Water

The 8 TDS Difference - It's Huge For Tea, But Not Why You Think.

Brandon Kendall

25 Jun 2025 — 7 min read

Two water bottles only 8 TDS apart. The impact on tea was huge.

First, some brief housekeeping:

I am going to be doing testing with Saratoga bottled but in plastic cause I'm just not willing to spend on their price for glass. More to come on this.
I am also going to be testing a couple filters for tap water. More to come here as well.
As I write this I'm using my second bottle of Icelandic Glacial, this one in glass, on YQH Xishi Shenpin. The prior session was on CYH Cang Long. I'll be referencing this water in particular for this entry.
I've decided I'm going to write 3 kinds of articles now instead of 2.
- Tastings, likely on Tuesdays cause it alliterates and that brings me small but not insignificant joy.
- 'Pillar' articles. Deep dives, well thought out long form, very researched and poured over evergreen articles that will see updates more than once over their lifetime.
- Things like this and things in between that allow for my own freedom of expression and 'journal' feel. Much like MarshalN and those folks did, I want to maintain the ability to write as I explore in that exploratory fashion. I will then move any and all concepts possible organically overtime into pillar articles as writings amass, research is conducted and reviewed, and tiers of 'mastery' over information is gleaned (be generous with me on that term please...)
  - In summary: You'll see things like this as well as mega-articles that are very opinionated, extensive, and researched after several smaller articles on a topic pile up and I feel I have meaningful things to say in a more pointed manner.

Onto the matter at hand:

So I'm on my second session of Icelandic Glacial. I've got some initial thoughts on it, how it stacks up to Empirical Water Glacial, and some other considerations. Let's get into it.

Yang Qing Hao Xishi Shenpin 2007 Tong — *I love this picture...what a pretty tong - Xishi Shenpin, Yang Qing Hao.*

Icelandic Glacial Water w/ YQH Xishi Shenpin

It's strange, this is a tea I know very well, and while it does have a tendency to show bitter - it doesn't do so in a way I don't enjoy it.

This...does...

What's odd is, even at a slim difference in hardness of 8 TDS, I'm getting a softer experience that a layman such as myself would assume a 40 TDS difference would more likely give. As it is though, I feel like I'm having an almost entirely different tea. The bitterness is a bit more predominant; not overly so, as in, I don't find it to be a stronger bitterness or a louder one - maybe just that it's more center-stage here.

Further, that juicy apricot thing you can find in Xishi just isn't present. You can tell its ghost is here, or maybe not ghost so much as muted; almost akin to how a zini pot may suppress a top note. It's very odd.

If you know my friend Wooju over at Short Little Steeps (blog below), you know he is a well steeped gentleman in the tea community. He's been around a while.

He says that Empirical Water Glacial is fantastic for coffee, but over-extracts for tea. Arby has been using his Spring recipe for all his brews recently and was excited to have me try it, but to be honest I found that one to be very suboptimal for tea for essentially the same reason. I find the Spring to be quite a bit too heavy, and after going through 2.5 gal of it, I wouldn't use it again for tea.

I have however quite enjoyed using Glacial for the last several months to a year now, and only recently from a bad batch, decided to revisit some other water options for learning purposes. I used old, pre-opened buffer solution with a new concentrate and had to pitch the whole thing...didn't realize how much an effect that would have.

I think what I'm encountering here is one of perspectives and baselines, and...likely palates and that other magic word that sparks oh so many disagreements: preferences.

Chen Yuan Hao Cang Long Cake 2010 — *The dragon awakens! Chen Yuan Hao Cang Long.*

Icelandic Glacial Water w/ CYH Cang Long

The story behind this tea is that I got a cake recently on trade from a friend in Germany. It arrived, rested a week or so, and was found to be a pleasant and very smooth and sweet Yibang. Nothing too crazy, but a more than serviceable daily drinker and quite nice to have when one wants something soft and easy going.

Well, interestingly, when you drop the TDS by a measly 8 points: turns out it gets so soft it feels bland, boring, and like a ghost of it's former self. It's fine, but I'm not sitting on a mountain of reasonably nice to nice tea to drink it fine.

So is it pH? Is it TDS?...is it rather all BS?

I'm not really sure. I have a strong lean based on multiple years of conversation with Arby and various personal experimenting I've done, plus whatever 'tacit wisdom' I've gleaned over 5 pretty serious years, for what that's worth.

Here's my take:

It's not hardness at all. I think TDS means very little if within a half decent workable range. I think it matters much more which minerals you have and in what ratio said minerals are in proportionate to each other. After tinkering with this for over 3 years and following along and conversing with both Max and Arby at different points in time, I've gotta say - I can confirm the below information firsthand, it's legit.

Rather than try to explain all this myself, Max of Tea Secrets (his blog below also) has an absolutely phenomenal repository of information on water. Credit to him, I will post a chart from one of his articles here:

Table of different ions and their effects on water for tea. Credit to Max from Tea Secrets blog for this image and information. — *Credit to Max from Tea Secrets blog for this image and information.*

So was it really the whopping 8 TDS difference that gave such stark experience contrast on these 2 teas? No, no I don't think so.

I think we need to start talking a lot more about optimal minerals and amounts and ratios within them and stop fixating on TDS.

I also think, at least to some degree, we should be forgiving and curious when Andrew wants to celebrate his Columbus tap water, I want to brew with Empirical Glacial, and another few folks want to brew with bottles of Volvic, Icelandic, Polar Spring, and Saratoga...not to mention all the different filters...which, by the way: will have different impacts on different tap waters that go through them.

I have one more place I want to take this, and then I promise I will try not to make every article about this topic.

What is subjective and what is objective?

I'm honestly not really even sure how many of us would agree that the water one tends to enjoy with tea is subjective. I feel like there'd be a chunk of people out there that would loudly and proudly say there is such a thing as an optimal water for tea and that it's pretty set in stone. Usually that sort of line of thinking leads down the path of right and wrong, understanding and not understanding.

While that may be true, and I'm not fully convinced of either side on the water debate right now, I think one thing is noticeable with the Xishi:

All things equal, I'm shocked how much I don't enjoy it with an 'objectively good', or even 'better' water than Arby's Glacial.

I know this tea very, very well - and it's crazy that, if this was the water I was using every day - I wouldn't drink it! I mean, heck, this cake was $1400 a piece at one point...it's YQH, it's got Bohetang region leaf in the blend, and it's got really high praise from people that like the brand.

Of course you'll always get people that just hate YQH, whether founded or not and whether tasteful or not, doesn't really matter and I don't really care.

I think that's sort of what I'm trying to say here with the water discussion. If I prefer tea and find it to be better with slightly harder water, does that mean my tea is bad cause it isn't as good with soft water? Does it mean that I'm unknowledgeable and just fundamentally off base in a swath of areas?

I don't know, I really don't - I'm not being snarky. I do know that I love tea and that Taiwanese locals have told me I know Chinese pu'er tea better than most local tea lovers in Taiwan. Yet...I've also been told that doesn't mean anything cause "Of course you are, most mainlanders don't understand tea." and a lot of the sellers don't either.

At the risk of making every article an argument against our constant human need to divide and be superior to each other, I'll digress here and live to unify another day. Just do yourself a favor in the meantime, get yourself some good water.

Wooju's (Seo) Blog