Cormorant vs Chinese roaster - Page 3

#21: Post by **hankua** » August 7th, 2022, 6:22 pm

The Taiwanese YangChia Feima roasters from 500g - 40kg have cast iron drums. I'm guessing the smaller ones are a single casting and others cast in sections? Also the composition of the cast iron can be adjusted at the foundry. This part of their manufacturing process is a trade secret.

August 7th, 2022, 8:12 pm

My 1kg BellaTW (made by Yang Chia) has multiple cast sections; there are two drum castings - one is a donut tacked in place around the main drum, and there is a separate two-part back casting (see pic below). Fin arms/spiders are also separate castings (no center axle in the drum). Faceplate and the main roaster supports are also cast iron, as is the air plenum/bean chute.

The roaster is friggin' heavy and takes its time warming up. I find it very easy to roast on compared to the Hottop (reverse airflow).

Regardless, material choices can be addressed by engineering, e.g., a double-wall drum can be designed to mimic cast iron.

Note that the colour balance is way off in this pic. The rusty-looking out-of-focus thing dropping down in the middle of the pic is actually a thermocouple that I added. (View is through the exit chute on the faceplate.)

#23: Post by **Milligan** » August 10th, 2022, 2:35 pm

Mbb wrote:That's a pretty broad statement. Especially as Diedrich has carbon steel drums. There's a great many roaster that have carbon steel drums. It's certainly true that stainless is easier to keep clean for food preparation surfaces, but that's hardly what the inside of a roaster is.

One difference to keep in mind is a stainless has a markedly lower thermal conductivity than carbon steel does, less than half. At room temperature of the values would be like 10 for stainless and 24.8 for carbon steel. So if someone was trying to limit the heat of conduction to the beans and maximize the convections stainless would be a choice that made sense.

But anyway it seems to be only some Chinese / Taiwan roasters that say they have cast iron drums, and that's interesting for a couple of reasons. It could be that they just lose something in the language translation, but that's been asked before and they seem sure that it's cast iron. But also, iron and steel casting is one of the huge industries of Taiwan. That is the reason that all this tool and machinery production goes on there, metal is cheap there. So it's possible that they could casting iron drums and machine them cheaply. I would think that would be inferior to a carbon steel pipe.

I did not mean to imply stainless was superior. My post was in response to the OP seeming to dismiss the BC2 because it had a stainless drum. I was replying to point out many manufacturers use stainless and it isn't necessarily a hindrance on performance.

#24: Post by **Milligan** » August 10th, 2022, 4:46 pm

I do know from other industries that cast is cheaper at scale than fabricated parts for complex designs. It takes quite a bit of scale to hit that inflection point though so I'm not sure if coffee roaster sales would get there. For example, many complicated metal parts on John Deere tractors are cast. Most tractor manufacturers are 100% fabricated because they do not have the scale Deere does.

Those pictures of interior of the partially cast drum on a small roaster are interesting. It looks like the cast fins were welded to the drum then the weld was ground down?

August 12th, 2022, 2:50 pm

Milligan wrote:I did not mean to imply stainless was superior. My post was in response to the OP seeming to dismiss the BC2 because it had a stainless drum. I was replying to point out many manufacturers use stainless and it isn't necessarily a hindrance on performance.

Bc2 is very similar to hb-M6/arc 800, which they have a carbon steel drum.

The offer for arc 800/hb-m6 came back. I am really concidering it, but the are some issues with probe latency. Artisan-scope says somewhere that they fixed the strange ROR from these machines with the "curves" option. But there is always the option to install better thermocouples or even RTDs, but this means more tweaking for me.
But it seems like a very well built machine.

September 19th, 2022, 6:04 am

So, they made me on offer I could not refuse, and I bought a Röstbiene.
I am planning to do some modding, like a better "closed" enclosure so the cold air enters from a specific area, and not from everywhere like it is now.
Which phidgets would you choose for roast logging, except from temperature. Which range of differential pressure module is optimal, or this has to do with each specific roaster?

September 20th, 2022, 8:54 am

Except from temperature? Other than BT, ET, and IT, I also monitor ambient temp and humidity and pressure differential. I believe the phidget for pressure differential is the 1136. It was out of stock when I ordered so I went with the 1137 and it seems to be working okay. I think the 1136 may give better resolution at the pressures in a coffee roaster exhaust system though. Go with the 1136 if it is available.

September 22nd, 2022, 10:31 am

And for ambient temp/hum, do I look for HUM1001?
Is there a way to log without adding buttons to artisan, the gas pressure?
I have seen once that someone had no gas pressure gauge but a digital one, and through arduino and coding he had gas logging.
And the second idea, is put a pressure differential meter like the 1136, at the gas line, where gas and air are mixed. If you increase gas, the air that is sucked in for combustion increases, so there is the logging. But this has a lot trial and error I think, as well as a custom burner that has to be made...

#29: Post by **Milligan** » September 23rd, 2022, 9:27 am

For real-time gas pressure logging the easiest way to do it is to get a digital Dywer gas gauge with data output. These are a bit pricey but are straightforward to install without modifying the gas system with DIY parts. The DPGA series is digital without data output which is what most people use (including me.) The DPG-200 series is able to transmit a signal that can be used for artisan (through the VINT HUB.) I have not used this gauge but from when I looked into it all you would need to do is buy a VINT pigtail and wire the signal line from the gauge to the VINT pigtail and then calibrate artisan from there. It is pricey at around $450 for the gauge but then you have peace-of-mind that all parts in the gas system are rated for use in a gas system.

Yes HUM 1001 is what you need for humidity. It isn't completely obvious, but it also measures ambient temperature so there is no need for an additional temp sensor for that.

September 23rd, 2022, 10:35 am

georgemvg wrote:Hello all!
I am looking to buy a roaster to start learning how to roast.
I want its adjustments to be as close as a bigger machine.
What are your thoughts?

I'm going to respond a bit differently. IMO, you don't necessarily need to find a smaller roaster that acts like a bigger one. I'd suggest you just get one that is of the same type as you intend to eventually get (e.g. fluid bed, drum, gas/electric, etc). For example, many smaller drum roasters have less thermal mass than larger ones, requiring more gas changes perhaps because of this. But, there is **so** much to learn about roasting in general that you could spend a good couple years on a smaller roaster just figuring roasting out. Yes, when you move to a larger roaster you will have to learn its differences, but isn't that going to be true no matter what?

I'd look to responses from those that have small and larger roasters to validate my thoughts. Thinking Alan since he has a Cormorant and some seriously big iron too.

EDIT: just figured out you have purchased something. Congrats! Will leave this post for posterity.