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New to roasting, need help with SR540, seeking Berry Bombs!!!
JediMasterAubie
A former coworker convinced me to take the plunge and buy a FreshRoast SR540.

I have since modified it with a HomeRoasters extension tube (Not the Razzo) as well as Razzo's chaff collector extension. These two changes have made all the difference in getting consistency across a batch, but I have been struggling for months to even get halfway to a good roasting profile.

This coworker introduced me to the wonder of the berrybombs and I've been roasting almost exclusively Ethiopian; whatever Burman has from that country at a given time, and what all my research says should bare the best results.

I'm getting nowhere on my own. When I asks the facebook FreshRoast group, I get answers all over the map and none of them get me even close.

I came to this forum and thought I'd try to boil this down to 3 critieria, and try to hone in on things as we go.

1. Amount of green beans. I typically start with 150g. With the extension tube, I get great circulation at most fan settings. Should I change that to change the air flow restriction?

2. Drying time. Is there a consistently good drying time for this configuration for a given amount of beans? Am I just looking for a particular color or something before increasing heat and dropping the fan?

3. Ramping heat settings. I see a lot of low and slow and a lot of high and fast. I'm assuming the amount of time to first crack matters but I haven't found consistency in opinions or results in getting berry flavors. BTW, I'm taking things to first crack + 30 second.

If anyone can provide any meaningful guidance, I'd be most grateful. I'd have given up by now if I hadn't been shown this is possible; I just need some help getting there.

THANKS!!!!
Mike
 
allenb
I sense a shift in the force is needed Jedi.

So, to start with, as you've probably already noticed in the world of coffee roasting, there are no hard fast rules for a magic profile for either fluidbed or drum roasting. What I used to believe was the only way to achieve great coffee I've now thrown out the window and I've been playing with drum and fluidbed roasting for at least 25 years.

Lately I've been using a very simple, basic short roast regimen for small fluidbeds based on suggestions by Jim Schulman over at HomeBarista that renatoa was nice enough to post in a thread a while back. The method requires being able to read and control the temperature of your hot air entering the roast chamber instead of controlling based on bean temp.

The hot air temp profile I'm getting excellent results from is going straight to around 320 to 350 F air temp for 4 minutes and then going to 510 F for the remainder of the roast. This results in the beans hitting the beginning of first crack anywhere from 7 to 8 minutes and finishing the roast at around 60 seconds afterward for a somewhat light roast. I've tried using graduated ramps between stages to make it more elegant but the cup never seems to improve and actually suffers. It goes against everything I use to believe about how to achieve the best roast but this works for me at the moment with most high grown coffees.

Post often on your continued experimentation.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
renatoa
The final part of the JS recipe is also equally important as the numbers, imo, and should be quoted every time when discussing this approach:

"...the heat inputs required moment by moment to achieve this ET curve is based on the roaster's thermal characteristics, and is different for every roaster design."

What I see specific to FB machine is the airflow management, and don't forget that every airflow change has impact on heat.
We have examples of roasters who managed to drive a complete roast changing the airflow only, using a constant power level !
This is not a general case though, can be done with sweet spot loads only, and that fixed power level needs some trial and error to figure it.

As a rule, most FB machine airflow is high at the start, because beans are heavy, and needs maximum lift force.
High don't mean the highest fan position available on the knob, but the highest position that barely move the beans.
While beans are drying, they lighten, and airflow needs to be decreased, in order to keep a moderate fountain height, else the beans will be ejected in the chaff collector. This airflow/fan decrease will led to a temperature increase.
For a better machine behavior understanding I would try to build a curve of fan/temperature for a fixed heat medium setting.
You need this data for the ramp part of the recipe, from charge/drying temperature to the roast temperature.
Probably will be a sequence of lower fan-wait-increase heat- wait actions, but the exact timing needs some data about the machine natural curve, else would be a guess, trial, cupping and error Grin
Edited by renatoa on 08/27/2021 2:34 PM
 
allenb
Jedi posted:

Amount of green beans. I typically start with 150g. With the extension tube, I get great circulation at most fan settings. Should I change that to change the air flow restriction?
I would find the highest weight that still allows good circulation throughout the roast and stick with it

2. Drying time. Is there a consistently good drying time for this configuration for a given amount of beans? Am I just looking for a particular color or something before increasing heat and dropping the fan?
I have found for most coffees with fluidbed roasting that I get very good results with a 4 to 4 1/2 minute dry time. Dry being at the point where the coffee is just starting the transition from pale green into a slight yellow.

