Vicki, Ryan: I was curious also about whether the iR2 would decrease the temperature after the override period so I entered Ryan's 15 minute profile and roasted some Columbian Huila San Jose de Isnos. The results appear to be pretty much a disaster. The roaster did not reduce the temperature after the default period. Not only that, but it never increased the temperature when the 2nd stage program called for 330F, so basically it maintained 350 indicated for 9:45, ending stage 2 with a thermocouple reading of 394F. Stage 3 maintained an indicated temperature of 367, taking the beans to 410F at the end of the 4:15, the final stage maintained an indicated temperature of 376F, and took the beans up to only 416F. My thermocouple reads 435F for a C+ (or so) roast, so this came out extremely light, uneven and only about half the beans appear to have completed 1st crack. I will be interested to see what they taste like. I'm thinking it's gonna be baked, big time. So it appears that as reported, the iRoast machines are very inconsistent, one from another, and in my case at least, no, the machine does not drop the temperature down to the programmed temp if it is lower than the default stage. It also appears that the machine either: 1. ignores program increases of less than some amount, or 2. has some unknown break points that your program temp has to fall between, or 3. has some unknown break points that it can control to. Indicated (LCD readout) and ThermoCouple readings at 30 sec intervals: Time Ind TC Prog 320F 0:30 291 175 1:00 325 245 1:30 342 289 2:00 352 314 2:30 350 331 3:00 350 345 3:30 350 355 4:00 352 361 4:30 350 366 5:00 350 372 5:30 352 376 6:00 352 381 6:30 350 383 7:00 350 388 Prog 330F 7:30 350 389 8:00 350 389 8:30 352 391 9:00 356 391 9:30 350 391 9:45 352 394 Prog 350F 10:00 367 396 10:30 367 400 11:00 365 403 11:30 367 405 12:00 367 406 12:30 365 408 13:00 367 409 13:30 365 410 14:00 367 410 Prog 365F 14:30 376 414 15:00 376 416 This is not a big disappointment for me, I'm currently pretty happy with my 8:30 to 12:00 roasts to C+ - FC or so. I just wanted to know what my machine would do and find out how much variation there is between machines. Looks like there's a lot! Michael Wade
Hi Michael, I was pretty sure Ryan's profile wouldn't be a good one for my machine either. So far the ones that work best for my machine seem to start at 350, increase (or decrease) by at least 20-25 degrees for each step, and have at least 2 minutes on any one step. A decrease seem to need at least 3 minutes to really change the way the roast develops. I know they are all different, but these general guidelines seem to work for my IR2. I'm also finding that roast size makes a huge difference. I would assume that smaller bean masses are more responsive to changes in temperature settings, with bigger batches holding on to heat and developing more heat regardless of any small changes I make. vicki Michael Wade wrote: <Snip>
My two iRoasts (orig. and 2) are like night & day. The original one runs so hot that even with a long extension cord, it'll overheat and shut off if I use one of the presets--or even program a multi-stage roast too hot. The 2 runs very true to temp and has always done well with both the presets--only time it ever overheated and shut off was with that disastrous load of fermented JBM greens from a non-SM vendor (they were so heavy that they did not circulate well, allowing heat to build up in the bean mass to the shutoff point). And I have yet to stall a roast in it yet--I even nearly did that in the SC/TO with some Harar Horse Lot 30 when I turned the heat down to 350 too soon (but I added 5 min. at 450 and saved the day). On Jul 2, 2006, at 6:53 PM, Michael Wade wrote: <Snip> Sandy Andina www.sandyandina.com
Michael, FWIW, your indicated temperatures for programmed temperatures of 350F and 365F match mine exactly. I do not have any records from my attempts to go below 350F. I have managed higher starting temperatures. A programmed temperature of 455F for the first five minutes resulted in an indicated temperature of 430F. From your results using Ryan's profile, and without any supporting measurements of my own, perhaps 350F is the minimum allowed temperature for the entire profile with some variation due to input voltage. My household voltage is typically 127 volts, which is a bit high. I would complain to my electric company, but that is who I work for. I think someone on CoffeeGeek mentioned that the iRoast heating element only has three temperatures (low, medium, and high), with the fan providing the remaining temperature control. Assuming two or three possible fan speeds, that would give 6 or 9 achievable temperatures, including the minimum and the maximum. On Jul 2, 2006, at 5:53 PM, Michael Wade wrote: <Snip>
Hi Vicki, <Snip> IMO, the machine is very temperature-agile on temperature increases. If it is so inclined, it can raise the bean mass temperature pretty rapidly, but I am beginning to think of it as having the spirit of a cat. It is touch and go whether it will feel like cooperating on any given day. It was not the least bit interested in Ryan's profile. The only time I've tried a decrease was when I was roasting a fast profile and programmed a finish stage of 355 that acted as a slow cooldown to make sure the beans were temperature soaked all the way through. You're right, it took a while to get the bean mass temp down. <Snip> I always use a weighed batch of 130 grams, simply because that fits in my clamp-top glass canning jars and eliminates a variable. I roasted several batches today besides the 15 minute test, and I (finally!) like what I'm seeing in terms having some control of roast depth, at least at C+. I am impatient (never a productive learning atmosphere) to get enough confidence to try roasting some of the Triple-Pack that I bought. Maybe later this month. The whole house smells like coffee. I love it! Michael
