asicign wrote:I've been home-roasting for a bit under a year now. I'm still using a heat gun, but looking to upgrade. I have a science background, so I've tried to apply the 'scientific method' to my roasts. I've found that there are too many variables even with my primitive equipment to determine what I've done to get to approach the perfect cup of coffee. Nevertheless, I personally appreciate hearing about the physical changes and chemical reactions going on, even if they don't influence my decision-making for a roast.

Any and everything about coffee is open to discussion. I am not trying to stifle discussion. I do think that bringing up purported chemical and physical changes that are not easily observable, are a distraction in a thread about "hands-on" roasting. These topics deserve their own threads, in my view.

I do not believe that we fully understand these processes and that they do not necessarily correlate easily with the observable time and temperature phenomena a home roaster uses to control his roasts. If someone asks a question like, "my coffee is flat tasting with my XXX roaster, and my total roast time is 27 minutes," the most useful commentary is not about chemical reactions, rather would have to do with the time and temperature profile of the roast and how that might be changed.

From what I have observed, many people do not agree that YYY chemical process occurs at ZZZ temperature after QQQ minutes. People do tend to agree, however, that certain obvious characteristics of a roast profile will have a certain observable result, such as an excessively long roast resulting in flat or baked tasting coffee.

Anyway, that is how I see it.

ken

Gismar wrote:I have been roasting on a diedrich-hr 1 roaster for approx. one year, and I am looking forward to hearing how you will profile on your new roaster. My roaster is an electric one, and will not be comparable with your results - but the user-manual that comes with the roaster says the same things you have said. I have experienced that roasting on a Diedrich often comes in conflict with methods use by others. What I struggled with for a while, was following the Diedrich's advice on having 1st crack in 11-13 minutes, and at the same time have a finish of 4-5 minutes. I often cupped coffee with to much roast/burned flavour - like it was overdried. If I finish a roast with 4-5 minutes after 1st, I must have a 1st crack in 8-10 minutes.(snipped)

My first roast that was successful who followed the Diedrich recommendation on 1st crack, had a finish in 2,5 minutes. This roast did not have very acidic taste, which one should expect. When I was roasting for espresso I got real problems with the 11-13 minutes, and often got burned flavour in the cup.

I have been looking at this roaster for a time, and maybe some day I will buy one myself. Can I ask approx. what the cost is for the Diedrich ir-1?

I appreciate the information you have provided. Stephen told me that one of the reasons they stopped producing the HR-1 was out of liability concerns when it comes to dealing with the public. They see their niche as dealing with coffee professionals. He wasn't saying the HR-1 is dangerous, just that you never know what a given person might do and they didn't want to take responsibility for that any longer.

The IR-1 cost $6500 plus crating and shipping when I bought it; that is a US price and I have no idea what it would cost delivered in Europe. I avoided the crating and shipping charge (would have been $750 to my location) by picking it up myself. The sense I got was that this is not really the way they want to sell these things (e.g. loading it in the back of someone's car or truck) so I can't say they will allow this option in the future. I also think that the impression I got from Stephen (he did not say this; just my impression) was a bit of surprise that a home roaster would buy one. I hope they will continue to sell them to interested home roasters but if liability concerns become more serious, they might be less enthusiastic about this going forward.

ken

Ken Fox wrote: I also think that the impression I got from Stephen (he did not say this; just my impression) was a bit of surprise that a home roaster would buy one. I hope they will continue to sell them to interested home roasters but if liability concerns become more serious, they might be less enthusiastic about this going forward.

ken

I fear this also. I've yet to find any legal way to avoid liability and need for liability insurance as well as the reduction by having UL certification with a non-business sale of a roaster.
Marshall, got any ideas???

Congratulations Ken on your IR-1!

I am still getting used to how this roaster works best coming from a Hottop and I am finding that Diedrich's suggestions give me far better roasts then trying to do it from my past experiences. I have 50lbs experience but feel I need another 50lbs at least before I will be more comfortable.

Did you go with Natural Gas? My house supply pressure is maxed at 13.5 mBars, under the recommended max pressure of 17 mBars. In the spring I will talk to the gas company about increasing my pressure at the main or talk to Diedrich about changing over to propane. I am curious to hear your max gas pressure and if you are using the max in your roasts.

Hi Rob,

I was wondering when you'd come up for air

My roaster is being installed as I type this. It will use natural gas but I also bought a jet for propane should I ever need to change fuel types.

After getting the gas company to come out last week, I now have 8" of water column pressure which is what Diedrich was using to test my roaster in the factory last week. I don't know how to correlate this with mBars off the top of my head.

There are simpler things you can do to get good heat production other than changing pressure of the gas; you can increase the hole size in the jet. You might want to call Naomi at Diedrich about that.

