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renatoa
02/08/2023 1:20 AM
coffee drink @ RC-Roaster

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02/07/2023 7:46 PM
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Roast Color Nerdy Stuff
oldgrumpus
I'd like to determine the color of my roasts with some sort of objective (more or less) way. I guess one of the methods professionals use is technology based. Expensive meters and such are not what I'm looking for. In my own mind, there must be some reference samples with numbers assigned. The typical scale (or one of them) is Agtron. On the Agtron scale, Agtron 75 is a common reference.

Does anyone know of a sample set or single-color reference for sale? Not a chart, but real roasted beans?

Thanks!!
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
Yasu
Not answered.
I use this inexpensive colour meter.
It is highly reproducible in terms of L-values, although correction is probably necessary.
I can use it.
The unevenness of the coffee has a large error rate, so I use an espresso grinder to measure the flattened state of the coffee, which gives a stable roast degree.

https://ja.aliexp...Xg0THpSNHz
 
oldgrumpus
Thanks Yasu. It’s helpful and I might consider it if I can’t find what I’m looking for. At $112 USD, that would be considered affordable for sure.
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
Yasu
Thank you for confirming.

If you are considering buying it, I will let you know as there are a few tricks to using it.
For example, if you use a tamper to harden it, it will swing towards the white side, and with a coarse grinder it will swing towards the black side...)
(It's not for regular use, you'll need a more expensive device to really measure coffee roastiness).
 
oldgrumpus
For my purposes, I think my eyes will be a good-enough judge of color, but I need a good reference to compare with.
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
ACEMBL
If you want to make one yourself there’s a good Instructables:

https://www.instr...fee-Roast/
Edited by renatoa on 01/31/2023 1:22 AM
 
oldgrumpus
Thanks for posting this! It looks really interesting and I'm definitely considering building one myself!
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
HarryDog
Has anyone tried a TV calibration meter (or Printer meter) the cheap tri-color meters might work. Used they should be cheap but you need to connect to a computer. If anyone has seen info on this I would be interested in testing this out.
 
oldgrumpus

Quote

HarryDog wrote:

Has anyone tried a TV calibration meter (or Printer meter) the cheap tri-color meters might work. Used they should be cheap but you need to connect to a computer. If anyone has seen info on this I would be interested in testing this out.


I looked around on eBay to see if I could find such a meter. I’m wondering if it goes by another name?
Along these lines, it seems that simply using a photographic light meter would do the job if we are only measuring the reflectance of light. Is it possible that it could really be that simple? Is it something worth considering?
Clever Coffee Dripper
Grinder: Macap M4
Roaster: Completed drum roaster project photos shown here:
Photos https://goo.gl/ph...Da6K4wfqw5
Videos https://www.youtu...Bd1NrdpSUH
 
renatoa
Something like these:
https://www.creat...calibrator
 
randytsuch
A monitor calibrator is designed to sit against a screen. You paint a colored square on the screen, then place the calibrator over the square and let it measure.

You could take a picture of grounds, but then you add a camera into the mix, unless you color calibrate your camera.
 
oldgrumpus
Sounds complicated. I like the idea of the instructable posted above by ACEMBL. For us with a drum roaster, the idea of inserting the tryer into the device means real-time, while roasting, color analysis.
Edited by oldgrumpus on 01/31/2023 1:31 PM
 
HarryDog
Exactly like all those, they also use many of the same ones for printers, they just look at anything under them and evaluate the color. You don't need to take a picture and read that, just read your sample. Newer ones read the image and adjust the monitor or tv on the fly I don't remember if it gives you a number read out?

Brand names, datacolor or x-rite
I think some old freeware software might give a readout but would have to look around. I bet if you took out a free add lots of people would have these in the US for free.

I think they would work well for this if we can find software that give us a result we can use or interpret.

Very long time since I used one but creating a printing profile with one might work better?
Need to look at some software.
HarryDog attached the following images:
spyder3top.jpg spyder3bottom.jpg
 
HarryDog

Quote

randytsuch wrote:

A monitor calibrator is designed to sit against a screen. You paint a colored square on the screen, then place the calibrator over the square and let it measure.

You could take a picture of grounds, but then you add a camera into the mix, unless you color calibrate your camera.


This old one might not read in the dark (Or low light) as a monitor will supply some light.
will test the spyder and if I can find my X-rite will try that.
Now meters that can scan print outs must generate some light as they can be placed right on the printed color?
Not sure if it has any space between the meter and paper, Have one at work and can look at that on Monday.
The one we have for printers is the same model as for TV's or Monitors just different software.
 
oldgrumpus

Quote

HarryDog wrote:

Exactly like all those, they also use many of the same ones for printers, they just look at anything under them and evaluate the color. You don't need to take a picture and read that, just read your sample.


