Humanity and the Water Filtration Problem

Man, the difference between tea made with low-hardness water and water filtered in these filter pitchers (which are honestly too expensive even if they were free) is night and day. For a long time, I had a passion for seeing what the deal with these filter pitchers is and how they perform, and to test different filters, two years ago I went and bought a TDS meter and went to town on them, testing the output of different filters. The important point is that TDS is not the whole story, but for my curiosity and the tool I had, it was enough.

Among the famous filters, I have tested BWT and Philips so far (I want to post the details of each extensively later, so for now, I'm just mentioning the brand names), and their output was not at all what I expected. Aside from the fact that the output water hardness level was not stable at all, what was strange to me was that in some cases, the water hardness even increased (of course, some of these filters like the BWT magnesium filter add some minerals to the water themselves, and this can increase the water hardness). The last time I tested the Philips filter, it had reduced the water hardness once, bringing it down from 240 to 180. But other times it was either the same or even more. And naturally, I tested these experiments several times under conditions as identical as possible. BWT still gave a better result, although it was also still around 200, and 200 is a relatively high hardness.

The annoying point of the story was two things:

1- I keep boiling water in a stainless steel thermos. And after a few days (between 10 to 15 days), I could feel the water scale in my tea, and well, I saw that tiny sediments had collected at the bottom of the thermos. Cleaning the thermos and electric kettle with something acidic like vinegar or lemon juice really required patience. And feeling the sediment in my mouth while drinking tea was truly annoying to me.

2- The tea I brewed formed oily spots on top. I didn't know what it was, so I asked my reference and source of beverage and food science and close friend, Peyman, and he, as always, sent a multi-ten-minute voice message to explain the matter to me. If you'd like, Peyman has a few detailed voice messages (about half an hour) solely regarding the science behind tea, brewing it, and its hygiene. I can post it here later, with or without editing :). The summary is that water hardness causes this issue. In fact, the calcium and magnesium in the water form a complex with the tea polyphenols that appear as thin layers of fat on the water (also called tea scum) and also darken the tea's color.

In short, these were very annoying to me, and I said let's put aside the resistance and go for bottled and mineral waters. The reason for my resistance was that bringing boxes of water and managing the empty bottles is really a hassle in itself. Anyway, today I went and got two boxes of mineral water. I went for Sant’Anna because I wanted to see how the output would be if we lower the hardness significantly, and the result was truly amazing. When I measured the hardness of this water, my mind was blown. The TDS meter showed the number 15. I had never seen manufactured water with this level of hardness before. And tonight we brewed tea with it, and well, the result was truly excellent. A tea that was nicely colored, clear, light, and tasty. We even performed a single-blind test :)) Our friend had come to our house tonight, and well, he has drunk tea here many times. Tonight, without knowing we used mineral water, he spoke up about how good the tea had become. Of course, after these run out, we will switch to water with a higher hardness because the lower the water hardness, the more its taste leans towards bitterness, and more importantly, low minerals disrupt the body's electrolyte balance, which is a disaster in itself. We will probably go for the Levissima brand, whose water hardness is around 80.

P.S.: I didn't get a chance to take a picture of tonight's tea. Meaning, when I got to it, I had no time left to pour for myself. I quickly gulped down my two glasses.

Tea scum And the water hardness before and after filtration with a filter (the one that is higher is the water filtered with the filter)