My prototype lpg roaster in an old lpg tank

[nissanneill]

Hi all,
just found this interesting forum as I have completed my prototype roaster a week ago, made with materials lying around with a little effort and the odd material purchased. Total cost around $24, I roast 250g per session but can increase this to 500g or more very easily, but prefer at this stage to do roasts as required, ie weekly.
Being new on here, I am unable to post pictures but will include them when permission is granted.
I have an ECM Technica III and an Iberital bur grinder for 3 years and enjoy fine fresh coffee.
Have roasted 4 batches with reasonable success, the first well underdone, and finding my feet now since repositioning the thermocouple nearer the drum rather than in the dome top.
Currently hand operated but can adapt a battery operated rotator, but resisting this as it is fun and able to see, hear and smell the process.
Will post my profile (temp and time chart) later.

Cheers.

Neill

[resonatorman]

Hi Neill, have you got some more details of this roaster you built? Look forward to reading some more on it & seeing some pics when you get the permission to post them, certainly sounds interesting for $24.....Enjoy your roasting journey it's certainly a lot of fun & rewarding.

Cheers

[JoeB]

+1 on pics. I have a couple of 40kg gas cylinders here laying around that I could use to roast beans. would be an interesting project!

[nissanneill]

I seem to be doing something different as I can only find a way to include pictures (or attachments) from a URL! and that confuses me. I want to attack photos from my desktop.
I will post pics once I work out how to guys!
However, let me explain the process.
I got a small out of date camping type lpg cylinder as I don't want nor need to roast large quantities of beans, initially intended to use a 9kg unit but ended up with a 7kg one. Firstly I ensured that was completely empty and no sign of gas before I cut it in halves around the welded joint line, cut a hole near the bottom to poke the ring burner shaft through allowing the ring to self centre in the hemispherical base. I also drilled some large holes around the base to allow for air inlet and after cutting off the brass tap on the top drilled it out and tapped a thread to take the temp probe. Had a flame trial run but after a minute or so it self extinguished, so had to lift the top section up to allow more air flow. All fine so made a mounting block on the 2 halves and bolted a substantial hinge allowing the top to flip over for access. Now I made a hexagonal basket deliberately out of thin perforated steel but later made a better one from 16g sheet with larger holes (as most of the chaff come off and out of the drum/basket and burn off)that hinged to allow easy loading and dumping of the beans, with a stainless shaft running through the centre with a hand crank on one side. I then cut 2 steel support brackets and welded them into the base to support the rotating basket then I had to cut a couple of grooves in the top section to allow it to close.
Time for a test roast!
I got a range of green beans from the green beans store (great people to deal with, good variety and prices with free delivery with orders over $50), put in 250g of $7/kg Indian Elk Hill Estate washed robusta beans and started roasting with the thermocouple up in the top of the dome at 230C. Not much happening after 20 minutes so I repositioned the probe the besides the basket. Tried with another 250g at 230C and it all happened, the top of the dome was now showing 560C, no wonder the first batch was not working.
Not a bad roast but a little burnt as I was waiting for the second crack, however there seemed to be only one long first crack, so in the bin!
Now to try some better beans but a little cooler, at 210C. Out comes the Kenyan AA Dorman beans and try a good batch. Pretty happy for a novice but room for improvement.
I am very happy with the roaster as it only takes around 10-12 minutes per batch and one batch a week is easy and enjoyable to do. I could fit comfortably 500g but don't have a need if i want to maintain 'fresh roasts in the cupboard.

There are pic on the Home roasters page which I found before this site which i prefer, hope I don't upset anyone with this link:

http://www.homeroasters.org/php/foru...thread_id=3199

Cheers.

Neill

[Javaphile]

I seem to be doing something different as I can only find a way to include pictures (or attachments) from a URL! and that confuses me. I want to attack photos from my desktop.

After making 5 posts you can attach pictures.


Java " " phile

[nissanneill]

Thanks for that information, couldn't find any details on the site.

Cheers.


Neill

[huez]

Im gonna use my first post on coffeesnobs to say you have inspired me! been thinking about making a roaster for awhile, looks the goods!

[nissanneill]

A very easy exercise to do, all you need is an old bottle, and angle iron, a drill to bolt things together if you don't have a welder, a vise to bend the basket and a good dose of common sense. The thermocouple is available from ebay at around $7 which plugs into a good multi meter.
The basket needs a little extra time and effort and once I get permission to post attachments, will post some pics on the basket detail.
Go for it!

Cheers.

Neill

PS. Just got approval and will take more pics so let me know what you need to show!

[nissanneill]

Had another roast yesterday, Kenyan AA Dorman beans in at 250g, out at 206g, beans almost twice volume and little overdone, not burnt but will be full of flavour. Removed at the commencement of smoke, what I now see as a good guide for my preferred roast.
Also playing with profiles, tried to keep roasting temperature to between 215 -220C to keep times reasonable.
See pice attached.
Also looking at a small rotator to free up one arm, and minor basket modification to view beans during roasting, looking for a small (50 x 50mm stainless woven mesh) in the end of the basket.

Neill

[Caneurysm]

Respect! That baby looks the goods, I am jealous of your tinkering abilities.

[nissanneill]

A few minor modifications, (looking at a reasonably fast rotator and a visual section to be added to the drum), a little more practice and I think that will do me. The results out of the unit are quite consistent, quick and according to the beans used, very tasty. I am now blending some of my different beans (at this stage, after roasting), but will now concentrate on blending them and then roasting.
The principle is good, materials easy to access and I feel that is a very easy and cheap roaster for the larger roasts, 2 to 5 kg for under $50.
My needs are around 200g/week so I have no intention to build big, rather keep the roasts small and the coffee fresh!!!!
The surprising thing with the last Kenyan beans was a 17.6% weight loss (from 250g and ending up at 206g) after roasting.


Neill

[Caneurysm]

A few minor modifications, (looking at a reasonably fast rotator and a visual section to be added to the drum), a little more practice and I think that will do me. The results out of the unit are quite consistent, quick and according to the beans used, very tasty. I am now blending some of my different beans (at this stage, after roasting), but will now concentrate on blending them and then roasting.
The principle is good, materials easy to access and I feel that is a very easy and cheap roaster for the larger roasts, 2 to 5 kg for under $50.
My needs are around 200g/week so I have no intention to build big, rather keep the roasts small and the coffee fresh!!!!
The surprising thing with the last Kenyan beans was a 17.6% weight loss (from 250g and ending up at 206g) after roasting.


Neill

I was under the impression from comments in other threads on this forum that 17-18% was an expected norm for a roast.

[nissanneill]

I was under the impression that 10-12% was the figure.
It doesn't worry me at all, the size of the beans is increased around 80%, the container of green n bean was exactly 250g and the 2 identical containers hold the 250g roast and almost doubled in volume.

Neill

[Vinitasse]

I was under the impression that 10-12% was the figure.
It doesn't worry me at all, the size of the beans is increased around 80%, the container of green n bean was exactly 250g and the 2 identical containers hold the 250g roast and almost doubled in volume.

Neill

I think you may have mixed up the "typical" moisture content of raw green coffee (around 12-ish percent) with the percentage of moisture loss during roasting (16-20 percent), all of which goes to say that the 17.6% that you experienced falls well within the "normal" range.