In this post, I discuss the composition of water that we use to brew coffee. If you are new to these discussions, I strongly recommend that you first read this previous post about brew water.
Barista Hustle recently released a very clever Excel calculator to determine the amount of mineral concentrates needed to craft brew water recipes starting from soft tap water instead of distilled water.
I thought this was a great idea, and decided to make a similar tool for those like me who prefer to use a single concentrate. While I was at it, I made it in a way that allows you to use more minerals on top of epsom salt and baking soda, which allows to control the concentration of magnesium, calcium, sodium, sulfate and bicarbonate ions individually, instead of just hardness and total alkalinity.
We are only beginning to understand the effects of magnesium, calcium and sodium ions on how fast different chemical compounds extract; this is discussed a little in the Barista Hustle water course, but so far I have not seen much more information about this elsewhere. However, I have never seen much discussion on the effects of sulfate ions on the resulting coffee taste or composition. This new water crafting tool could allow us to experiment with it while keeping everything else fixed.
The uses of this tool go even further; if you have reverse osmosis water with non-zero mineral composition, you can adapt your concentrate to still get the proper brew water composition. You could even use it to craft custom brew water starting from soft water bottles.
One thing this tool won’t allow you to do is create brew water that is lower than your tap, reverse osmosis, or water bottles in either total alkalinity, hardness, or individual ionic concentrations. This is because doing so by adding minerals is just not possible (maybe that would be possible with reactive compounds, but let’s not go there).
The tool I built is a Google Sheet; if you are new to Google Sheets, keep in mind that you won’t be able to modify it before you create your own copy, with File/Make a Copy. Asking me for edit permissions won’t work; doing so would modify the sheet for every other user. You can find the tool here.
Make sure to read the header instructions of the sheet. There are a few different versions of the calculator for those who don’t have access to all minerals.
I thought this was also a good moment to release publicly two of my previous Patreon-only videos related to brew water. In the first one, I filmed myself crafting a single batch of Rao/Perger brew water concentrate; you can find more explanations about the required material here;
In this second video, I use the concentrate to prepare a 4L container of brew water, starting with distilled water; you can find some more information about it here;
I’m hoping this will help you brew better coffee, hopefully with a little less hassle for those of you lucky enough to live in a soft water area !