Sandy, <Snip> Oh, I remember that story. I've always wondered what those beans were coated with or soaked in, and for what purpose. Ever figure that out? Michael
David, <Snip> Whaddya know, at least two of them are close! <Snip> Even for the first couple of minutes? When I program something like 400F for the first 5 minutes, the machine won't go over 350 for some indefinite period. I've seen it last as little as 1:50 or as long as 2:50. <Snip> That was an unexpected result, for sure. Not only did the machine not track the programmed temp after the default was satisfied, but either the 10F increment was not sufficient to get the control program's attention or there is some predetermined temperature point that the processor is looking for before ratcheting up the controlled temperature. Maybe 11F, or 13, or 15 would have done the trick. I'm not feeling ambitious enough to design a series of tests to find out. I hadn't thought about it being related to line voltage. I just went out and checke the appliance receptacle that I use for roasting; it's 122.9V open circuit, and 121.4V loaded by a toaster. seems OK. But you would know better than I! <Snip> <Snip> That's interesting. I'll have to do an exploratory. Did they say whether there are multiple elements that are switched in and out, or any guess as to how the heat is controlled? I would think that anything other than switching would be prohibitively expensive. Given the undocumented default override and the apparent inconsistency between machines I have to wonder what other undocumented changes have been incorporated between (or even during) production runs. It woujld be interesting if we could somehow find the production date for our respective machines and correlate that with the other symptoms. Then again, sufficient unto each day the evil thereof... don't go looking for trouble. Michael
This is the profile I find myself using most often: 350 3 minutes 375 2 minutes 425 3 minutes 450 3 minutes I think one of the reasons it works so well for me is that the fan speed changes almost exactly (mebbe a 10-15 second lag)when the temperature changes kick in. Yesterday I roasted 150 grams to City+ and stopped the roast with 2' 15" remaining. That seems pretty typical, regardless of the beans (within 15-20 seconds). This profile gets me to Vienna (as far as I have ever gone) with between 45 seconds and one minute remaining, depending on the bean. Bigger batches (150 grams) take longer to get to first crack, but the total time elapsed is about the same as roasts that start with 130 grams. The difference between batch sizes is that with 130 grams the time between 1st and 2nd crack is longer. What I would like to do next is setup a profile that increases the time at step 2 or step 3 see if I can prolong the time between first and second crack a bit. I somehow think that perhaps because of the size of the roast chamber vis-a-vis the bean mass, this is less doable than it might appear, I'm very satisfied with the roasts I am getting, but I wonder if I couldn't get a little extra magic if I could do that. Vicki !*!*!*!*!*!*!*!**!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!* Taming Coffee: The Weblog http://taming.motime.comMichael Wade wrote: <Snip>
On Jul 3, 2006, at 1:45 AM, Michael Wade wrote: <Snip> The ramp took about 1 minute. The machine was at 430F at one minute and it settled to 433F at two minutes. I used this profile several times early on, but I only have one set of measurements. <Snip> Given what I have seen from using this machine, I think the limited- number-of-available-temperatures idea is the correct one. I have a lot of strange profiles that bear this out, but something else may happen that makes me change my mind. If this idea is correct, then the temperature you end up with depends on where the programmed temperature falls in relation to one of the available temperatures and the slop in the controller. On my machine, programmed temperatures of 350F and 360F both result in indicated temperatures of 367F, but a programmed temperature of 365F gives me an indicated temperature of 376F. So the trick to programming the iRoast is to find out what the available temperatures are and then set the program to hit those temperatures while not worrying about the differences between what is programmed and what is indicated. Your voltage measurement is interesting. I was concerned that my 127 volts was causing the machine to run hot. That seems not to be the case, and I can avoid buying a variac.
Vicki, What indicated temperatures do you get with this profile, with the measurements taken at least every 30 seconds? On Jul 3, 2006, at 6:40 AM, Vicki Smith wrote: <Snip>
Sorry, David. I never took 30 second outlet temps, and now with my machine behaving oddly, I can't duplicate this any more. The shame of it all, is that if Hearthware decides to replace the machine, chances are it won't duplicate it either. The machines seem incredibly variable. The minute temps were pretty much spot on, though stage 3 ended at 320, and I never roasted all the way to the end of stage 4. Had I known my machine would go flaky, I would have taken more frequent measurements. I might have a relative lack of multi-tasking ability, but I found that when I tried to take more frequent temps, I couldn't concentrate on the other things I was trying to attend to--the whole sounds, sight, smell thing. Vicki David Schooley wrote: <Snip>
On Jul 5, 2006, at 5:24 PM, Vicki Smith wrote: <Snip> The advantage of 30-second measurements is that you have some slack if your transitions between stages also occur on one-minute intervals. I have found that the machine takes a minute or so for the temperature to settle during the first stage. The transitions for the remaining stages take 15 seconds or less. If you avoid sampling the temperatures during a transition from one stage to the next, then you should be fine. I use 15-second intervals because I like making graphs. Typing the numbers into a spreadsheet gives me something to do while the beans are cooling.