavor profile you are hunting?
 
renatoa
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Posted on 01/28/2024 10:23 AM
Please, can you elaborate a bit about the 23 dgr hotter part ?
400F, i.e. 200C looks like a normal FC temperature... what values are you expecting then ? puzzled...

Also, 77F (25C at charge looks like a normal ambient temperature, so you don't preheat at all ?
If true, I don't understand that temperature drop pushing TP into negative temperatures range, of Celsius scale...
 
Skyhawk4
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Posted on 01/28/2024 12:44 PM

Quote

renatoa wrote:

Please, can you elaborate a bit about the 23 dgr hotter part ?
400F, i.e. 200C looks like a normal FC temperature... what values are you expecting then ? puzzled...

Also, 77F (25C at charge looks like a normal ambient temperature, so you don't preheat at all ?
If true, I don't understand that temperature drop pushing TP into negative temperatures range, of Celsius scale...


My thermometer doesn't seem to register accurate temps. I can see visually that the Development ends at around 3 minutes. My roast was ended at that 9:20 mark at an indicated Artisan temp of 464 degrees F. By weight of the beans (before roast vs afterwards) the 225g roast ended at 191.5g for a 14.9% moisture loss. I have a roast level card from Sweet Maria's that shows that amount of moisture loss as being a tiny bit short of Full City+ (they have FC+ as 15.1% moisture loss). The same card lists Full City+ as being at 442F. So I just thought my Artisan temps (that read 464F) must be off by about 22F or so. But regardless of what the actual temperatures are, I thought that if I wrote down my temps from roast to roast, minute by minute, I could still adjust my roast plans based on that... the temps are just a "marker" that can be adjusted as needed up or down from roast to roast - even if they are not true temperatures... as long as I was consistent I thought I would be able to recreate roasts. And so far I have been able to recreate roasts.

I have not been preheating my roaster. To be honest I didn't even know that an air roaster like the SR8000 needed to be preheated. Like I said, I'm pretty clueless about it all at this point and don't know what's best.

That's why I finally posted here this morning. I'm confused a bit about it all. I do believe my FC is on point at 400F, but from what I've read online I thought the Maillard phase was supposed to be longer than what I am doing - and wondered if I should try to throttle the temps from Drying End to stretch out the Maillard phase longer? Or is my time okay? On a positive note, the coffee I am getting now tastes really good to me, and it was terrible in my first roasts... downright un-drinkable. Gradually, I adjusted my heat and time and got the roasts better bit-by-bit until now I like the flavor of my coffee... but I wondered if there is a way that I can get even better flavor if I lengthened that Maillard time? LOL, as I type this I realize I must sound like a total idiot.
 
renatoa
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Posted on 01/28/2024 1:28 PM
Some preheat is required because that glass can take a lot of heat...
You can say... so what, will take this factor into account, and dial the power a notch up, to compensate the glass energy.
This logic work only if you do a roast per session and nothing more... if more roasts, then the second, third, etc... will start with different glass energy than the first.
For commercial roasters this balancing is a separate chapter in the machine heat management, i.e. BBP = between batch protocol.
For multiple roasts case would be a good idea to preheat the machine at first roast at a level close to the temperature you drop the beans, if after drop you intend starting immediately the next roast, and don't let machine cool a bit.

Another good reason to start with a preheated machine is that way you minimize differences between summer and winter roasts, i.e. influence of ambient.

Regarding the temperature offset, sorry, too much assumptions in that reasoning... and some of them are heavily dependent on roast style/school.
For example SM temperatures charts are done for classic commercial roasts, and not apply for specialty 3rd wave roast styles.
442F , i.e. 227C as drop value is awful, most roasts known as omni, are droped before 212C.

Somewhat you are right, the temperature measured by a probe in a roaster is a convention, because what is actually measured is a mix of air and beans, but... if your FC temp is in the 200C/400F ballpark, then your measurement can be considered good.
What matters more from that point forward are the differences, not the real values. If I want to drop my beans 12C degrees after FC, is less important that FC happens at 190 or 200C...
 
Skyhawk4
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Posted on 01/28/2024 6:32 PM

Quote

renatoa wrote:
Some preheat is required because that glass can take a lot of heat...


That was fantastic advice. I just finished my first roast after a pre-heat. It made a difference. Thank you, because I had no idea you needed to do this for an air roaster like the SR800. Here is why it made such a big difference, the thermocouples apparently needed this warm up to accurately track temps in the beginning of the roast. I ended up with a beautiful roast. Drying was 38%, Maillard was 41%, Development was 21%. Now I can roast better with better temperature tracking.

I think the major lesson learned so far is that there is (for me anyway) a steeper learning curve necessary to fully understand my roaster. It seems like things happen very fast on the SR800 requiring very close monitoring of the roast and more adjustments than I thought would be required during the roast. But I think I have this roaster (finally) down well enough to get repeatable good roasts.
 
Ben N
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Posted on 01/29/2024 9:13 AM
The new schedule sounds good to me. I use an sr700 (ancient version of what you have), I will preheat to around 250f and hold it for 2-3 minutes before I charge beans. If I don't preheat I get some vegetal notes that I am not real fond of. A light roast takes me around 8 minutes, dark stuff can be 10+.

These mini fluid beds are much faster than a drum. Just bear the speed different behavior of different roasters in mind while you are looking at different peoples recipes and curves. Your ROR graphs will be a little different from other styles of roasters at the beginning as well.
 
Skyhawk4
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Posted on 01/29/2024 9:36 AM

Quote

Ben N wrote:

The new schedule sounds good to me. I use an sr700 (ancient version of what you have), I will preheat to around 250f and hold it for 2-3 minutes before I charge beans. If I don't preheat I get some vegetal notes that I am not real fond of. A light roast takes me around 8 minutes, dark stuff can be 10+.

These mini fluid beds are much faster than a drum. Just bear the speed different behavior of different roasters in mind while you are looking at different peoples recipes and curves. Your ROR graphs will be a little different from other styles of roasters at the beginning as well.


Thank you for that information. It's helpful regarding your length of roast time. And I just did not realize I needed to preheat for my air roaster. But it makes a difference in the entire roast process for my machine. I'm liking a medium roast at around 9 minutes. I am finally getting comfortable with my entire process now from green bean selection (what I like), to the roasting with this particular roaster setup, and through the actual brewing of the coffee - to what I like best. I was reflecting this morning that it took about a year to get the entire process down. LOL, even buying the right green beans was overwhelming for me at first. Now I know what I like. Anyway, thanks for the help.
 
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