Roast Vision - a new and affordable roast level sensor for $299 - Page 10

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espressovision (original poster)
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#91: Post by espressovision (original poster) »

Hi Steffen,

No, I'm not in Boston anymore and won't be travelling to the Expo this year.

Zach

Richard Cullip

#92: Post by Richard Cullip »

I see that the Roast Vision is currently out of stock on your website. When might it be in stock again and available for purchase?

espressovision (original poster)
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#93: Post by espressovision (original poster) »

Hi Richard,

Thanks for the message. No current estimate for when we'll be back in stock, but please check our website for updates.

Apologies for the inconvenience,

Zach

M0ohamed

#94: Post by M0ohamed »

Greetings,
I have 2 roast vision devices and have access to a Lighttells CM200 scale. I did several tests to calibrate the roast vision against the CM200 and I captured videos as well, and in all of them it is always 3 numbers darker in roast vision numbers.

So when a coffee is 13 on roast vision, it shows 68 on the CM200, which is 16 on roast vision scale.
and when it showed 29 on roast vision, it showed 114 on the CM200, which is 32.
and finally when it shoed 23 on roast vision, it showed 94 on CM200, which is 25 to 26 in roast vision numbers.

I did all the tests using a super fine grind using 2 grinders, EK43, and 1zepresso Kplus.

Please advise if we need to modify the current conversion scale, or if there is a way to shift or re program the roast vision numbers, so it directly reads the 26 as 26 not 23, and so on.

Regards,
Mohamed

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Peppersass
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#95: Post by Peppersass »

I've had similar concerns about the Agtron Gourmet conversion scale. I don't have a calibrated lab reference colorimeter, but if you assume the conversion is correct, there's a significant discrepancy between the Agtron Gourmet text descriptions and the Roast Vision conversion scale text descriptions.

For example, Agtron Gourmet 82 is described on their scale as near the Very Light end of the Light range, while Agtron Gourmet 82 on the Roast Vision conversion scale is at the Medium end of the Medium Light range. Another example: I have a roast that comes out at 27 on the RoastVision. This aligns with Agtron Gourmet 99 on the conversion scale, just at the beginning of the Light range (i.e., just over the border from Medium Light.) But 99 on the Agtron Gourment scale is described as Ultra Light and Undeveloped. I can assure you that roasts I've measured at 27 on the Roast Vision are quite drinkable and not Undeveloped.

I brought this to Zach's attention and he said others had pointed out the discrepancies. After our discussion, he measured new samples with the CM100+ he used to create the conversion scale and sent them to Coffee Review for them to measure on their M-Basic. The Coffee Review M-Basic measurements agreed with Zach's CM100+ and the Roast Vision conversion scale, with only a few insignificant variations. Zach said the scale will stay the same and difference in quality descriptions will also remain. I can't fault him for that because my subjective evaluation of roast color / development is much closer to the Roast Vision descriptors than the Agtron Gourmet descriptors.

All that said, I'd like to hear Zach's response to the numeric discrepancy you found in measurements with a CM200.

PIXIllate
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#96: Post by PIXIllate »

Most of the light to ultra light readings I get from my Roast Vision (26-31) seem pretty consistent with what I would expect from the coffees. For example my Tim Wendelboe subscription coffees almost always read in the 25-28 range. Sometime I have a VERY light roast like the recent Cup Of Excellence winner I bought from Rabbit Hole Roasters that measured 31. It was very light indeed. Meanwhile the medium dark coffees I try come up in the 16-19 range which again agrees with the descriptors on the Roast Vision. Different bags of the same coffees read within one point or so of each other as I measure 3-4 samples from each bag I open.

Shrug.... I guess all of that is just another data point.

RyanP

#97: Post by RyanP » replying to PIXIllate »

Interesting, my most recent TW coffee was the Honduran from the fellow drop a couple months ago. That one measured a 31 on my roast vision. Most of my roasts out of the ikawa fall in the 30-33 range, but they don't scream to me cutting edge light.

PIXIllate
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#98: Post by PIXIllate »

My TW coffees are the Espresso roasts. The lightest commercial coffee (including lots of Filter roasts) that I've had was the Adia Battle from Panther. It came in at 33. Most filter roasts from Hatch I've had were in the 27-29 range.

RyanP

#99: Post by RyanP » replying to PIXIllate »

Ah, that's the difference. This was a filter roast.

espressovision (original poster)
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#100: Post by espressovision (original poster) »

Hi Mohamed and others!

"I did all the tests using a super fine grind using 2 grinders, EK43, and 1zepresso Kplus."

Did you use the super fine ground coffee in the CM200? I assume it is the same for the CM200, but I confirmed with Lighttells that their CM100+ requires that grind size: "follow cupping standard grinder size, 70% pass sieve mesh No.20"

Please confirm what grind size you used for the CM200 before I comment on the numerical discrepancy.

To reply to Peppersass (Hope you've been well!), I do remember discussing this and I think unfortunately some of the charts and tables with numbers that are on blogs online have miscalculations when converting from Agtron Classic to Agtron Gourmet. We did confirm that Coffee Review's M-Basic was in agreement with my CM100+ which was also in agreement with converted values from a Roast Vision. Coffee Review when we first did this testing did admit that they likely needed to be re-calibrating their M-Basic more often, so I would advise against comparing your measurements directly with theirs online, not even considering batch to batch variation from the specific roaster.

The issue with the text descriptions for the Roast Vision is that they were created before we had a conversion to Agtron Gourmet, so they were not intended to be a perfect match since initially our tool only offered the Roast Vision numbers with no way of relating them to Agtron Gourmet.

The numerical discrepancy is more important, which I'll address after your response Mohamed.