Home-Barista.com

Almico wrote:Coffee roasting is not something that benefits from automation; at least as far as optimum flavor goes.

I completely agree with you today. Roasting coffee (and extracting it) is still way more art than science.

However, my comment was related to a direction that I expect things will go. In 20 years, it is possible this balance will have flipped.

Apologies to the OP, think we might be off track!

I've owned both, as well as a huky, and nearly every other home roaster....

The bullet is king. Can you roast great coffee on the quest? of course. Is the usability and opportunity to repeat roasts consistently on the bullet better? Without question.

The quest was frustrating to use at times but I really liked that little guy for the price.

The Aillio still has a BT probe in addition to the ITBS that you can monitor if you prefer.

You are very lucky guys to have this roaster! In Europe, it's difficult to buy.

Personally (as my quoted post above says) I was pleasantly surprised by the coffee I'm getting from the Bullet. With the Quest M3s I was getting what I wanted, and my goal was to be able to roast larger batches with the Bullet and match what the Quest did. What I find is that the Bullet's higher power brings my roasts into a slightly "sweeter" spot, and I am quite happy with that. With the Quest I was roasting 8 ounces, with the Bullet I am roasting 16 ounces and getting comparable or better results. I have found that a lot of the tweaking of drum heat, fan speed, etc. that many Bullet users seem to be using is not the way I want to roast. I'm much more of a "keep it simple" person. Finding the right preheat temperature seems to be the most important factor. I also find that the Bullet's IBTS (IR Bean Temp sensor) seems to be a very close match to the temperatures I got with the bean temp thermocouple on the Quest; for example I'm hitting FC at nearly the same temp, give or take 2 C.

The Bullet is clearly a work in progress, with improvements being made pretty often. I'm very glad I waited until the IBTS was included. The software is a bit behind, but they are working on it.

One observation: there is some discussion about the Bullet's heating. From my observations, it does PID while pre-heating, and this is a big advantage to me, as I can set it to preheat and not have to watch it every second. (She'll even tell you when she's ready!) But once you add the beans and start the roast, it heats at the level selected - I do not see any evidence of PID or heat cycling on the power meter I keep in the circuit. The roast cycle is in this similar to the Quest's.

Will

I have a Quest M3s and I've come around on the Bullet R1. At some point when I want to upgrade to a larger capacity roaster, I think the Bullet R1 will be my choice. That's not to say the Quest isn't a great little roaster, because it is, but the 1/2 pound capacity is really only suitable for my wife and I. I continually turn down friends and family because I just don't have the time.

[creative nickname] wrote:In my experience you get better results by steering a roaster proactively, and living with the results, rather than trying to overcompensate for what has already happened as a roast is in progress.

I really like this.

FWIW, the discussion about IR probes is way off.

1) All digital sensors must use "an algorithm" to read values. A thermocouple does not just send back raw temperature numbers to the computer, it sends back voltage readings that then must be converted to temperatures. The IR sensor driver code is almost identical to one from a thermocouple code since the vast majority of code used has more to do with bit twiddling than anything else. You don't have to take my word for it though, just look at this open source driver for arduino: https://github.com/sparkfun/SparkFun_ML ... X90614.cpp

To be very clear, IR sensors provide definite latency gains compared with similarly priced/quality thermocouples. Light travels much much faster than a sheath of metal changes temperature.

2) The concerns about emissivity and background temps of the IR probes strikes me as incredibly pedantic even for HB. Very simple IR thermometers that cost under $10 have no problem detecting the temperature of random items to a high degree of accuracy, I see no reason why the IR probe in the bullet can't do the same. IR technology has been around for a while now and is largely a solved problem for most problems of a reasonable scale. The IR probe is not perfect and will have its own difficulties, problems, nuances, and quirks, but most of the concerns in here seem unfounded. By far the #1 issue with IR is emissivity calibration, and Aillio seems to have solved that issue well enough. Here is a thread where Jonas addressed many questions (including my own that were in the same vein as some asked here, although I was more curious than critical) about the IR probe: Aillio Infrared Bean Temperature Sensor IBTS

3) The IR probe is definitely tricky to get used to, but I think once I get a handle on it I'll be able to make much better decisions about roast adjustments than I was with a 3mm probe. My own personal experience has shown it to be remarkably accurate for yellowing, FC, and 2C temps largely regardless of environmental factors.

false1001 wrote: 2) The concerns about emissivity and background temps of the IR probes strikes me as incredibly pedantic even for HB. Very simple IR thermometers that cost under $10 have no problem detecting the temperature of random items to a high degree of accuracy, I see no reason why the IR probe in the bullet can't do the same.

Maybe you should read up on how IR sensors measure temperature. The link here has some information on background correction: https://www.apogeeinstruments.com/conte ... ection.pdf

I've plotted inaccuracies with different emissivities and background temperatures. If your cheap IR sensor is measuring something with emissivity of 0.8 at 100F when background is 70F, the error is only around 5degrees and likely could be better corrected with a simple algorithm knowing the emissivity. However, in a drum roaster at first crack, the drum is 500F (at least that is what my North 1K is). This is a huge IR source shining like the sun at the beans. With that high of temperature, something with emissivity of 0.8 at 300F will be off over 80 degrees! With emissivity correction, it is less but still way off. If you assume a background temperature, you may get closer. I have not measured coffee, it may not have an emissivity as good as 0.8, meaning temperature could be off even more. And are all beans the same independent of level of roast? To get accuracy within a very hot drum without knowing how hot the background and what the emissivity measures isn't possible.
But maybe they are somehow measuring drum/background temps with a second IR and have a good estimate of bean emissivity.
Two IR spectrum measurements I believe can deembed the emissivity. Are they doing this? My $70 Phidgets sensor sure isn't.