What to look for in a roast profile - Page 2

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
EddyQ

Postby EddyQ » Feb 20, 2019, 8:16 pm

Birdcollin wrote:The varying DT% is an exercise that I'm currently learning to execute. How do you stretch your development without stretching the middle phase? If I want to hit the same end temp but stretch the time to get there, I have to enter 1C a bit slower which also stretches the Maillard phase as well. Any suggestions?


If you are also trying to preserve that ideal Rao linearly declining RoR, you would have an impossible task. But if you allow it to be less linear, still declining the whole roast, you can achieve many different DT% with the same drop temp.

For instance, for a drum roaster, if you charge hotter and hit the heat hard right away. Then lower heat at EOY (end of yellow). If the remaining curve matched the baseline, then the DT% would be longer. The roast time would also be shorter. Malliard likely would be only slightly longer.

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drgary
Team HB

Postby drgary » Feb 21, 2019, 1:21 am

Ryan,

What books have you read?

You've got your roaster so well modded and controlled that now I think you can go for the long learning curve of roasting to emphasize the most desireable flavor characteristics of high quality greens. You may want to participate in some Roast and Learn Together threads where people compare profiles for the same coffee.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

devlin2427

Postby devlin2427 » Feb 21, 2019, 9:22 am

eltakeiteasy wrote:Hi Devlin,

I hope all is well. Thanks for taking the time to give some feedback. Would you mind expanding on these items?

1. Your BT reading is about 20C above what it should be. That means you picking up too much air with it. I would pull it back a few millimeters.

I am not sure what you mean by my BT being 68F (20C) above where it should be? When you say it's picking too much air and you would pull it back a few millimeters what are you referring to?

2. I would decrease the batch weight to the point where I can comfortably get a 4 minute dry and 4 minute maillard. The development is up to you.

I can change my curve and hit 4-minute mallard, but I wanted to try to hit the baseline of 45/35/20% as close as possible before making too many changes. I have been reading Robert Hoos book and I was mainly focusing on page 40 as I have been developing my different phases %. One thing that I was completely intrigued with was the part on page 38 about Time Relative to Baseline with the Flavor Profile. Really cool stuff! I was going to post the excerpts but I figured people could buy the book if they want the info, as I don't want to take money away from Robert.

3. The bean holder/chamber glass should have a reversed milk bottle shape. Or even like an old gas lamp.


It does, but many fluid-bed roasters do not. What the rationalizing behind this? The insert sits inside the stock glass chamber like so:
[/quote]

In an ideal setup the BT should be on the return bean slope that doesn't come in contact with the hot air that moves/roasts the beans. I'll post below a picture of my setup where, I hope, you can see the placement of the probes. Also the shape of the roasting chamber.

Image

Most roasting books are based on drum roasting theory and don't necessarily translate well to fluid bed.

I would be a little bit more concerned about the actual temperature of the hot air hitting the beans. Temperatures over 500F can really damage the bean.

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drgary
Team HB

Postby drgary » Feb 21, 2019, 11:14 am

If you haven't read it, Modulating the Flavor Profile of Coffee by Rob Hoos would give you a start on adjusting flavor at different stages of the roast. I don't believe that book is drum-specific. I attended a class of his where he demonstrated on a fluid bed roaster.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

eltakeiteasy

Postby eltakeiteasy » replying to drgary » Feb 21, 2019, 1:36 pm

Hi Gary, thanks for taking the time to post! (I mentioned this in post 10, but there was a lot of text there...) I have been reading Robert Hoos book and I was mainly focusing on page 40 as I have been developing my different phases %. One thing that I was completely intrigued with was the part on page 38 about Time Relative to Baseline with the Flavor Profile. Really cool stuff! I was going to post the excerpts but I figured people could buy the book if they want the info, as I don't want to take money away from Robert.

eltakeiteasy

Postby eltakeiteasy » Feb 21, 2019, 1:41 pm

drgary wrote:Ryan,

What books have you read?

You've got your roaster so well modded and controlled that now I think you can go for the long learning curve of roasting to emphasize the most desireable flavor characteristics of high quality greens. You may want to participate in some Roast and Learn Together threads where people compare profiles for the same coffee.


So far I have read

1. Modulating the Flavor Profile of Coffee by Rob Hoos
2. The Coffee Roaster's Companion by Scott Rao
3. Coffee Flavor Chemistry by Ivon Flament
4. Home Coffee Roasting: Romance and Revival by Kenneth Davids

Most of these were a quick read as I was mainly trying to get a baseline understanding of roasting for some programming. I probably need to go back and re-read them with your thoughts in mind.

If there is anyone that has been roasting on a fluid-bed for some time there's a great opportunity for you to write a fluid-bed specific roasting companion IMO.

eltakeiteasy

Postby eltakeiteasy » Feb 21, 2019, 1:48 pm

devlin2427 wrote:It does, but many fluid-bed roasters do not. What the rationalizing behind this? The insert sits inside the stock glass chamber like so:


devlin2427 wrote:In an ideal setup the BT should be on the return bean slope that doesn't come in contact with the hot air that moves/roasts the beans. I'll post below a picture of my setup where, I hope, you can see the placement of the probes. Also the shape of the roasting chamber.


That's about where I have mine right now. Not sure if you can see it or not here:

Image

devlin2427 wrote:Most roasting books are based on drum roasting theory and don't necessarily translate well to fluid bed.


I agree. I think the thoughts around time and temp are the only real area that I have been able to translate with a direct correlation.

devlin2427 wrote:I would be a little bit more concerned about the actual temperature of the hot air hitting the beans. Temperatures over 500F can really damage the bean.


I normally stop the roast before even reaching 450F I think 425F is a good sweet spot on my roaster.

My basic strategy at first was to do the following:

1. Hold the starting temperature until the beans hit 300F. Adjust the starting temperature to get the right amount of drying (higher starting temperatures for faster, less complete drying)
2. Start the ramp when the beans hit 300, finishing just before the first crack when they hit 385 to 390.
3. The final temperature is based on the depth of roast and how 'tough' the beans are. SO I decided to set this function so the roast finishes to whatever level you desired at least 3 minutes for brewing to at most 5 minutes for espresso.

Again this was a very basic profile that I realized from reading a few roasting books. I have now gone and started to control the roast via software at each phase with control over each % of the total roast time.

devlin2427

Postby devlin2427 » Feb 22, 2019, 4:10 am

If you are reaching 450F BT with the probe in that position, I'm 99% certain you're blasting the beans with 500F+ hot air.

In my setup I've inserted a 10cm metal tube between the exit of the resistance and the sieve where the beans sit. That way I can keep temperatures below 500F.

I don't usually go beyond 15% development because I'm interested in as light a roast I can get. I couldn't get any decent light roasts when the resistance was too close to the beans.

eltakeiteasy

Postby eltakeiteasy » replying to devlin2427 » Feb 24, 2019, 3:25 am

The roaster I am using is not capable of going to or over 500F. Max is 450F

devlin2427

Postby devlin2427 » Feb 24, 2019, 5:58 am

How do you know that?

If you're getting a 450F reading with a probe between beans at around 20cm from the exit of the hot air nozzle, I can guarantee you're hot air is over 500F.

As a side note, home hot air roasters seem to be rarely concerned with the hot air temperature.