I just wanted to introduce myself. My name is Eric, I've been home roasting for around 11 years now, and I got into espresso just a few months ago. I also recently built a new roaster to up my game a bit, both in batch size and automation/profiling. My old roaster was also home built, but I got rid of the connectivity to Artisan about 7 years ago, so my ability to learn from my previous roasts has been pretty limited in recent years. I'm definitely still learning quite a bit, but I've enjoyed lurking on the discussion here on HB, so I figured I'd jump in.

My rig is a 1kg capacity fluid bed air roaster. Fan and heat can be controlled by either the manual controls, or through Artisan. Once I start honing in the roasts I really like, I'd like to automate those profiles in the future. A smaller 1/2lb roast chamber is in the works as well, for easier sample roasting.



I see that quite a few folks here use drums, so I'll be interested to see what does and doesn't translate in our experiences. I'm sure most of it will.

Anyway, just wanted to say hi. Thanks for having me, and I look forward to participating in the coming months.

Awesome! Welcome!

What is the heat source in that well crafted box of yours? Dryer element?

Thank you!

It has two 2200w heat gun elements running in parallel. I measured the voltage and current at full blast the other day, and it looks like I'm getting a nice even 4.5kw of heat at 100%. I haven't needed all of it yet, even with 1kg of green.

I have a build thread over on homeroasters.org right here:
https://homeroasters.org/forum/viewthre ... ad_id=6907

A video clip of the roaster in operation would be awesome. Curious if the beans toss around ala FreshRoast, or spin ala IKAWA...

Erichimedes wrote: I also recently built a new roaster to up my game a bit, both in batch size and automation/profiling.

Have you seen this thread? The New Roaster

Here's a clip from earlier when I was doing testing. Usually the fan is up more and the beans blow a bit higher.
http://www.youtube.com/watch?v=J-X8-2iCdFg
There's a central bean spout, and the beans return down the sides, so it's basically a toroidal shape. This lets me use a thermocouple one side, getting a fairly accurate BT reading. The swirling designs are cool, but BT thermocouple location is a pain because the hot air is passing up the sides.

I have seen that thread, CK makes a mean roaster! Would love to know more about the technical aspects of it.

Anyone else here using an air roaster, and also using Artisan to log their roasts? I'm curious to compare roast profiles. Some of mine look a lot different than drum roaster profiles, and I'm just wondering if other folks with air roasters try to mimic drum profiles or not. I certainly can, but this roaster doesn't do it naturally, you have to meter heat very specifically to get it.

Very impressive job. Thank you for including the linked thread which such a detailed account and photos of the construction process. Quite inspirational for folks like me who are thinking of attempting a home built roaster.

Did you start roasting on a home built machine?

You mentioned a previous home built roaster, I would love to hear more about it. How long did you use it before deciding to upgrade?

I started out - and remain on a modified West Bend Poppery 1 (heat & fan switch seperated, kitchern thermometer side mounted in middle of chamber). Thinking of doing a Frankenroaster but still figuring out what I want to change or improve upon.

Sounds basic but I have learned that there can be a different between what you think you want...versus the reality. Pus I am still deciding whether to build 'from scratch' or modify an existing machine.

For example an air fryer might be fun to modify into a coffee roaster. Given my lack of mechanical skills, I probably will end opt for this option as opposed to building from scratch. My very mechanically inclined husband has offered to help...but he busy with several projects around the farm at the moment.

For example, I would like a larger roast chamber but am undecided on material: glass or steel? Open or closed roast chamber? Any change in roast chamber design and/or material will impact roasting profile which needs to be considered.

Being a creature of habit I am inclined to replicate the WB Popper 1, in my case with an open top (removed the plastic chute) which allows me to hear the roast progress. Having said that, a glass roast chamber is appealing for better visual observation....but worry about not being able to hear First Crack.

Welcome and thank you for sharing such a beautiful and inspiring roaster.

Erichimedes wrote:Here's a clip from earlier when I was doing testing. Usually the fan is up more and the beans blow a bit higher.
video
There's a central bean spout, and the beans return down the sides, so it's basically a toroidal shape. This lets me use a thermocouple one side, getting a fairly accurate BT reading. The swirling designs are cool, but BT thermocouple location is a pain because the hot air is passing up the sides.

