yakster wrote:I pulled some samples at first crack but got some high readings ~118 where I'd expect something around 95 for the Gourmet Agtron scale and based on the Sweet Marias roast color cards I picked up...

I've been thinking about this and the discrepancy seems to be that I'm expecting 95 Agtron at first crack for ground coffee but that's the typical value of coffee at first crack for whole bean. The ground coffee values are going to be higher. I wish I had gone ahead and measured all four roasts first crack and roasted coffee samples now.

Yesterday I roasted 5-1lb batches of Ethiopian Guji Derikocha G1 natural beans... the goal was to try various lengths of development time post 1st crack to find the bean's sweet spot. It's very interesting to verify the differences in color, and then sample them to see how the flavor was affected. According to my color meter's calibration, the numbers are as follows;

Agtron 100 = 1 minute 20 seconds, dropped during 1st crack - 17%
Agtron 94 = 1 minute 30 seconds, dropped during 1st crack - 19%
Agtron 89 = 1 minute 45 seconds, dropped during 1st crack - 21%
Agtron 79 = 2 minutes from 1st crack - 22%
Agtron 75 = 3 minutes from 1st crack - 26%

can we try add an anchor point, like drop temp?

Even though my case may read slightly differently from the original design of this thread, I think it's a good idea. I mocked up something like that for the roast-level comparisons in the photo above. Here's how it plots on the scale with time and drop temps highlighted.

Been learning about resin printing and liking the results... now to learn about finishing techniques for a matte, satin, or glossy spray-on finish. If anyone is interested in a case with this format, you can PM me and we'll work out the details.

that looks awesome!, is that a tamper size so the grounds can be put in a filter basket?

Yes, it was designed for use with a filter basket... mine is a 54mm double shot basket, but it was made universal and should work for other basket sizes too. Another feature is that the sample can be tested using the unit itself, if someone doesn't want to use a filter basket for some reason. A minimum of about 6-7 grams would be required depending on the grind size. I'll be making a user video of it in the coming days...

Brewzologist wrote:I'm going to create a draft scale for the DIY meter similar to what EspressoVision did for their meter.

Any progress on your scale?