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Permalink Reply by Derryl Reid on August 25, 2010 at 8:23am

On my Diedrich Roaster (IR-7) I have two temp gauges, bean & drum!

I slowly bring up the temp till both gauges read the same! I do this by leaving the air go through the drum!
My drop Temp is 435 - 420F or 225-215C.

I usually go for a little higher drop temp for my darker roasts.

My Diedrich is like my old van, needs a little extra gas to get up that hill, but if you play with the peddles right you get to your destination at the time you planed!

Cheers c[_]
& happy roasting!

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Permalink Reply by Joseph Robertson on August 25, 2010 at 9:07am

Paul,
After a few years of this you will adapt and start using your eyes,nose,and ears way more than any gauge. I drop using the inspection technique. The bean surface will change and you will get to know what than means and even discover that each and every origin and season will respond differently to the process. My 1976 probat has all the upgrades and bells on it and I use them all for profiling but in the end, ahhh, drop time I use my senses more. Write and log all stages of the process and keep good records.
Joe

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Permalink Reply by Derryl Reid on August 25, 2010 at 12:39pm

I thought Paul was referring to dropping raw beans in the roaster, not finished temp?

I know for my roaster charge temp makes a huge difference!
If I start off low it is very difficult to catch up!

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Permalink Reply by Benjamin Turiano on August 25, 2010 at 3:02pm

Change your drop temperature based on how much coffee you're roasting with. The equilibrium point between the ambient temperature of the roaster and the raw coffee should be consistent every batch. We use a different point for different coffees, but I generally shoot for equalizing around 165º Fahrenheit, well below any temperatures that will be developing reactions. You'll develop a feel for what beans will absorb heat quicker or slower than others.

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Permalink Reply by Joseph Robertson on August 25, 2010 at 5:02pm

Paul? I misread your question. Sorry. Derryl and Benjamin thank you for steering me on track with this topic. Very important point. Especially Paul, if your teaching yourself how to roast commercially.
I went through roasting school in Waterbury Vt. at http://www.coffeelab.com/
Just giving you a little background on my education. By no means am I a master roaster. A roasting Padawan for sure. Mane' the man I learned from is. I trained on a Probat 5L which just happened to end up being the machine I own and use. With a full drum our drop temp is 400 degrees. As Benjamin pointed out this is reduced as the batch size is reduced. The more you roast the more of a feel you will get for what this temp should be. It will vary origin to origin and blend to blend depending. If I'm post blending the beans get to marry for 48hrs to equalize their moisture content before roasting.
Best roasting to you, I miss my old ebay Ambex.
Joe

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Permalink Reply by Derryl Reid on August 26, 2010 at 4:59am

Benjamin Turiano said:

I generally shoot for equalizing around 165º Fahrenheit, well below any temperatures that will be developing reactions.

Hi Benjamin

I find your drop temp interesting, way lower than I have ever tried. It would be lower than my bottom out temp (~185 F)
What would be your average total roast time?
This is your ambient (air) drum temp I assume not your roaster or true drum temp?

Thanks
Derryl

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Permalink Reply by zack burnett on August 26, 2010 at 5:45am

Derryl, one thing I have learned from talking to other roasters is that comparing temperatures, and to a lesser extent times, really means nothing. Unless 2 people are roasting on identical machines in the same location on the same day temperature talk really makes no sense.

One roaster will show you a full city roast and if asked what the final temperature was he may tell you 425. With my roasting style 425 would be way too low of a temperature for me to reach full city but I'm sure there is another roaster out there that would tell you 425 would be burned up Italian.

Just wanted to put that out there so if anyone, especially someone new to the game, hears some numbers that are way different from theirs they are not panicking or confused. I know when I was beginning I was confused by a lot of things, heck I still am, but I have stopped second guessing my self so much.

For the record, I shoot for an equilibrium temp of around 160 at one minute so I can hit 200 around two minutes and a full city roast on my ambex YM 15 finishes at around 440. All of my temperatures should be read as bean temperatures.

Derryl Reid said:

Benjamin Turiano said:

I generally shoot for equalizing around 165º Fahrenheit, well below any temperatures that will be developing reactions.

Hi Benjamin

I find your drop temp interesting, way lower than I have ever tried. It would be lower than my bottom out temp (~185 F)
What would be your average total roast time?
This is your ambient (air) drum temp I assume not your roaster or true drum temp?

Thanks
Derryl

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Permalink Reply by luke hudek on August 26, 2010 at 6:04am

zack burnett said:

Derryl, one thing I have learned from talking to other roasters is that comparing temperatures, and to a lesser extent times, really means nothing. Unless 2 people are roasting on identical machines in the same location on the same day temperature talk really makes no sense.
One roaster will show you a full city roast and if asked what the final temperature was he may tell you 425. With my roasting style 425 would be way too low of a temperature for me to reach full city but I'm sure there is another roaster out there that would tell you 425 would be burned up Italian. Just wanted to put that out there so if anyone, especially someone new to the game, hears some numbers that are way different from theirs they are not panicking or confused. I know when I was beginning I was confused by a lot of things, heck I still am, but I have stopped second guessing my self so much.
For the record, I shoot for an equilibrium temp of around 160 at one minute so I can hit 200 around two minutes and a full city roast on my ambex YM 15 finishes at around 440. All of my temperatures should be read as bean temperatures.

Derryl Reid said:

Benjamin Turiano said:

I generally shoot for equalizing around 165º Fahrenheit, well below any temperatures that will be developing reactions.

To an extent I agree.

I roast on a 6 lb San Fran, and we use roast log to track our roasts. When we starting using Roast Log, we had to tap for a k-type thermocouple. The readout Roast Log's software gives me is about 20 degrees F above what the machine reads out normally.

Ultimately, these readouts are there to use as an aid and to HELP keep things consistent, and calibration can vary from roaster to roaster. That being said, I try to keep my rebound temp at around 170.

For what its worth, my advice is to set aside some beans your not afraid of wasting, practice roasting, and take GOOD NOTES! We took the cheapest beans we had and spent a few days just playing around with the roaster and cupping to see how things worked on it. We had previously roasted on a much, much smaller machine, and even though we had an idea of what profile we wanted to use for our beans, it didn't translate as easily as we had thought it would. It also helped that we got to roast with the man who built the machine and train on it before purchasing it.

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Permalink Reply by Mike McGinness on August 26, 2010 at 9:37am

Agree sounded like OP was referring to Charge temp when said Drop temp. Normal accepted usage drop temp refers to the finished roast temp when beans drop from drum to cooling, charge refers to temp to "charge/load" the drum with greens....

Derryl Reid said:

I thought Paul was referring to dropping raw beans in the roaster, not finished temp?

I know for my roaster charge temp makes a huge difference!
If I start off low it is very difficult to catch up!

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