Hi,
I am running into some problems with my roast profile on my Diedrich IR-12. Below are two15# profile roasts that I have completed and am getting a coffee taste with a flat flavor. Any help from you all would be greatly appreciated.


15# Costa

Drop 415 f – gas @ 80%

After 1 min. drop gas to 50%

Bottom out – 167 f

240 f @ 3:75 – 4:00min

280f – 50/50 air

305f @ 6:00min

370f @ 10:30 – Full air

1st crack 382f @ 11:00

Finish temperature 432f – start of second crack (15:20 min)

Roast development 4:20 min.

Coffee is flat w/o flavor


15# Guat

Drop 415f – gas @ 80%

After 1 min drop gas to 50%

Bottom out – 163f

240f @ 4:00 min

280f @ 5.5 – 6:00 min

280f - 50/50 air

305f @ 7:00 min.

370f @ 10:05 min – Full air

1st crack 381f @ 11:00min

Finish temperature 431f – start of second crack (15:42 min)

Roast development 4.42 min

Coffee is flat w/o flavor


15# El Sal

Drop 415f – gas @ 80%

After 1 min drop gas to 50%

Bottom out – 163f

240f @ 4:00 – 4:30 min

280f @ 5.5 min

280f - 50/50 air

305f @ 6:30 - 7:00 min.

370f @ 10:05 min – Full air

1st crack 376f @ 11:00min

Finish temperature 432f – start of second crack – 15:00 min

Roast development 4:00 min.

Coffee is flat w/o flavor

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Hi,

I am roasting 15#'s of Costa, Guat and El Sal.

I am located in Calgary, AB Canada with an elevation of 3500 feet above sea level.

What should my profile look like to get the high notes?

Thanks



D. Smith said:

I roast on a Deidrich. How much coffee are you roasting per batch? Depending on what you are trying to achieve, you need to find your sweet spot as far as optimal batch size. If you are looking for high notes then your profile is incorrect. I would use your profile if my goal was to mute acidity and flavour.

When I read your profiles above, each have a roast developement time of around 4 to 4 1/2 min. according to your log. Generally I would think thats inline, but in a case where it seems your losing some acidity and high notes, I would say cut that down to about 3 min. which means you would be staying on the throttle longer rather than cutting back on the heat and dragging the RD time longer. That's one area I would target and see the difference it makes in the coffee.

Just curious, what was the weather like when you performed these roasts that were "flat". I roast right near the beach and I have to account for humity when I roast and sometimes adjust accordingly which can sometimes be challenging because as you correctly stated earlier you need to think at least 2 minutes ahead.

The temperature was -2 degrees Celsius = 28 degrees Fahrenheit. We have very low humidity.

Our weather and altitude are very close to what you would find in Denver Colorado.

I was born and raised in Calgary. It is very cold, but its a dry cold. Lol. Humidity plays a large role in roasting coffee. Especially if your beans are stored in a dry environment. I am assuming you don't have a moisture meter? It's hard to help someone roast when there are so many variables involved. The first thing you should know is that the Deidrich roaster uses different burners than other roasters. It also uses heat exchangers in the ir12. The other thing is that it has a different airflow system. That being said, you need to make adjustments for this in your roast style. The other thing is don't confuse bean temperature with atmospheric temperature. Your batch size might be a little light. Your charge temp is too high and I am confused by the drop in temperature at the start of your roast. It seems way too low. What is the temperature of your roasting facility?

Is your bean storage room cold? That might account for some of the issues with using such high gas at the beginning.  I don't let turning point / bottom temp get down below 172-175. At ~165 you are using a lot of energy at the beginning of the roast just to get things moving and in my experience, the roasts just aren't that good.

N. Hewitt said:

The temperature was -2 degrees Celsius = 28 degrees Fahrenheit. We have very low humidity.

Our weather and altitude are very close to what you would find in Denver Colorado.

What charge temperature would you suggest? As well, what bottom temperature s ideal? What batch size is ideal for an IR-12.

Thanks

D. Smith said:

I was born and raised in Calgary. It is very cold, but its a dry cold. Lol. Humidity plays a large role in roasting coffee. Especially if your beans are stored in a dry environment. I am assuming you don't have a moisture meter? It's hard to help someone roast when there are so many variables involved. The first thing you should know is that the Deidrich roaster uses different burners than other roasters. It also uses heat exchangers in the ir12. The other thing is that it has a different airflow system. That being said, you need to make adjustments for this in your roast style. The other thing is don't confuse bean temperature with atmospheric temperature. Your batch size might be a little light. Your charge temp is too high and I am confused by the drop in temperature at the start of your roast. It seems way too low. What is the temperature of your roasting facility?

The other thing that was mentioned earlier in the thread was batch size. For an IR-12 optimal batch size is probably closer 20#. Using this larger batch size will obviously change all the numbers, first being early on the turning point. Using the larger batch size will probably give you a turning point closer to 170-175 which is what one of the earlier posts suggested.

That might be the first place to start. All the other numbers will adjust along with it, although I still feel your charge temp. should be a little higher, just my 2 cents.

 

What are you using for a roast program? The section of BT-RoR you showed a bit of drag into the ramp after drying where it dipped to 15/min. I'd try to smooth out that dip a bit. Do you have your RoR readings coming into first to dump? There also tends to be a natural dip as 1st gets rolling. The trick I find is not coming into first too fast while avoiding too much of a slow down for the min or so where the majority of the beans are cracking. Keeping the finish time closer to 3-3.5 for adequate development and maintaining the acidity your looking for.  

Hi David,

You have brought up an interesting point. We roast in an old warehouse and the temperature can fluctuate. However, there is a room where I can move my beans and better control the temperature. Thanks for the suggestion.



David Myers said:

Is your bean storage room cold? That might account for some of the issues with using such high gas at the beginning.  I don't let turning point / bottom temp get down below 172-175. At ~165 you are using a lot of energy at the beginning of the roast just to get things moving and in my experience, the roasts just aren't that good.

N. Hewitt said:

The temperature was -2 degrees Celsius = 28 degrees Fahrenheit. We have very low humidity.

Our weather and altitude are very close to what you would find in Denver Colorado.

Aside from the great information your getting on the roast profiles, are you sure you're roasting fresh beans and not past crop? If the suggestions aren't working, maybe try a different roaster.

We strictly roast SHB from two reputable suppliers. Getting used to the new roaster is what has been our main issue. We've been happy with our profiles on our previous machines, but the Diedrich is an entirely different beast, and the learning curve has been steep. We are almost there though.

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