The Tea Curious Open Water Recipe: The Most Kickass Water You Can Make At Home

RIE TULALI | 11 MIN READ

TEA & WATER QUALITY

Published: 11/15/2020
Last Updated: 11/15/2020
Water Recipe Version: 1.0.0

After 8 years of water study and more than 100+ waters tested — as well as the help of many, many friends and fellow tea nerds — we're just over the moon to be able to share the Tea Curious Open Water Recipe with you!

More than just a crazy science experiment, our Tea Curious Open Water has really become a beloved, reliable friend in our tea practice, helping us bring out the absolute best in every tea. It's given us incredible confidence and control over the brewing process. We hope it treats you just as well at your tea table. :)

Enjoy!
- Rie & Steven, Tea Curious

About The Recipe

The Tea Curious Open Water recipe is a free, open source, and super accessible formula for brewing water you can make right at home. The recipe was initially created by your tea friends over here: me, Rie Tulali, and my partner, Steven White, as a way to achieve more control and consistency in our brewing process.

We took lots of inspiration from in the coffee world to make this recipe, where DIY water formulas have been pretty much mainstream for years. And while you can find tons of awesome, super dialed-in recipes for coffee brewing water online, tea does require slightly different water than coffee does: and so we created the Tea Curious Open Water, made specifically for tea. ;)

To make this water, we use common salts, like epsom salt and soda ash, that help us capture the same mineral composition found in soft spring water — the type of water that tea sage Lu Yu loved the most for tea, and also the type of water that we happened to prefer in our hundreds of experiments as well. :)

All in all, the recipe costs just cents per liter to make, takes just a few minutes to prepare, and can be made with ingredients that are readily available online or at local stores.

This recipe is designed to perform well with the whole spectrum of teas, from white tea to oolong to shou pu'erh, so you can just make the base recipe and stick with it, pretty much forever. :) However, it can also be easily customized to boost flavor, texture, aroma, and/or aftertaste based on your needs and preferences in tea, as we'll discuss below.

[Note our bias as the creators of this formula though: we're fanatics of sweet teas with lots of texture and aftertaste, so this recipe will likely skew accordingly! ;)]

Finally, while we've relied heavily on textbooks, meticulous experiments, and over 100+ peer-reviewed articles on tea & water to develop this recipe, we're not trained chemists or hydrologists by any means. Instead, what we share here is the result of thousands of hours of testing, learning, and on-the-ground study by a couple of professional tea nerds, who simply became water fanatics by necessity. ;)

Why "Open" Water? Our Open Source Principles

Open Water? No, no, not the movie...

We named the Tea Curious Open Water Recipe in the way we did because it's intended as an open source project: this means that it is free to use, alter, improve, and/or republish, for both personal and commercial purposes. (You can learn more about open source principles here.) This is because while there are many proprietary formulas for water out there (including many remineralized bottled water brands), we specifically chose to leave our recipe open source and readily available so that anyone can make cheap, sustainable, and utterly fantastic water for tea. :)

No secret formulas here. Oh and also, no more plastic bottles!

(I relied on bottled spring water for years, so I'm just paying back my dues, yo.)

So if you'd like to use this recipe for:

  • your own personal brewing use
  • a blog, article, or website
  • in a tea space + cafe + other commercial and/or public space
  • as a base for your own water recipe

Go right ahead! Just drop a link + shoutout back to this page, if you can. :)

As an open source project, this also means that there'll be lots of space for further development and improvement over time. We'll continue to update this page as we improve on the recipe and our research in water, along with a list of contributors and references found below.

We hope you join us in making affordable, sustainable, and reliable water the standard for our cozy little tea community. :) If you have any questions or contributions, just email me at hello@teacurious.com.

Brewing Water 101: A Quick Lowdown on Good Water For Tea

When it comes to all the fancy tools and techniques we have in the tea world, I think water is the most underrated -- and the most powerful. I love the performance of my Yixing clay pots and Tokoname kyusus as much as the next person, but I still think that water is more important.