Thanks for the video link - that machine belongs in the storefront window of an artisan roasting shop

I understand that it's a pain, but it might be instructive to (at least temporarily) place two thermocouples: one inside the central air stream, and another placed low and along the outer wall of the chamber. That way you can measure the max/min temperature of the beans as they circulate in the chamber. The oscillation in bean temperature isn't necessarily a bad thing, as I suspect that might be similar to drum roasters, where the beans alternately contact the drum walls during the roast, essentially 'pulsing' heat into the greens - that might be a key element to drum roasting magic.

Erichimedes wrote:... I'm just wondering if other folks with air roasters try to mimic drum profiles or not. I certainly can, but this roaster doesn't do it naturally, you have to meter heat very specifically to get it.

Oh, heck yeah: IKAWA Home - profiles

I eventually 'did the math' and came up with a profile calculator to emulate drum roasting profiles: IKAWA inlet profile calculator The calculated setpoints could theoretically be ported to any other fluid-bed roaster, like yours.

I decided to punt on trying to copy the thermal dip when the beans are loaded into a drum roaster, on the theory that what happens below around 100C doesn't make that much of a difference. So, I start curve-matching at the "turning point" in a drum roasting profile. It turns out to be pretty easy if your air roaster has a tight PID control loop and enough airflow to thermally saturate the greens.

Mary,
Thank you! I also started out on a modified popper, and it really got me a long way, I loved that roaster. I saw a popper in the thrift store the other day, and it took some self control not to buy it for parts After that, I built a 1/2lb roaster with a TC4 that I used for a couple years, but it eventually fell off the back of my deck (long story, my best friend still feels terrible about it, haha) and I had to rebuild it. When I did, I left out the TC4 because I was losing interest in always having my laptop attached to roast. So the guts of that roaster lasted 10 years, and they're still working great actually. I'm planning on rebuilding it AGAIN into a new more professional enclosure, and then just selling it on now that I have this one. I've been wanting to make a new roaster for a long time, but until about 3 years ago we lived in a house with only 120v circuits, and that really limited what I could make. Also my fabrication skills and available tools are better now than they ever have been, so that's part of it.

Building roasters is fun! It's a ton of work though, even with all the right tools and skills. As you can see from my thread over on homeroasters, I screwed up the roast chamber on the first go around, it wasn't nearly big enough. It takes a lot of time to research everything and make the right decisions the first time around. I'm a big fan of modifying readily available things too, and that's usually a smarter move in terms of time and money. I would imagine you could hotrod an SR800 into a pretty capable machine with not a ton of work. Add thermocouples, maybe integrate heater control, I don't know.

Gary,
Yeah, it's interesting, I played around a lot with a loose thermocouple back when I built my first roaster, just trying out different parts of the air stream, bean mass, and depth of the roast chamber. The temperature in the bean spout itself is so far thrown off by the incoming hot air, I was never able to glean much information about the BT from it. One of the reasons I like the central spout is it gives me the sides to work with where I can have a thermocouple that just has the returning beans sliding over it, giving me a pretty good temperature to work off of. On this roaster I'm trying a bare thermocouple BT probe for the first time, and it's really interesting. Lots more noise than a sleeved TC, but it feels like I'm getting a very accurate temperature right away. Everything reads hotter, most beans hit FC at 395-398 F (sorry, I started with F and can't switch my mind to C).

I have a design sketched out of a roast chamber that blows the air up the sides rather than middle. Basically still a toroidal bean mass, but rotating the opposite direction. Not sure if I'll ever build it though, my gut feeling tells me that it would require quite a bit more fan speed, and be more sensitive changing the charge size. Swirling roast chamber designs are awesome, but they really don't scale well above about a 1/2lb charge. But since it's so easy to swap out the roast chamber on my machine, I can make whatever I get a wild hair to try. What I really want to do is make a perforated drum assembly that uses this roaster as it's heat source, to mimic a Loring or IMF type roaster, but that project will probably need to wait until this winter.

Thanks for pointing me to that thread about roast profiles! Awesome info. I'm just now starting to use PID through Artisan to control my roasts, so I need all the tips I can get. It's working fairly well though, I'm going with the PID reading from the ET probe approach, and I like it so far. As soon as I finish my smaller 1/2lb roast chamber it will be much easier to do testing, since the smallest charge I can do right now is 1lb. Hoping to have that chamber finished in the next week or so.

So excited to participate within this community. One skill I really need to hone is cupping. My palate is... I don't know, experienced? but not what I would call refined. I've never put any of it into words or conversed about it with other roasters, so I'd really like to get better at that. I got in on just a couple pounds of the Tanzania Gesha lot being distributed by Boldjava, so I'm going to participate with that as best I can.