Coffee Data Science

Double Coffee Roasting to Save a Mistake

A short story of correcting a mistake

Robert McKeon Aloe
2 min readSep 2, 2022

In the past 8 years, I have roasted around 500 roasts on my Hottop. I have only messed up a few by dropping the beans too soon or too late. One time, my son hit the button, and the beans hadn’t gone through the first crack. So I put them right back in, and the roast turned out okay.

This situation happened again, but it was my fault. I had been working on a process for modifying green beans using Koji rice. I had my beans prepared, but it was hard to determine the first crack. I dropped the roast too soon.

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The beans were clearly under roasted, and I knew I wouldn’t have a good experience drinking or extracting the coffee. I measured density to be sure, and the density was 0.63 g/ml. The maximum density in roasting I have seen is around 0.53 g/ml for a light roast.

So I took a risk knowing I would either have a severely under-roasted coffee, a over-roasted, or maybe something better.

Second Roast

I threw them back in, and I hoped for the best. I paid close attention, and I let them run a little longer because of the Koji rice processing.

The new density was 0.44 g/ml, and the color looked a lot better.

The beans turned out to be fantastic. It was a relief to know that I could correct such a mistake, but that’s not always a given. You never know if you don’t try.

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Further readings of mine:

My Future Book

My Links

Collection of Espresso Articles

A Collection of Work and School Stories

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Robert McKeon Aloe

I’m in love with my Wife, my Kids, Espresso, Data Science, tomatoes, cooking, engineering, talking, family, Paris, and Italy, not necessarily in that order.