October 21, 2022

Water for brewing Coffee

Here is an often overlooked topic. But consider: water is at least 98 percent of your cup of coffee. When you get to really pursuing the best cup of coffee you absolutely must consider the water you are using.

Total dissolved solids (TDS)

This is a measure of how much stuff (typically calcium, magnesium, and sodium) is dissolved in your water. It is often measured in ppm (parts per million). It may also be reported as mg/L -- which to all intents and purposes is exactly the same thing.

There are other fine points about Ca/Mg ratios for ideal extraction, but learning about your TDS levels is almost certainly the first step.

I live in Tucson, Arizona and we have very hard water. I was amused to learn that San Diego, California thinks they have hard water. Well their water is hard (typically about 250 ppm dissolved solids). Tucson however has water almost twice as hard (450 to 500 ppm is typical). You can almost certainly find a water quality report for where you live, or you can buy an TDS tester. The tester might be useful if you want to test bottled water or start mixing RO water with tap to get a target TDS value.

For comparison, water in New York has 30-40 ppm TDS.

Have any comments? Questions? Drop me a line!

Tom's coffee pages / tom@mmto.org