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gchamonlive

> If you get all of those variables right, you will end up with the best, well-balanced cup of coffee in your hands.

Those variables were:

- coffee/water ratio

- grind size and consistency

- water temperature

- extraction duration

But there is a fifth element that should be observed that is the water hardness. Having too much or too little magnesium and calcium disolved in the water may result in wildly different cups of coffee. Yes, that is leaning more towards the pedantic side, but if you live in a region with extremely soft water, you have to fix water hardness because it is essential to dissolving coffee compounds in it.

Water hardness graph: https://jgagneastro.files.wordpress.com/2018/12/water_coffee...

I would suggest reading How to make the best coffee at home, from James Hoffmann.

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> Water hardness graph:

Interesting graph, but I was missing some explanation. Here's the figure text, from [1]:

"Water properties for various recipes, cities and bottles. The dashed line represents a 1:1 relation, and color lines correspond to different recommended ranges.

In the figure above, you can see the range recommended by the SCA (green bar), the region recommended by the Colonna-Dashwood & Hendon (2015) Water for Coffee book (this mythical book is now pretty much impossible to find, but it is said by the ancient ones to go much deeper in the chemistry of coffee extraction than what I could ever write in this blog post), and the more constrained region recommended by the Specialty Coffee Association of Europe (SCAE), which is mainly based on avoiding regions of significant scaling (upper right) or corrosion (upper left), two aspects that are mostly important to the delicate internal parts of espresso machines."

[1]: https://coffeeadastra.com/2018/12/16/water-for-coffee-extrac...

I learned this when I tried making coffee using water from an RO unit. It was just kind of flat. I switched to filtered tap water and got better results. We get water from Lake Michigan which AFAIK has hardness about 135 ppm. I wish they had included Chicago it in the graph.

This is covered in the article right after where you quoted.

>Furthermore, the type of water you use also plays a vital role in the process of coffee extraction.

>You can learn more about the best water for coffee making, by clicking here.

https://wokelark.com/best-water-for-coffee/

From my experience, too much CaCO₃ is far worse than too little.

People sell mineral packets that you add to distilled water so you can control for this while brewing.

Both axes on the graph are "ppm CaCO₃", so why is it 2D?

The original paper where the graph comes from is not clear about it either. I think total hardness is calcium carbonate and magnesium ppm, but I am not sure.

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