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Dan's Direct-Flame Roaster
seedlings
Youtube has lifted the 10 minute limit. Post away, Dan!

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
coffeeroastersclub

Quote

Dan wrote:
Hey, maybe I could post a video on YouTube. Does anyone know if I have to do something special to make my camera's MOV file work/compress for YouTube?


Dan,

Any luck with the movie yet?

On another note, if your design works well you should think about marketing it. It looks nice and clean, and simple to use. Also it has a unique "out of the box" type thinking in its design ThumbsUp. The industry needs more of this stuff, instead of the same old same old.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
Dan
I brought the camera home for the weekend, so I hope to get something soon. I want to include the flame action, too.

I'm OK with people copying it, but I don't need another business to run!
 
Dan
I've mentioned before that my pet roasting theory is thus: The best flavor comes from beans that have been roasted on-the-heat and off-the-heat. My rational is this. If on moderate heat constantly, like in a convection oven, it results in flat, baked flavors. Conversely, all roasting methods have a certain degree of hot and not-so-hot zones that the beans pass through. Therefore, beans need to go from high heat, to something less than high heat, and back again. Just like in a rotiserie where the roast passes by searing heat about one-third of the time, and reduced heat for the remainder.

This theory is why I grabbed onto the idea of trying direct-flame roasting. A small portion of the beans pass through VERY high heat, and then go to significantly reduced heat until the pass through the flame again. If I'm right, it should produce great flavor, and one historical account supports this claim.

I just tested my prototype roaster loaded with 1400 grams of green. For every vane, 62 grams pass through the flame. That's 4.4% of the load. Durng one minute, 33% of the bean pass through the flame, meaning that for any given bean, it is passing through the flame once every three minutes.

The reason I'm going on and on about these ratios is that I think it is important. I don't know if the ratios in my machine are optimal. They probably aren't. But I do think that further investigation will reveal an optimal ratio. Just like we've discovered the narrow range of what works in hot air roaster's perf plates.
 
JETROASTER
I stumbled across a patent a while back. It was for a piece of food process equipment. The authors specifically wanted the "heat and rest" cycle. They felt the "rest" period was important to allow moisture to stabilize during the process.
It sure sounded convincing! Looking forward to your tests. -Scott
 
Dan
Scott, that's very interesting. "Heat and rest" is a good way to describe it.

I just finished my first flame roast. I'm still winded from what had to have looked to a bystander like a clown trying to bail the ocean with a teacup! I thought I was prepared. That's the last time I use a mental check list.

I put the roaster on a rolling workbench and wheeled it out on my shop garage door apron, then leveled and chocked the wheels. I got the torch lit and turned it up 100%, but it kept blowing itself out when stuck in the drum. Seems the exhaust fumes would circle back and blow out the flame from lack of oxygen. I think the prevailing breeze worked against me, too. But, when I reduced the flame to about 1/2, and pulled it out of the drum about 2", it stabilzed.

At that point I turned on the drum holding 3# of organic Mexican beans. Almost immedicately I began to smell drying phase aromas. I wondered if the flame was too hot. The wind picked up and the flame blew out; relight it. Out again, and again. Ran and got a half sheet of plywood to block the breeze and that worked. Forgot to get my TC thermometer, ran for it, took an ET at the bottom of the drum at 3 minutes, about 340?. Seemed just right. Then the vibration loosened the chocks and the whole rig rolled off the leveling blocks. I thought it was going to flip over, but it stopped somehow on its own. I reset the blocks, and ran inside for something to weigh down the chocks, ran back, put that weight in place, decided I needed another weight, and repeated that jog.

Took the ET again, and it was settling at 530?. I never heard first crack, but perhaps I was inside. I heard second crack and realized I didn't have a cooling tray rigged up. How could I not remember to do that? Ran inside and grabbed it and jury rigged a support. They second crack began to roll and smoke was beginning to come from the roaster. So I decided to dump it. At that point I realized I didn't have any gloves! Dang. Ran back inside and couldn't find any gloves in the shop. Strange. Grabbed a shop rag instead. I took a look at the roast and it seem very dark, but then the lighting was poor. I roast a lot from smell, and this smelled like I was about to lose the roast, so had to hurry. I gingerly grabbed the drum by the tail shaft and poured it into the cooling tray. The color was gorgeous! Even though the smell and cracks said it should be a FC or FC+, it looked like City+.

