My 5kg USRC Roaster, I took the the plunge - Page 7

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
Milligan (original poster)
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#61: Post by Milligan (original poster) »

mkane wrote:Papery taste with seasoning beans. I'll be darned.
I haven't gotten my seasoning greens yet. I scratched together roughly 5lbs of Costa Rican Tres Rios and 3lbs of El Salvador. Both washed. These beans should have been relatively fresh. I called them throw away because I didn't particularly care for them but bought too much. I got antsy and wanted to put something through it

Milligan (original poster)
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#62: Post by Milligan (original poster) »

EddyQ wrote:This papery taste may go away after a few more days.

Overall, your profile looks pretty good. But I don't think your dry is too quick. It looks a little over 4min, which is actually a tiny bit long. Your turning point temp is a bit high. I cannot tell if it is due to gas too high or too high of charge temp. With my 1K roaster I keep gas almost off until 1.5 min and then give it all the burner have. My turning point is about the same time as yours and range between 150 and 180F. It too high, my next roast would be charged a bit lower temp.

The roaster looks amazing BTW!
Thanks for your perspective. It is great getting a variety of feedback. The beans still have the "bready yeast" aroma of beans right out of a roaster after being cooled. Not sure if I'm describing that aroma correctly but it's pretty common smell that goes away after a day or so. I'm used to cupping the next morning when doing 100g batches but having 8lbs in a sealed tub may be a different dynamic. I'll cup again after it sits for a bit. My wife really liked it this morning but I ground some for her before I went to bed so they likely off gassed significantly before she brewed in the morning.

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mkane
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#63: Post by mkane »

Simple amazing 8lbs of coffee can dry in 4minutes

Milligan (original poster)
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#64: Post by Milligan (original poster) »

I got to a volume selling coffee that I needed to start using the USRC. I've done a few roasts here and there but haven't had enough volume for it to make sense warming it up. My time with the Cormorant has demystified the process, so its a lot more fun dialing in the USRC now (instead of fumbling about.)

I did my first roast day with it.



Was going for a solid medium roast on this first attempt and got a relatively good RoR, but it dropped too fast for my liking. That caused a long Maillard and development phase to get to my target end temperature. I entered FC at a low RoR. The coffee tasted quite nice though. No hint of roast at all. The best I've had of this particular coffee actually.



I tried to get through development a little faster on this next one and targeted a bit higher finish temperature. I'm not sure if I'm missing the start of first crack, it seems to be much quieter than I was thinking it would be. This roast ended up darker than I was expecting so I'm thinking FC may have started closer to 375, which would make sense. It did go faster, but I do not care for the high RoR during drying that drops down significantly entering Maillard. I'm considering doing a soak to get my peak RoR around 35 instead of 40 and charging higher at 400F to get through drying at an appropriate time. That may make my RoR more stable.



The last one has a lot of Ethiopian coffee and they took the heat. Not liking how the RoR swings down on the way to dry end. This one could have definitely used a soak. I want to bring my RoR up to around 15-17 as I enter FC.

I'm looking into my gas supply. I think the 1/2" pipe may be too small to get the full power out of this roaster. I can see the line pressure drop as I go to maximum flow, which probably shouldn't be the case. Hoping to smooth out these graphs and spend less time in Maillard and development.

One thing I do like is that it is a much smoother machine to operate than the Cormorant. The thermal mass smooths out the gas changes where the Cormorant acts a little too quickly. I like the freight train feel of the bigger roasters. Set it to a general direction and it chugs right along. It was surprisingly easy to get pleasant behavior during development. Still much to work on though! Looking forward to tasting all these after some rest and make adjustments.

SutterMill
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#65: Post by SutterMill »

Milligan wrote: I'm looking into my gas supply. I think the 1/2" pipe may be too small to get the full power out of this roaster. I can see the line pressure drop as I go to maximum flow, which probably shouldn't be the case. Hoping to smooth out these graphs and spend less time in Maillard and development.

One thing I do like is that it is a much smoother machine to operate than the Cormorant. The thermal mass smooths out the gas changes where the Cormorant acts a little too quickly.
Curious what USRC specs as a supply line diameter. I'd be surprised if it wasnt 3/4" min. Your last comment reminds me why I'm looking for a well built 1kg drum roaster. The SR800 is good, but the temp changes are faster than I can correct for. Thanks for the update!

Milligan (original poster)
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#66: Post by Milligan (original poster) replying to SutterMill »

Yes, I was mostly doing back of the napkin calculations when I sized the pipe. It tee's directly off the main line right at the meter. 100k BTU furnaces use 1/2in black pipe so I figured doing 8lb loads @ 5000BTU per pound would have been plenty, but perhaps not. Luckily, it isn't in its permanent spot so I will likely run a 1" pipe next time to have head room if I ever size up in roaster. I think I'll check my regulator to make sure it is outputting the full amount.

I'll check the documentation, but I believe you are right about the 3/4".

I've enjoyed the Cormorant and have learned to weave around some of its quirks but I'd enjoy some time behind a heftier small roaster like the MC 500g, BC 1 or 2, Arc 900, or similar. The 30lb Cormorant vs a 125lb+ 1-2lb roaster would be a fun experience. Warm up on the 5kg roaster is a long process though, so it isn't worth firing it up for only one roast. It takes around 45mins to do the whole warm up routine. Hopefully I can bring that down as I get to know it more.

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#67: Post by Capuchin Monk »

Milligan wrote:It takes around 45mins to do the whole warm up routine. Hopefully I can bring that down as I get to know it more.
Any thoughts on recirculating the exhaust air after filtering? It would make the heat supply more efficient. BIG roasters do and I wonder if this one qualifies to be in that category...

Milligan (original poster)
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#68: Post by Milligan (original poster) replying to Capuchin Monk »

It is an interesting idea. I'm not sure how I would approach doing that with this roaster. It is very traditional so it draws air from under the burners, runs through the drum, through a top pipe, through the fan, and out the exhaust system from there. So I'd need to somehow dump it back under the roaster to recirculate. I can definitely see why some bigger systems do that.

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#69: Post by Capuchin Monk »

This video and the following link show the diagrams on how the heated air gets recirculated.
https://library.sweetmarias.com/roastin ... air-fryer/

Another option (if diy is available) is the furnace heat exchanger which can route the exhaust and intake air through for heat exchange.

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baldheadracing
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#70: Post by baldheadracing »

That is with a blower burner. The USRC and similar roasters use an atmospheric burner. You can adjust the air:fuel ratio in a blower burner to accommodate recirculated air. That is not feasible with a conventional atmospheric burner.

For a good description of the differences between burners on "shop" roasters, skip to 6:10, segment ends at about 11:50.
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