Fresh Roast SR800 - 1/2 lb Air Roaster - Page 19

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
Iowa_Boy

#181: Post by Iowa_Boy »

Hi all, I am finally improving my roasts with the SR800 and V4 Razzo 12" tube. I have really struggled with tipping/scorching, especially for natural beans. So I have been focusing on optimizing my technique with washed beans first. I have lengthened my drying time, which has helped. Seemingly more important, I was entering first crack with too much heat, and I think a lot of the scorching was having after 1C started. I am now getting much better results. The result is much more even roasts, better sweetness, and development.

I originally thought I could just use the internal temperature and bean color to optimize, but I realize that to improve further I really need to have a BT probe. So I am ready to venture into the Artisan world!

My question is: It seems like a 30 cm thermocouple would be best to get the probe into the bean pile. I have found some inexpensive 30 cm K type 2 mm thermocouples on eBay, that ship from overseas. I am sure they aren't the best quality, but wondering if anyone has recommendations before I order? Need to order a phidgets setup as well, but that should be easy.

mtbizzle

#182: Post by mtbizzle »

Iowa_Boy wrote: My question is: It seems like a 30 cm thermocouple would be best to get the probe into the bean pile. I have found some inexpensive 30 cm K type 2 mm thermocouples on eBay, that ship from overseas. I am sure they aren't the best quality, but wondering if anyone has recommendations before I order? Need to order a phidgets setup as well, but that should be easy.
Phidgets sells good thermocouples. You can buy their usb thermometer as well, or you can get something like the mastech ms6514. Either will hook into your PC to feed data to Artisan.
I am now getting much better results. The result is much more even roasts, better sweetness, and development.
Tell us about your approach!
hercdeisel wrote:My general approach is to...
It sounds like your temp numbers are from the base (or are they from a thermocouple?). Is the preheat a temp from the base? I'm a bit surprised by your first crack temps. I almost always get FC start temps around, 390-410, never around 475 --- but I'm using a thermocouple going into the beans. Are you using the stock roasting chamber, or one of the taller aftermarket ones? I'm always curious to try other people's approaches they have found success with

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jfjj

#183: Post by jfjj »

I have the FR extension tube and a mastech 6524 for my temp probes. I almost always get FC around 390-415 from the probe and 485-505 from the base temp. The probe will help mainly to tell you your ROR. You'll want to enter in around 20-10f ROR ans depending on your roast level gauge how long you want to be there. Lately I've been doing light roast no more than 1:15 past FC and 10-15f increase from the FC start.
- Jean

mtbizzle

#184: Post by mtbizzle »

jfjj wrote:I almost always get FC around 390-415 from the probe and 485-505 from the base temp. The probe will help mainly to tell you your ROR. You'll want to enter in around 20-10f ROR ans depending on your roast level gauge how long you want to be there. Lately I've been doing light roast no more than 1:15 past FC and 10-15f increase from the FC start.
Thanks, yeah that is consistent with my data. I have a 9.5" tube and mastech as well, same 390-410 FC start values. I'm about to start roasting again (outside temp permitting), I'll try out your parameters as ballpark targets, light roast with roughly 10 ROR at FC start, drop 10-15f past FC start temp. Do you have any advice for managing ROR around FC start, especially for light roasts? I often found that my ROR will either sink too low / bean loft will be too high unless I adjust settings late in roast. But late adjustments seem to really throw off ROR, temp.

jfjj

#185: Post by jfjj »

Still trying to figure that one out. I will say that airflow has significant impact on temp, while temp adjust does impact it it's easier to play with the temp than airflow. I normally have airflow around 4-5 into FC and depending ambient temperature around 3-5 for heat. I also noticed on some beans they vary in ROR so you have to just watch that you aren't skyrocketing to 60 but if it shoots to 15-25 just watch the BT to make sure the temp isn't going up fast rather than ROR.
- Jean

MNate
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#186: Post by MNate »

Iowa_Boy wrote:
My question is: It seems like a 30 cm thermocouple would be best to get the probe into the bean pile. I have found some inexpensive 30 cm K type 2 mm thermocouples on eBay, that ship from overseas. I am sure they aren't the best quality, but wondering if anyone has recommendations before I order? Need to order a phidgets setup as well, but that should be easy.
Did you ever buy one?

I bought the 20cm and 11cm from Phidget and stuck the 20 down the top but it was still too high. Finally I taped the 10 to the 20... fancy, I know, and combined they are a good length. And yeah, the reading does seem better in the bean mass than above, though either gives you some data to drive your decisions.

Truthfully I haven't roasted in a month so I have some things to try from what you've said.

But a few days ago I got out some beans I had roasted a month ago, both with visible scorching. I wasn't expecting anything drinkable but they actually were really very good! So together with your report I have some hope that things can become consistently good.

Iowa_Boy

#187: Post by Iowa_Boy » replying to MNate »

In the end I have decided not to get a 30 cm probe. I spent way too much time researching them, and for whatever reason, a 30 cm 3mm ungrounded probe is kind of pricey. The companies I found that had them were Evosensors (about $48 shipped), Omega (about $46 shipped) and Thermoworks (about $56 shipped). After seeing what others were using on the FB forum, I decided to get the Perfect prime TL1004 ($12 shipped) as a starting point since reviews were good. Similar to what you are doing, it seems like people are just extending the wire into the extension tube to reach the beans. I liked that the PP TL1004 wire can be bent so the probe is at 90 degrees, so it can be placed horizontally or vertically. Will report back on how it works! Hopefully the phidgets will arrive this week and I can get started.

It seems like every FR setup behaves a bit differently, but here is what is working for me to help avoid tipping/scortching:
1) I have prolonged the drying phase, currently it's about 4.5 minutes. I stopped preheating, and start on F9H3. After about 3:00 minutes, I start decreasing fan and raising the heat. I still need to do more testing on the preheating vs not preheating, as my drying phase seems a bit too long.
2) From yellowing to FC, I was previously mostly dropping fan speed. Sometimes I would get down to 2 or 3 fan speed. On the V4 razzo, there is a clear up and down flow of beans. That down flow is too slow at low fan speeds, and I believe the contact time with the glass or base can scorch. So now my approach is to decrease fan some, but also slowly increase heat so I can move roast forward but not get too low on the fan speed. I have learned with my setup going below F4 isn't good. Currently, I am hitting first crack around 8:30-8:45.
3) FC onward. I think this is where I was making biggest mistake. I had too much heat going into first crack (probably from dropping fan speed too much), and base temp would continue to rise considerably after first crack started. For my setup, I hit FC when the base temperature is around 462 (I am sure it would be much lower with a BT probe). I now regulate fan and heat to keep base temp close to FC temp of 462. That has really helped eliminate ashy/roasty flavor. Will be interesting once Artisan is running to actually see what my ROR is. I am hitting around 19% development time for last few roasts.
4) End of roast - I now hit cool down, let it run for a few seconds, and then remove the tube, quickly remove chaff collector, and dump into a separate cooler. I let the cooling cycle complete. I can't see any advantage to letting the beans cool in the extension tube, as I think the beans continue to roast slightly and are at risk of scorching. So external cooling seems better.

My recent roast looks like this:
Time Fan Heat Base Temp
0 9 3
1 9 3 316
2 9 3 326
3 8 3 339
4 7 6 360 Yellowing at 4:30
5 6 6 389
6 5 7 406
7 5 8 424
8 4 8 451 FC at 8:45
9 4 8 462
10 4 8 465
11 4 8 468 Drop at 10:45

This was for a Daterra Sweet Blue.
Looking forward to seeing how the ROR curve actually looks once I have it setup!