After all, even the best pots are used for just one or two types of tea... in play for just a small portion of your total tea brewing career. Your water, though? It makes an impact on every single tea you make. Like, forever.

(And if you need more reasons to get serious about water, don't worry, we got plenty: check out 5 Reasons To Test The Water You Use To Brew Tea.)

But if water is so important, then what's the best water for brewing tea?

Good question!

In general, tea prefers relatively soft spring and artesian waters. We've seen this both in the extensive testing we've done over the years (again, hundreds of experiments), and also in both traditional and modern sources on tea & water. Some examples of soft spring & artesian waters include Poland Spring, Icelandic Glacial, Fiji, and Volvic, many of which have been popular brands in the tea community for years.

If you're lucky, you may also have good water right from the tap, but this varies a LOT based on location, weather, and your city's water treatments.

And really, it's hard to tell whether a water is good for tea or not until you test it. For example, Evian and Acqua Panna are tasty waters that might do well in a fine dining setting, but good drinking water and good brewing water are not always the same thing. Many world-famous springs and bottled water brands (Evian and Acqua Panna included) are actually pretty terrible at making tea, so it's not just so much about price, brand or origin: it's about the mineral content.

Good water for tea has: (A) the right kinds of trace minerals, and (B) the right amounts of them.
Let's take a closer look, shall we?

The Best Minerals For Brewing Water

Water is mostly HO, but along the way it naturally picks up a whole slew of trace minerals that change the way it tastes - and the way it performs with tea.

There's are dozens of trace minerals that can be found in water, but we can focus on just a handful that are the most important for tea. These are: calcium, magnesium, sodium, potassium, chlorine, sulfates, and carbonates. Now, we may been spooked a lot by Big Food when we see chemical components in our beverages, but no worries — these minerals (yes, even chlorine and sulfates!) are harmless in tiny amounts and can even positively contribute to the taste of water and brewed tea.

For example, combine sodium (Na) and chlorine (Cl), and we have NaCl, or table salt, which is also what makes seawater super salty. These minerals are also routinely added back into purified water to make some common bottled water brands: Smartwater, Dasani, and Aquafina, for example, are all re-mineralized waters that are so named because their flavor comes from water additions, and are really water formulas just like ours!

Without these minerals, we would barely be able to taste anything in a cup of tea. You can test this by brewing tea in pure, reverse osmosis filtered or distilled water with no minerals: the tea will likely come out flat, imbalanced, and kinda "empty" tasting. No good!

So we need to learn how to work with these minerals, and to work with them in the right ratios.

What's cool is that we can easily work with these minerals thanks to some materials we use everyday in our homes: salts like sodium carbonate (soda ash), sodium bicarbonate (baking soda), magnesium sulfate (epsom salt), and calcium chloride (canning/jarring salt) are safe and readily available sources for these key minerals.

In the right ratios, these minerals seem to play very specific roles for us in tea. From our tests, we've generally observed:

  • sodium carbonate (Na₂CO₃) and/or sodium bicarbonate (NaHCO₃) both boost texture, sweetness, and aftertaste, making teas taste round and lingering
  • calcium chloride (CaCl₂) boosts sharp and cooling characteristics, making teas taste crisp and refreshing
  • magnesium sulfate (MgSO₄) boosts complexity, fragrance, and some of the more "bassy" notes, making teas taste more distinct and interesting
  • potassium bicarbonate (KHCO₃) boosts the boldness and strength of teas, making teas taste more upfront and punchy

However, we also found that too much or too little of these mineral salts can also throw off the balance of the tea, making teas taste chalky, dull, and/or sour. So we gotta get REALLY precise about these minerals, which we can do by looking at their component ions.

Take, for example, soda ash (sodium carbonate). This salt is actually a combination of both sodium (Na) and carbonate (CO₃) ions, which carry a positive and a negative charge respectively. There's a LOT going on with the chemistry of water & tea extraction, but for now, we can assume that these charged ions interact a lot with the components in the tea, which is why the same tea can taste so different with various waters.

Now that we're aware of these ions, let's dial them in to get just the right water.

