If your tap or well water has impurities that must be filtered out such as high levels of hardness, or iron that necessitate a water softener and you then wish to remove the sodium introduced by the softener (because you have high blood pressure or a family history of high blood pressure) or, if there are any number of contaminates, a reverse osmosis system is frequently necessary. However, RO water is not the best for brewing tea:
“Putting aside for a moment the influences on tea before it is dried and finished, tea also goes through a second “flavoring” process as you brew it and sip it. First, you have to consider the water you use, and take into account all the flavors it offers. Straight reverse-osmosis water is never recommended in tea brewing, because it is so pure that it tastes flat. If you use a spring water or filtered tap water, the flavor of this water will come through, contributing sweetness, texture, or in undesirable cases, metal and chemical traces to your tea. No matter what, you are “blending” your tea with a water that you hope will help bring out the best that the tea has to offer.”
Published on April 26th, 2012 by David Duckler
If an RO system is necessary for your residential water and you want to enjoy your tea without hauling bottled spring water, then you may wish to consider adding a re-mineralization filter after your RO system such as the Impact Alkaline to bring your TDS level into the following range:
“Water with 50 – 150 ppm total dissolved solids (TDS) or 1 to 3 grains hardness provides the best results, according to the Tea Association of the USA." http://www.teaandcoffee.net/0609/tea.htm
The TDS of our RO water before the remineralization filter, typically measures ~24 PPM.
We use a HM Digital: DM-2: In-Line Dual TDS Monitor (https://steepster.com/teaware/hm-digital/100243-dm-2-in-line-dual-tds-monitor) to monitor how much the Impact Alkaline is able to raise the TDS level of our reverse osmosis system. Today for example, the TDS level after the Impact Alkaline is 84 PPM, which puts us right in the middle of the 50 to 150 PPM range recommended by the Tea Association of the USA. I track this metric over time.
Please be advised, that a number of factors affect how much a remineralization filter like the Impact Alkaline will raise your TDS including: age of filter, water pressure, water temperature etc. As they say, “YMMV”.
Highly recommended based on the taste of both our water and our tea.