That makes it more simple, but I'll have Artisan running on a screen already while trying to evaluate the color real time which would mean another monitor somewhere if I'm understanding the color analyzer for monitors and printers correctly. Maybe if it's plugged into a tablet. Hmmm, need to think on that some.

Sure would be great if a color analyzer/meter could be in a form-factor like a hand held IR laser thermometer. Point and shoot with instant readout.
 
HarryDog
That device (LS171) that Yasu posted might be worth a look, it looks to have a readout right on the top of the device and a app.

I was hoping to get a color checker to work with the Spyder3 but no luck.
I was going to try a product called Quick color match but it looks for compatible products that are connected that you will be comparing I guess, not just lets compare?

Looks like a time wasting project unless someone writes an app to use a color meter?

Found a report of an app that uses AI to read roast level, I did not find the app but this is the article.
https://sprudge.c...89082.html
Edited by HarryDog on 02/02/2023 1:02 AM
 
renatoa
There is also other "time wasting project" that evaluate roast degree using a senor from an oximetry device, that became popular during pandemic.

https://hackaday....fee-roast/
 
HarryDog

Quote

oldgrumpus wrote:

Sure would be great if a color analyzer/meter could be in a form-factor like a hand held IR laser thermometer. Point and shoot with instant readout.


How big is the site glass on the roaster? How hot does the glass get?

I'm looking at some cheap units from Aliexpress with hand held units with a readout, 1.26 Inch diameter.
The software allows you to upload your own color cards, use ones available for roasted coffee that I see posted around as a quick template for a custom comparison, not sure how well it works through the site glass?
This is under $100CAD so $70USD?
https://www.aliex...4248%21rec
 
Yasu
Many colour-difference meters of this type have a severe distance between the sensor and the reading unit, and are designed to be placed exactly on a flat surface.
In such cases, the thickness of the glass may be an issue and the glass surface may be measured and read the wrong value.
Yasu attached the following images:
ls171173.png ls170172.png

Edited by Yasu on 02/02/2023 11:06 PM
 
oldgrumpus

Quote

HarryDog wrote:

How big is the site glass on the roaster? How hot does the glass get?

I'm looking at some cheap units from Aliexpress with hand held units with a readout, 1.26 Inch diameter.
The software allows you to upload your own color cards, use ones available for roasted coffee that I see posted around as a quick template for a custom comparison, not sure how well it works through the site glass?
This is under $100CAD so $70USD?
https://www.aliex...4248%21rec


This looks interesting. I'll check it out. Thanks.

My sight glass is 2 inches in diameter, so your find would work if size were the only thing to consider. Heat in the roaster gets over 200C. So not likely that this device would survive.

Also, check this out. I'm sure it's cheap... (said with a bit of sarcasm). But seems like a very interesting option. Maybe someone will come up with a DIY version we can afford. A laser color analyzer that looks through the site glass...


Edited by oldgrumpus on 02/02/2023 11:16 PM
 
renatoa

Quote

HarryDog wrote:

How big is the site glass on the roaster? How hot does the glass get?



What about the +200C degrees of the glass ? Shock
 
renatoa

Quote

oldgrumpus wrote:

A laser color analyzer that looks through the site glass...


I am pretty sure what you see there is an IR measurement device, and laser is used only as a pointer.
They may claim they are measuring color, but actually they are measuring an IR radiation, which is the same as the "trier in the pipe" project above.
 
HarryDog
I was concerned about the glass thickness and temp, for temp I might cut a ring out of a silicone baking mat and stick it on the bottom, you would just touch it to the glass for a moment to push the button. Might effect the white calibration tile?

or You just pull a few beans put them in a small shallow container and take the reading. I'm going to order one up and see what I can do with it. I don't have a site glass but could fill a small glass milk jug with beans and rotate it to see how the glass and rotation effect the reading compared to stationary beans without a glass barrier?

Who has those coffee bean color cards on the web?
Sweet Marias has something, will look around.
 
oldgrumpus
HarryDog, Yes, cards at Sweetmarias, others are out there too. You might want to see Sweetmaria’s video on their cards too.

Also Testrite has cards. More $ though…
 
oldgrumpus

Quote

renatoa wrote:

They may claim they are measuring color, but actually they are measuring an IR radiation, which is the same as the "trier in the pipe" project above.


That’s a very interesting possibility. Worth exploring. I know from experience that some types of glass filter out IR but maybe the borosilicate glass commonly used for site glass doesn’t. Or maybe it’s just not a factor?

The “trier in the pipe” measures IR wavelengths in 5 separate frequencies. I don’t know enough about the subject, but that must be different than measuring heat with an IR thermometer?
 
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