Our Target Profile For Tea Curious Open Water

PPM, which means "parts per million", is the standard way we can measure trace minerals in water. For example, a water with 10 PPM calcium just means we have ten calcium (Ca+) ions for every one million water molecules (HO). What a difference even a tiny amount can make!

In general, tea prefers a relatively low concentration of minerals, with a maximum of about 150 PPM of mineral content. Any higher, and you'll likely start getting super heavy, muted teas that also leave hard water stains like the plague!

Even better, though, is if we hit our preferred range of 20-100 PPM, with white and green teas generally performing better on the lower end, and heavier teas like black tea and shou doing quite well on the higher end.

We've designed the Tea Curious water to hit right in the middle of that range, at around 50-60 PPM, with the following measurements:

  • Sodium carbonate (Na₂CO₃): 0.012 grams / 1 L
  • Calcium chloride (CaCl₂): 0.018 grams / 1 L
  • Magnesium sulfate (MgSO₄): 0.025 grams / 1 L
  • Potassium bicarbonate (KHCO₃): 0.012 grams / 1 L

Together, this leaves us with a water with (roughly) 7 PPM calcium, 2 PPM magnesium, 5 PPM sodium, 5 PPM potassium, 11 PPM chlorine, 10 PPM sulfate, and 14 PPM carbonates and bicarbonates: or around 58-59 PPM, right in our target range after the slight variation you'll get in even the most accurate home scales.

By now you might be wondering why this water is so dang light, especially compared to the targets specified in the coffee industry, but this just seems to be what tea prefers: as a leaf rather than a fruit + roasted bean, it relies on slightly different mechanisms to get to the ideal brew.

In fact, there's evidence that excess calcium and magnesium can inhibit tea extraction, so it's important to keep these ions at a Goldilocks level of concentration. :) Let's get them going!


How To Make Tea Curious Water

Materials & Tools You'll Need

  • Calcium chloride (CaCl₂)
  • Sodium carbonate (Na₂CO₃)
  • Magnesium sulfate (MgSO₄ * 7H₂O)
  • Potassium bicarbonate (KHCO₃)
  • "Blank" water — purified, reverse osmosis filtered, or distilled water all work just fine. Can be purchased at the grocery store, at refill stations, or at specialty water stores. Can also be made at home if you have a RO filter without remineralization.
  • Weighing Scale accurate to 0.001, recommended to weigh out precise amounts of minerals
  • Water container (standard 5 gallon/18.9 liter container), for water refills & to store water in

Total starting cost: Around $50 USD

Making Your First Batch

To make Tea Curious water, start by measuring out the appropriate amounts of each mineral for the amount of water you need, based on the following chart:

To create this water, start by measuring out the appropriate amounts of each mineral for the amount of water you need.

For example, for 5 gallons (18.9 liters) of water, weigh out:

  • 0.226 grams of potassium bicarbonate
  • 0.34 grams of calcium chloride
  • 0.472 grams of magnesium sulfate
  • 0.226 grams of sodium carbonate
  • Mix with the water! Allow 5-10 minutes to completely dissolve, if needed.

You can stop here and have a perfectly great water for tea -- seriously! However, there's one more component that, while a little more tricky to get, is just the cherry on top on this already-awesome water, and that's amorphous silica. I especially recommend it if you're a bit of a texture & aftertaste junkie like we are with our teas.

Refer to the table above for silica/silicon dioxide measurements. For example, for a 5 gallon / 18.9 liter container:

  • 0.189 grams of amorphous, food grade silicon dioxide
  • (Optional) Non-crystalline, amorphous silica (do not use crystalline silica!)
  • Mix with the water, together with the other ingredients! Allow 5-10 minutes to completely dissolve, if needed.

But wait, why silica?

Silica, a nickname for silicon dioxide, might be surprising to find in this recipe, even as an optional additive. Like, hold up, isn't silica dust the stuff that's dangerous to inhale? And is it dangerous in water?