3. Ramping heat settings. I see a lot of low and slow and a lot of high and fast. I'm assuming the amount of time to first crack matters but I haven't found consistency in opinions or results in getting berry flavors. BTW, I'm taking things to first crack + 30 second. For a fast roast, I get best results by never going faster than 3 minutes from end of drying to first crack. For extracting the most berry flavors from Ethiopians and various naturals, definitely keep it on the lighter side but not so light that you don't hit minimum development needs. For a given coffee, this takes experimentation and cupping to find the sweet spot

On the subject of low and slow versus high and fast, my opinion from experience is that drum roasters, for what ever reason, seem to do better extending the roast to at least 10 minutes. Fluidbed, from my experience, like a shorter roast. This will vary with some coffees. For instance, in a roasting competition with all participants using the same drum roaster a few years back, all of the winning coffees had a finish time of around 8 to 8 1/2 minutes which to me, is too short for a drum roast.

I know it's frustrating when someone consistently gets less than good results in the cup. Only way to get out of the rut is to try different strategies but remember to never make more than one adjustment at a time when experimenting or you'll never know what was the true cause of an improvement.
Edited by allenb on 08/28/2021 1:24 PM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JediMasterAubie
Thanks allenb

I increased the amount to 215 which I think is nearing the limit of when the beans start to clog in the wider part of the expansion tube after the beans themselves swell up. Was able to keep reducing the fan (with minimum heat) and have just enough movement to keep all the beans circulating decently well for 4 minutes, but I think was well into the yellow color well before then (maybe 2.5-3.5 minutes). Think I'm turning down the fan too quickly?

After drying I cranked up the heat a bit and really didn't touch it after that. I hit first crack just shy of 3 minutes after drying, ran for another 30 seconds, and then started the cooling cycle at max fan.

At least the next morning, hasn't really improved. I've read it really takes 2-3 days post roasting for the flavors to get there so maybe tommorow morning?


If you see anything i'm doing that's glaring at you, please let me know. Definitely curious what your thoughts are on better modifying the drying cycle.
 
allenb
Are you able to reduce heat to allow getting closer to 4 min when you start transitioning from pale green to yellow/brown? If yes, do so whether it takes manipulation of the air output or a combination of things. 3 minutes from yellow to first crack is not too quick for many coffees but I wouldn't allow it to go even a few seconds less than that.

Try and find a heat output during the browning phase that allows you to go at least 3 minutes from dry to first crack and let it go for another 60 seconds after the beginning of first crack before killing the heat. If you are in the right range for heat output, you should be able to go the 60 seconds without going past a light roast.

Hopefully you can achieve enough control to try this out with your machine.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JediMasterAubie
Are you able to reduce heat to allow getting closer to 4 min when you start transitioning from pale green to yellow/brown? If yes, do so whether it takes manipulation of the air output or a combination of things. 3 minutes from yellow to first crack is not too quick for many coffees but I wouldn't allow it to go even a few seconds less than that.
I'm starting at the lowest heat setting for the drying phase. I can increase fan to have less heat build up at the bottom of the chamber.

Try and find a heat output during the browning phase that allows you to go at least 3 minutes from dry to first crack and let it go for another 60 seconds after the beginning of first crack before killing the heat. If you are in the right range for heat output, you should be able to go the 60 seconds without going past a light roast.
Can certainly increase the time past first crack
Edited by JediMasterAubie on 09/01/2021 7:51 PM
 
JediMasterAubie
Well Allenb,
It took 2 tries but I did a better job hitting the times you specified, 4 min to dry,first crack at 7:37 total time, and then 1 more minute; but minimal changes in the outcome. I'm just getting really, really weak, neutral flavors.

I'm keen to assume there's very little wizardry to be had between the drying and first crack, which makes me wonder about the two phases outside of those bounds.
It's possible my novice definition of pale green/slight yellow is much darker than your and I'm pushing the heat too soon too fast; does that sound like a probable culprit?
On the other end of things, the 1 minute past first crack . . . I have not been adjusting my settings at all after first crack; should I be modulating my heat or fan speeds at all during this phase?

