Detecting defects in your cup?

#1: Post by **Tourman** » October 29th, 2015, 12:42 pm

In case you missed yesterday's streaming discussion from Mill City Roasters, you may want to view the recorded program. Last month there was an excellent discussion about cupping and this month the discussion featured Derek de la Paz, head roaster at Peace Coffee in a conversation on roasting and green coffee defects. As a new owner of a North TJ-067 I know I have found these sessions to be really helpful.

The recorded session is up on Mill City's website at https://millcityroasters.com/coffee-of-the-month/

#2: Post by **Danm** » October 30th, 2015, 2:12 pm

So Dave's profile for this same coffee was 5:27/3:51/2:21. Joe's was roughly 6:00/2:00/2:15. Allowing for personal differences in the calling of yellowing, the profiles, to me, are not all that different. Perhaps a couple of percentage points in the development stage. There was a significant difference in the charge temps. though, with Dave charging at approx. 265F, and Joe at 400F. This probably resulted in substantially higher air settings in Joe's roast as well. Since both roasts were done on the same machine, I'd be curious to see how they compared side by side in the cup.

#3: Post by **jalpert** » October 30th, 2015, 2:40 pm

Another excellent video, thanks Mill City!

#4: Post by **Boldjava** » October 30th, 2015, 4:00 pm

Danm wrote:...with Dave charging at approx. 265F, and Joe at 400F. This probably resulted in substantially higher air settings in Joe's roast as well. Since both roasts were done on the same machine, I'd be curious to see how they compared side by side in the cup.

265*. I attribute that to fiddle farting around time. Dropped around 400* if I remember.

DB

#5: Post by **Danm** » October 30th, 2015, 5:01 pm

Thanks Dave, thought that sounded pretty low!

Great vid!

#6: Post by **Boldjava** » October 30th, 2015, 7:09 pm

Boldjava wrote:265*. I attribute that to fiddle farting around time. Dropped around 400* if I remember.

DB

Yep. Went back to profile. I am a poke on getting new graph up, starting the graph, and recording the charge. BT is much more critical and I monitor that by the minute.

With a natural, I take it a little easier on heat.

I use these parameters for drops.
390-410 (using control panel PID reading)

Larger the charge, higher the charge temp
Higher the elevation, higher the charge temp
WP dropped 5* higher than naturals

Decafs, 380*

#7: Post by **tburres** » October 31st, 2015, 2:03 pm

Dave & Co. - that was a terrific video and I really appreciate the learning experience you are offering! The production team and the guests are making it very valuable and I look forward to it every month!

I had a question on airflow settings as I have been applying what you shared last month - How should I determine the appropriate range of settings for my my machine (TJ-067)? Using the lighter test is my low end where the flame just begins to be pulled inward? If that's the right starting point, for me it's at a fan setting of 12.5% -15% (testing with an empty drum during preheating). I typically increase with 2.5% steps on the dial, and at 20 or 22.5% I am pulling the flame so hard it goes out. I have moved most of my profiles to start at 15% and I adjust to 17.5% as I approach the end of the drying phase. I am generally finishing with airflow at 22.5 or 25%. Does this sound like a reasonable range?

I also wanted clarify something you said during the discussion about baking - you mentioned that you watch for your RoR to plateau as a sign that you may be baking. I think a RoR that is 0, so no rise at all, for an extended period is what is meant by baking. Any RoR higher than 0 means your BT is still rising and that's not what is generally referred to in the context of baking. Am I understanding that correctly or would you say that holding a steady RoR of say 6F/Min for 2 minutes would cause baked flavors?

Thanks again to you guys for all you're doing - I hope I will have an opportunity to visit the shop some day!

#8: Post by **Boldjava** » October 31st, 2015, 3:32 pm

tburres wrote:Dave & Co. - that was a terrific video and I really appreciate the learning experience you are offering! The production team and the guests are making it very valuable and I look forward to it every month!

It is our pleasure. We are enjoying lining up and producing these. Glad to know they are of benefit.

I had a question on airflow settings as I have been applying what you shared last month - How should I determine the appropriate range of settings for my my machine (TJ-067)? ... Does this sound like a reasonable range?

Your approach and logic are correct except for one thing. I would test and evaluate when the roast is in the drum, not when the drum is empty.

I also wanted clarify something you said during the discussion about baking...

It is my understanding that flat or plateaued rates, as well as ascending ROR during the drying and development phases, flattens the acidity and leads to baking. I am after a consistently descending ROR after the line reaches its zenith at the left end of the curve.

#9: Post by **tburres** » November 2nd, 2015, 5:54 pm

Thank you Dave!

#10: Post by **dcupstateNY** » November 3rd, 2015, 2:50 pm

Dave & Co. - that was a terrific video and I really appreciate the learning experience you are offering! The production team and the guests are making it very valuable and I look forward to it every month!

+1 Truly enjoy these videos ... you guys rock!