I never thought I'd be adding silica to my water either, except that I kept stumbling upon this compound everywhere I tasted good tea. First, silica popped up as the main component of some of our favorite ceramics in teaware tests, including feldspar porcelain and zisha purple clay, used for Yixing teapots. Cool story, but okay...

But then it popped again as a key component in bamboo charcoal, something we already habitually use to make better water for tea.

And then silica showed up one more time in the artesian waters from the Pacific that dominated our water experiments with bottled water: Fiji, Trader Joe's New Zealand Artesian, and 1907 were all incredible waters that were naturally high in silica.

And what they did for tea was something no other water could do, which was to boost rounded, soft textures and long, lingering aftertastes. It made high mountain oolongs taste even more like clouds!

I was hooked on these high silica waters, and I wanted to learn how to make 'em. Luckily, I found through our research that the type of silica found in natural waters, orthosilicic acid, is a totally different beast than its insidious cousin (crystalline silica, from quartz) that we hear about all the time in workplace lawsuits.

The type of silica we find in water is safe for consumption and again exists naturally in many pure, artesian waters like Fiji. (Fiji has more than 90 PPM silica!)

Oh, and did I mention it's just amazing with tea?

The only downside? Well, no one sells a food grade, non-crystalline silica for retail use, so the only one we have is one we sourced specifically for our water project — and for now, it's the only reliable way we know of to get a good, food grade, soluble silica.

Trust me, Steven and I didn't get into this just to deal baggies of white powder, but we just love the impact of silica so much that we want to make it available for anyone to use. If you're interested in picking up some food grade silica from us, just leave us your email here and we'll let you know when it becomes available. Just one bag is enough to last you literal years of water formulation. :)

Price & Sustainability

Beyond just the incredible teas you'll brew up with this water, it's also remarkably affordable and sustainable to make at home. I'll be posting up a detailed breakdown of the price calculations soon, but in a nutshell, it'll cost you just 50 USD or so to start formulating water at home — and that investment will last you a looooong time, I promise.

And assuming a standard 5 gallon (18.9L) refill of distilled/RO purified water costs you $1.35, as it does for us, you'll be spending a little less than 10 cents a liter (or around 25 cents per gallon) for excellent water. Woohoo!

In comparison, the same 5 gallon (18.9L) amount of the best performing bottled water, Trader Joe's New Zealand Artesian, would cost $14.93 (almost 11x more expensive!), and another favorite, Fiji, would cost $37.61 (27x more expensive!).

And a HECK of a lot more plastic too. No thanks. We'll stick to our beloved water recipe. :)

More than a crazy science experiment, the Tea Curious Open Water has become a dear and reliable friend, always making sure that our teas come through with their absolute best. We hope you enjoy working with this amazing water just as much as we have. Cheers!

FAQ

We'll be updating this very soon with more on the Tea Curious water recipe and how to work with it, including any troubleshooting and FAQs that come up from our community. If you have any questions, concerns, suggestions, math corrections, or just happy nerd giggles to share, let us know at hello@teacurious.com. Thank you!

To be added soon: FAQs, References, Links That Are Not Amazon, more on sustainability

Want to learn even more
about water?

If you're just looking for reliable water to use for tea, then you'll find that the Tea Curious water recipe will be MORE than enough to work with. :) Seriously -- it's a workhorse!

But if you'd like to dive even deeper into the study of tea & water, then we'd love for you to join us on our upcoming course: Water For Tea, launching in December 2020. This step-by-step course is designed for tea professionals and serious enthusiasts who want to fast-track their understanding of water for better brewing, while also exploring the history, science, and critical techniques underlying good water.

We'll only be offering a limited number of spots for founding members this December, so if you're interested, please make sure to sign up for our wait list! It's gonna be awesome.

Water is just the most underrated secret weapon in the tea universe, y'all.
Well, not-so-secret anymore. ;)
Cheers to better water and better tea!

Rie + Steven

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About the Author

Hey there, I'm Rie and I'm a professional tea nerd. I share the techniques and strategies we've used to seriously level up our tea game so you can get super confident with tea too!