Gotta run and good luck, yourself!

ken

FYI, I think 8" of water is about 20 mbar.

Ken,

Sorry, should have kept it in inches of WC. I max out at 5.2-5.5 inches WC on the roasters gauge so I am really .8-.5 under what Diedrich suggest for max pressure at the gauge. Let me please know what max pressure you have when all is set up. Tech has been very helpful from Diedrich since the manual still was not complete when I received my IR-1 (may still no be) and I will be getting in touch with them very soon to see if I can get some more heat, thank you for that suggestion.

Rob,

The manual is now completed; they sent me a pdf file copy this morning. If you call the front desk they should be able to send you one, or PM me. Please, no one else ask me for it, since I think they regard this as proprietary information.

I have 7 inches of water column at the gauge, but I would have had probably around 5.5 if I hadn't called the gas company and asked them to increase it last week. It took the technician less than 5 minutes to do this outside the house and there isn't any reason I can think of why your local gas company can't do this for you also. It is winter here, also, and I don't think that has anything to do with their ability to turn the regulator screw where the gas enters your house (through the gas meter).

I have now done 3 "seasoning roasts" with a pound of coffee each. At this point I am wondering whether I'll be able to roast less than 2 lbs with the gas jet I have in place. I hit first crack at about 5.5 minutes the first time, at 7 minutes the 2nd time, and only a little later the 3rd time. On the third roast I had the gas turned down to 3 at the gauge, and the lowest I can go is around 2.25". I guess I could always increase the airflow but I'm not sure that is a good idea.

I'm burning through some old crap coffee I had lying around, but I need to order some practice coffee pronto.

ken

Addendum: It is now fully installed; before the exhaust install was temporary. Due to my altitude and concerns about the gas pressure at my house, we'd decided to go with a slightly larger gas jet size on the burner. This appears to be giving too much heat production, in that I don't think I'll be able to roast 1 lb batches at all (roast goes too fast). I did just do a 2lb "seasoning" roast and was able to get in the ballpark of the times Stephen Diedrich prescribes; I used only 3" of water column pressure which turned out to be a little bit too low. Most probably I'm going to have to go back to the regular jet size if I want to have the option to roast smaller batches.

Exhaust hose is the Armadillo hose from Federal Hose recommended by Diedrich for this roaster. Smoke hood is "left over" from earlier sample roaster. It may come in handy for the smoke that results from dumping the roasted beans into the cooling tray. Stainless roaster table was a floor sample from a restaurant supply house; they cut the legs down a few inches to provide a comfortable height for working. It cost around $150, all told.

Ken Fox wrote:Rob,

The manual is now completed; they sent me a pdf file copy this morning. If you call the front desk they should be able to send you one, or PM me. Please, no one else ask me for it, since I think they regard this as proprietary information.

I have 7 inches of water column at the gauge, but I would have had probably around 5.5 if I hadn't called the gas company and asked them to increase it last week. It took the technician less than 5 minutes to do this outside the house and there isn't any reason I can think of why your local gas company can't do this for you also. It is winter here, also, and I don't think that has anything to do with their ability to turn the regulator screw where the gas enters your house (through the gas meter).

I have now done 3 "seasoning roasts" with a pound of coffee each. At this point I am wondering whether I'll be able to roast less than 2 lbs with the gas jet I have in place. I hit first crack at about 5.5 minutes the first time, at 7 minutes the 2nd time, and only a little later the 3rd time. On the third roast I had the gas turned down to 3 at the gauge, and the lowest I can go is around 2.25". I guess I could always increase the airflow but I'm not sure that is a good idea.

I'm burning through some old crap coffee I had lying around, but I need to order some practice coffee pronto.

ken

Addendum: It is now fully installed; before the exhaust install was temporary. Due to my altitude and concerns about the gas pressure at my house, we'd decided to go with a slightly larger gas jet size on the burner. This appears to be giving too much heat production, in that I don't think I'll be able to roast 1 lb batches at all (roast goes too fast). I did just do a 2lb "seasoning" roast and was able to get in the ballpark of the times Stephen Diedrich prescribes; I used only 3" of water column pressure which turned out to be a little bit too low. Most probably I'm going to have to go back to the regular jet size if I want to have the option to roast smaller batches.

Ken,

So we are have the opposite problems. I have an email in at tech to see if they think I should increase jet size or increase pressure but now I know doing both will be a mistake. I have full control over 1lb of beans but have to run full 5.2 WC the entire roast to get a kg done in 18min.

I did not purchase the Federal Hose since I did not need 25' of it, I have a very similar setup as yours in the garage. Curious if you got the entire 25' of hose or did they sell you a shorter length?

Rob

Edit: I did 3lbs of beans per batch for the drum seasoning, but I had about of 30lbs of 2-3 year old green beans waiting for the IR-1 to come.