In my research on flame roasting I ran across and interesting item. A roaster said that the shorter the roasting time the longer the cooling time to compensate. Apparently, it gives some of the chemistry time to finish. This certainly makes sense if you want to reduce bitter trigonollene. So, I didn't fan force the cooling. Besides, that would mean another run inside! I stirred the beans occasionally and let the 1" think mass cool naturally. That took about 12 minutes. Interestingly, I didn't see any divits. Tomorrow, my first taste test.
Edited by Dan on 05/30/2011 3:02 PM
 
seedlings
I was on the edge of my seat that entire post! Nice, Dan!

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
coffeeroastersclub

Quote

Dan wrote:
Scott, that's very interesting. "Heat and rest" is a good way to describe it.

I just finished my first flame roast. I'm still winded from what had to have looked to a bystander like a clown trying to bail the ocean with a teacup! I thought I was prepared. That's the last time I use a mental check list.

I put the roaster on a rolling workbench and wheeled it out on my shop garage door apron, then leveled and chocked the wheels. I got the torch lit and turned it up 100%, but it kept blowing itself out when stuck in the drum. Seems the exhaust fumes would circle back and blow out the flame from lack of oxygen. I think the prevailing breeze worked against me, too. But, when I reduced the flame to about 1/2, and pulled it out of the drum about 2", it stabilzed.


I've witnessed these scenarios on my own R&D roasting exploits! Shock

Here's a question: Does your flame thrower have air cutouts on the back of the burner? I know that some do, and some don't. I have one that does (got it at harbor freight). If yours doesn't, maybe that can be a fix for the oxygen deprivation?

Len
Edited by coffeeroastersclub on 05/30/2011 3:27 PM
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
Dan
Chad, I truly expected that first roast to go to the dreaded third crack as soon as I realized I wasn't prepared. I was surprised that it turned out OK. I thought I'd have to throw away the first few roasts. But then the jury is still out on this first batch until I taste it.

Len, I'm using a Sievert torch. It has air intakes at the back of the burner, making it a venture type of burner. I have to think that they engineered it correctly, and that I was using it wrong. It worked fine once I got everything adjusted OK. What I think was happening was the combustion gases in the drum were circling back outside and getting sucked back into the torch, but of course a lot of the oxygen was already used up.
forum.homeroasters.org/forum/attachments/sievert_294202.jpg
Edited by Dan on 05/30/2011 3:47 PM
 
JETROASTER

Quote

Dan wrote:
Tomorrow, my first taste test.


OK...any first impressions? -Scott
 
Dan
I thought I'd post tomorrow, after the third day to give it a decent chance. :)
 
coffeeroastersclub

Quote

Dan wrote:
I thought I'd post tomorrow, after the third day to give it a decent chance. :)


Man, you're teasing us! :)

Were you able to get any vids put up?

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
Dan
Teasing about this coffee? Man, I'm confused about this coffee!

To be fair, I gave it three days to rest. It's a light roast, so it probably needs more. Here's my confusion. While roasting, I heard what I thought was the beginning of second crack, or being in Full City. Today, the color looks like City, but the ground coffee looked like American.

Two weeks ago I happened to roast some of this same bean to FC+ in my sample roaster, so I have that recent memory as a comparison. Recall that I didn't expect this first flame-roast to actual be drinkable, so I didn't bother to create a side-by-side taste test, but here goes my initial report:

This coffee tastes bright, so I think its real roast level is City or City-. There are no odd or off flavors, so I can definitely say that flame roasting does not make terrible coffee. The coffee was tasty, and had the same body, aroma, and origin flavors I recalled from the FC+ roast I mentioned. However, I cannot yet say that flame-roasting produces a better tasting cup than other methods, which you will recall was the claim its proponents made.

