popeye wrote:I've automated the airflow on my diedrich and I use it as my control process to set ET (via PID). Now my gas pressure controls the bean temps indirectly but proportionally - raise the gas pressure, PID increases airflow to maintain ET, and the increased airflow causes a more rapid rise in BT.

Interesting set up. I assume that the ET response to air flow is even more rapid than to gas burner?

kwantfm wrote: The other part of the problem is that I haven't really settled on what I want, nor what is acceptable from an emissions/odour perspective for the neighbourhood. I expect that I've glimpsed over the edge of the precipice and may well pull back significantly. Nevertheless the exercise has been very good in helping to calibrate pricing expectations for different calibres/capacities of roaster.

From my experience, unless you have an afterburner, this is down to batch size / roast degree. With batches around 650 grams, taken to city/city+, my neighbors weren't surprised when I told them I was roasting coffee, as they'd noticed a new smell, but they said it was "very faint." The few times I've accidentally gone into second crack, not only did my whole house smell, but my wife mentioned she could smell the difference while doing yardwork outside. But I live in a neighborhood in Portland where every few blocks you'll notice either coffee roasting, beer being brewed, or even the occasional medical marijuana operation.

Since I roast in my basement, the easiest setup was to vent at street level, but I'm pretty sure if I extended my ventilation to the roof, emissions would be less noticeable. Hasn't been an issue though, since my neighbors all like the smell..and it probably doesn't hurt that I give them free coffee!

kwantfm wrote:Hi there,

I was rather hoping that you would chime in. I'm particularly interested in your thoughts on roast profile movement from small to large roasters.

Diedrich pricing in Australia is extremely high. IR 2.5 ~27.5k and IR-5 ~38k. The differential between US pricing and Australian pricing is extremely large. Giesen, Joper and Probat all much smaller differential.

I would assume you would order the roaster from Diedrich to your specs and then crating and shipping. Where does the extra money go?

Moving from the HotTop B to a 1kg commercial roaster took some getting used to. Thankfully Ken Fox got his IR-1 about the same time as me and with his help I got out of my electric lag ways and got things smoothed out using gas.

I would say a huge difference from small to big is the temp stability of a 125lb+ commercial roaster. I see people post preheat times for their machines at 15min yet most will allow their espresso machines to heat for 45min before pulling the first shot. When the mass of a commercial machine gets to its thermal stability repeatable roasts are much easier. I had a routine with the Ht for preheating before the first roast and for the cooling and restart up for consecutive roasts which worked but was time consuming at 2 roasts per hour, now I do 3kg an hour taking it easy.

I find that tweaking profiles for a particular bean is easy to do on my Diedrich. Is it the machine or did I just learn more by roasting more? When I switched to the Diedrich I had 3 years of practice on the HT, I learned how to get great results from my roasts but at that time was not working on fine tuning a roast. Now with many more roast under my belt I spend a lot of time making little teaks to a profile to see the out come. This has lead me to buy greens at a minimum of 20lbs but more and more I am buying 50-100lb bags so the 20-30 different bean varieties I used to have with a small roaster has switched to 3-5 different beans for the year.

I would assume you would order the roaster from Diedrich to your specs and then crating and shipping. Where does the extra money go?

Moving from the HotTop B to a 1kg commercial roaster took some getting used to. Thankfully Ken Fox got his IR-1 about the same time as me and with his help I got out of my electric lag ways and got things smoothed out using gas.

I would say a huge difference from small to big is the temp stability of a 125lb+ commercial roaster. I see people post preheat times for their machines at 15min yet most will allow their espresso machines to heat for 45min before pulling the first shot. When the mass of a commercial machine gets to its thermal stability repeatable roasts are much easier. I had a routine with the Ht for preheating before the first roast and for the cooling and restart up of consecutive roasts which worked but was time consuming at 2 roasts per hour, now I do 3kg an hour taking it easy.

I find that tweaking profiles for a particular bean is easy to do on my Diedrich. Is it the machine or did I just learn more by roasting more? When I switched to the Diedrich I had 3 years of practice on the HT I learned how to get great results from my roasts but at that time was not working on fine tuning a roast. Now with many more roast under my belt I spend a lot of time making little teaks to a profile to see the out come. This has lead me to buy greens at a minimum of 20lbs but more and more I am buying 50-100lb bags so the 20-30 different bean varieties I used to have with a small roaster has switched to 3-5 different beans for the year.

Edit: gas supply and exhaust are something that need a lot of consideration when choosing the capacity of a roaster. I do not have the pressure in my NG line at my home to run a 5kg Diedrich. My IR-1 cyclone exhaust fan has a maximum of a 25' run and every 45 is the same as 5' of straight pipe. Roasting companies are not in the gas business or the exhaust business and they are the blood and air for your beast so getting that set up correct is on you.

germantown rob wrote:I would assume you would order the roaster from Diedrich to your specs and then crating and shipping. Where does the extra money go?

That's the cost from the Diedrich rep here. They tell me that there are significant alterations that need to be made for gas compliance. As previously stated I think that the premium charged for Diedrich here in Australia is much larger than that for premium Europeans. It's sad but it rules out Diedrich for me here.

I'd like to know how they are dealing with gas compliance. Perhaps those owners are on HB? If so please do chime in or PM.

I believe that compliance requirements are different in the various states.

Recently (last week!) a 4-kg BellaTaiwan Evo with perforated drum came here to Los Angeles. It was not that difficult to self import.

Now this is another variable in air flow, to scale from solid 500g to perforated 4kg drums. From what I heard, not too complicated.