Thanks for baring with me!
 
allenb
If you can pull it off. Find a way to measure the air at the top of the roast chamber preferably using a thermocouple sensor based thermometer. For hot air roasters, this is close enough to a representation of bean temp to allow determining what your bean temperature curves are. I think you will not be able to determine what may be going wrong with your roasts without this. if you are able to do this, shoot us the numbers every 30 seconds and we can help you figure this out.

Have you tried different coffees from different sources to make sure you are using optimal beans. A lot of folks totally rearranged their roasters at a huge expense of labor and money only to find their large stash of greens were sub par.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JediMasterAubie
I can look into the thermocouples. I had considered it but had enough people that's really over-engineering it. I assume by at the top of the chamber you mean the tip of the probe sticking just below the bottom of the chaff collector?

I've been using Burman exclusively; they seemed to have a great reputation and their warehouse is around the corner from where I work. I've tried a few different beans from them. This last month or two I've been working with Ethiopian Goji natural (had read among the most fruit-fwd beans out there); order I placed earlier today is for some Yirg (was the only ethiopian natural I could get from them right now).
 
allenb
Yes, just below the chaff collector, not low enough to be contacted by beans. Try to arrange it where it will stay put but allow easy removal and emptying of your chaff collector.
For the purpose of finding a basic roast strategy with your machine, get yourself a couple of lbs of a known highly rated colombian or kenya, wet processed, not natural, and get that to cup well. Then, when roasting the berry bombs, you can make tweaks to the process to get the most out of those.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JediMasterAubie
Going to try to get to the temperature data collection in the next day or so. But I am curious, why the temperature near the top of the chamber? Why not down in the beans?
 
allenb

Quote

JediMasterAubie wrote:

Going to try to get to the temperature data collection in the next day or so. But I am curious, why the temperature near the top of the chamber? Why not down in the beans?


Fluidbeds are problematic in getting an accurate bean temp due to being almost impossible to avoid the probe being influenced greatly by the hot air stream surrounding the beans. I have found that sensing the upper portion of a fluidbed RC gets relatively close to bean temp assuming one isn't flowing an excessive amount of air at any stage of the roast.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JediMasterAubie
I ran it again and collected the temperature data as you described. It did run a bit longer than my last batch, had to make some late power adjustments to get First Crack to happen at 8:39. Not sure what was different from this weekend. Please let me know if anything stands out.
JediMasterAubie attached the following image:
capture_26.png
 
renatoa
Drying too long, as I see from the scroll above 300 F/200 C after minute 6.
And the total length is a bit too long for a FB machine, where FC happens under 8 minutes usually.
I would push more on heat at start, to reach 300F by minute 4, then less heat increase. The accumulated momentum due of faster drying will lower also the total roast length, thus FC will happen faster.
Try to find the heat level where do you have stable 300F in the roast chamber, with machine empty, start a preheat at this setting, charge beans while keeping this level of power, then increase as necessary to have dry ending under minute 5.

PS: re-reading the thread I seen my post duplicate some allenb directions.
Wasn't my intention, simply this is how I would approach the roast on such machine.
 
allenb

Quote

PS: re-reading the thread I seen my post duplicate some allenb directions.
Wasn't my intention, simply this is how I would approach the roast on such machine.


No worries, i agree with your assessment and recommendations and shortening times should yield better cup results from my experience
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JediMasterAubie
Thanks to both of you for the feedback. I knew something went sideways last night when it ran long (not sure what I did differently), but figured I'd get some meaningful feedback (And I did!) instead of just scrapping it.

Following Renatoa's suggestion of finding the settings for an empty chamber steady state at about 300F. Then preheating the chamber to 300F, and dropping in the beans.

I was able to get the temp back up to 300F at about 3:00, and First Crack at 7:35, Hitting the Cool cycle with no adjustments to the fan speed at 8:35. I've attached another picture showing my new times and temps, also captured my fan and heat settings (If nothing else to more directly indicate when I'm making changes).

Thanks!
JediMasterAubie attached the following image:
capture_27.png
 
JediMasterAubie
Any recommendations on how to steer the roast since the last try & data set?
 
renatoa
How was the taste of the roast from the table above?
 
JediMasterAubie
Not a whole lot of flavor in any regard. I tried it this morning with both my drip coffee maker as well as my french press to make sure it's not just my drip machine causing my problems.


Do I want to speed up/slow down how long it takes to get to that final temperature or some other different tack?

Thanks!
Edited by JediMasterAubie on 09/20/2021 10:12 PM
 
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