Clearly, some more tests are in order. First, I need to learn more about using this machine, and perhaps figure out a way to take BM temps. Second, side-by-side tests are warranted, preferrably blind. Third, at some point I'd like to send out some samples for people to compare. I wish I could report more, but I cannot.

 
JETROASTER
After the hilarious tale of the first run....I wasn't expecting your best work! Are you sure you're not hiding the video of that?
It just sounds like it was just a bit fast. Great first run. No fires, no injuries. Cheers,-Scott
 
JETROASTER
A quick assumption about this machine; It seems to me that turning down the heat will have an immediate impact vs. the coast-down of a traditional drum....? -Scott
 
Dan
Scott, I think its too soon to say anything other than yes, it does roast coffee. I didn't make a video, I had my hands full! Perhaps this weekend.

My 8kW burner was set on about 2/3 heat, so maybe 5kW output. Direct-flame roasters are known to roast quickly. I think some tests need to be done to figure out what an optimal profile might be.

Wow, a hidden design feature! You are right, once you turn the burner off there isn't much residual heat in that drum and the load should cool quickly. With that in mind, I'm going to try drum cooling. With the drum aerating the beans and all those vent holes in the drum, it should cool down quickly. That would be great, it would mean I don't need a cooler. :Clap:
Edited by Dan on 06/02/2011 3:33 PM
 
Dan
I finally got a chance to do my second roast. This time wasn't as hectic as the first, but it still had some excitement. The set screw on the main driver sprocket kept coming loose. Four times I had to shut off the burner, remove the drum and tighten it. I feared I would have a stalled roast, especially since the last time was during second crack.

The good news is that I'm already feeling more comfortable with adjusting the burner. But then I used my electric sample roaster for a year using its percentage timer control that works just like a gas valve.

What I do know is that flame roasting produces gorgeous looking beans! I think it has to do with searing.

The Brazilian Cachoeiri Yellow Bourbon has only rested 20 hours after its Full City roast. The coffee tastes young, and needs to rest more. As the cup cooled I got great hazelnut flavors and a crisp cup. None of the smokiness you get from an enclosed drum roaster. Great body, too.

I'll make a video after I get the bugs worked out.
 
JETROASTER
Sounds like it's getting less stressfull !!
How long did it take to get the Brazilian Cachoeiri to Full City? -Scott
 
Dan
That's a good question, Scott. I was tracking the time and BT, but when things were gong haywire I stopped. Next time I should have a profile to post.
 
allenb
Dan, I think a lot of us here would have paid money to see a video of the first two roasting sessions. I think you could have sold them to companies to use in their damage control training classes!Grin

All kidding aside, hearing you describe the Brazil roast characteristics has me chompin at the bit to put a direct flame model together to experience it first hand, not necessarily the damage control part of it but that comes with any new design. Keep plugging away on it because I think it's going to be a keeper.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Beaner
Pity there's no vid of the first attempt. Dub some Benny Hill music on it and you got yerself a hit.

ThumbsUp
 
Dan
LOL! Fire and mortal danger. It's part of the lure of the hobby, right! In both roasts I could have just stopped when the first problem arose, but the desire to save the roast was too great. Therein lies the humor, I think.

My grandson said the drum with handle looked like an eyeball, and since it has a flame in the middle, we now call it the "Flaming Eyeball Roaster"

I'm already designing my second machine based on what I have learned. First, those large mixing bowls are GREAT! What an easy way to make the perfect drum for a direct-flame roaster. Next time I want to go direct-drive and just use idler wheels to support the drum. It will be quieter than the rattle-rattle of the sprocket drive amplified by bowls.

That Brazilian was tasting great, today!

 
JETROASTER
Any updates? -Scott
 
Dan
Just this morning I was thinking I'd drag it out and try a roast. It's kinda windy, so I'll have to figure out a better windscreen.
 
Dan
Here's a link to a QuickTime video of the roaster in action. The flame wants to blow out, probably from drafts. You hear how noisy the chain drive is and how jerky the mechanism is, too. Next time it will be direct drive.

http://claycritte...aster1.mov
 
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