I made a Chemex pot this morning from the roast above with my usual ratios. Bright and fruity, no defects to speak of, but little body as well. This is a tough coffee to get a rich body from anyway, but there is an obvious decrease in solubility. I will try some as espresso tonight to see if the lack of filter adds something.

So the next experiment is to try a similar roast, but deviate in two directions: One with the same development time, but hotter drop temp, the other with a similar drop temp but 15 seconds more development time.

This is what it looks like just sitting there.


This is what it looks like when it's ready to roast


Along with gutting it, I also made a 2,300 watt heating coil to replace the smaller factor one.

I hate to post this one because I screwed it up again by dropping the beans in before it gave the load bean horn, there fore, it did not start in the PID mode and took off. The roaster is so fast, it had gotten above my setpoint before I was able to get the PID turned on, and it had to play catch up. I'm running a super fast exposed bead, wire thermocouple in the bottom of the roast chamber so that's why the readings are a little bouncy. Now that I no longer run the chaff catcher in the top, I've ordered a metal probe to go in from the top and see how that does.


This is the Log but it didn't save the profile to it for some reason. If you notice on the heat, the thing is just coasting with a 120 gram load in it, and if I go down to 100, it's almost not controllable. 175 to 200 grams is where it runs best at. I also have to cut back on the air volume as the beans dry or it dries them out too much.

Here's the profile I ran, at 180F RoR of 34 to 300: at 300f RoR of 20 to 340: at 340 RoR of 19 to 397: at 397 RoR of 6 to finish. My time were off to where I wanted to be in the phases so I've got to tweak that some.

Roast Logger Copyright (c) Tom Coxon (GreenBean TMC).
Roast started at 09:47:37 14/01/2016
Elapsed time T1 T2 Event type
Heat Fan
0:00 208 224.3 Beans loaded
75 100
0:05 164.9 199.2 timer
100 100
0:10 154.6 235.3 timer
100 100
0:15 157.6 257.3 timer
100 100
0:20 165.6 274.9 timer
100 100
0:25 179.8 290.9 timer
100 100
0:30 192.3 295.5 timer
65 100
0:35 205.1 286.9 timer
45 100
0:40 213.4 273.3 timer
45 100
0:45 220.5 265.7 timer
45 100
0:50 225.5 254 timer
29 100
0:55 227.5 242.3 timer
29 100
1:00 228.8 234.3 timer
29 100
1:05 228.5 217.4 timer
0 100
1:10 225.3 194.5 timer
0 100
1:15 219.9 180.3 timer
0 100
1:20 213.5 171.6 timer
27 100
1:25 207.6 186.2 timer
58 100
1:30 205.1 214.6 timer
73 100
1:35 206.8 237.4 timer
74 100
1:40 211 252.6 timer
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1:45 215.4 259.6 timer
55 100
1:50 220.8 260.4 timer
48 100
1:55 225.1 255.5 timer
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2:00 228.6 251.3 timer
47 100
2:05 231.6 248.8 timer
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2:10 234.5 248.9 timer
50 100
2:15 236 250.7 timer
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2:20 238.3 256.4 timer
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2:25 240.5 261.2 timer
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2:30 242.6 268.4 timer
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2:50 255 279.2 timer
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3:00 260.3 286.8 timer
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3:05 263.3 290.2 timer
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3:25 274.6 297.9 timer
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3:40 283 310.6 timer
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3:45 286.2 314.2 timer
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3:55 290.2 321.2 timer
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4:00 293.8 328.4 timer
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4:05 297.1 329.2 timer
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4:15 303.1 330 timer
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4:20 305.9 327.5 timer
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4:30 307.6 331 timer
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4:40 310.6 338.6 timer
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4:45 313.2 340 timer
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4:50 315.2 338.6 timer
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4:55 317.3 340.4 timer
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5:00 318.2 340.5 timer
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5:05 320 341.9 timer
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5:15 322.6 346 timer
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5:20 324.5 350.5 timer
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5:35 329.9 358.5 timer
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5:45 333.3 360.6 timer
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5:55 337.7 361.1 timer
73 100
6:00 340.1 362 timer
64 90
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6:15 344.6 367 timer
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8:00 379 406.9 timer
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8:05 381 405.4 timer
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11:30 416.8 427 timer
0 75
11:33 417.4 408.1

BenKeith wrote:Not sure what you would even consider buying in an air roaster that roast 120-200 grams of beans that might even come close to matching the performance of mine, but you can bet your sweet ars that SR-700 won't come close. You can't "buy" a production air roaster the size of mine that gives the capabilities it has.
As for what kind is it, if you saw it just sitting on the bench, you would think it's just an old iRoast2 that has seen it's better days and just a piece of scrap sitting there. However, is like the old bootleggers car, looks can be deceiving, it ain't made to look fancy, it's made to go, and it will do that.

I'm going to try and get a roast in today and post a graph from RoastLogger if I can figure out how. I don't have one after redoing my process. The one I just roasted, I forgot to turn the auto heat control on the PID on for the first 1 1/2 minutes so it had a funky roller coaster right in the beginning, and was too cold in the garaged for my to do another, plus I was wanting to do more research on profiles for Guatemalan beans.

This is outdated information, for the most part. With the sr700 beta software I am able to set temperature within 10degree (and in 10degree increments, though a new member has been modifying the code and looks to have a way to narrow the margin of error considerably less than 10degrees) and have unlimited number of changes ranging from 1second-hours thus, I have developed profiles now that take bean temp from an initial charge of 190 and run it so that at 2:16 minutes I hit 212 4:30 hit end of dry 6:45 hit fist crack and 9min for the drop, or extend it as necessary all with a smoothly declining ror. I am on vacation but if you join the group you can see them, or if you want I can show you when I get home. Your setup is awesome and you have done incredible work, but the sr700 has a group dedicated to doing exactly this, and they have almost completed it, and are preparing to close the beta Facebook group and make the initial release.

Also, I have found that a cheap 5mm thick shielded probe, mounted in the top of the chaff chamber and extending just over the bean mass is giving a VERY consistent reading relative to the visual and auditory benchmarks. Mill city also carries probes short enough to mount just over the bean mass-or long enough to rest in in the beanmass, screwed in from the chaff collector, with a 2mm thick shield-but they cost 5x as much. No doubt would be more sensitive to changes in bt though. Mine has been consistent enough, but I bookmarked the page just incase. I also found that bare wire probes had a number of problems inthis style roaster, but still use a bare wire for et.