Water Guide (WIP)

Welcome! They say that tea is 99% water, but this misses the point; what matters is the ~0.01% of the water that isn’t water. This guide will explain what these substances are, what they do, and show you how to build your own tea water from scratch. After reading this guide, you’ll be able to make water recipes!

Designing and building waters is something I do as a hobby. I am a self-taught water chemist – I began this hobby in 2017 with the goal of improving my tea sessions and furthermore understanding water. Water, as I have discovered, is deep. But, it can also be clear and simple at the same time.

Thank you to everyone who has tried waters designed by Arby and me, including Glen from Crimson Lotus Tea, James of TeaDB, and everyone on the tea Discord. It’s an honor to interact and contribute to the tea community.

This guide is also meant to illustrate why certain waters are better with certain teas, basic relevant water chemistry concepts, and how mineral content relates to the sensory experience of tea drinking. This will all come soon.

Also, there are no water recipes yet released that use the Sodastream. This is to make water recipes easier and faster to make with a lower barrier of entry, cost-wise. The waters that don’t use the Sodastream don’t require calcium or magnesium carbonate, and work pretty well. If you want to bust out the soda maker, check out the Toronto water post, there is a recipe there.

If you want to skip the making part and just have concentrated water recipes delivered to you, please order Arby’s crafted waters at empiricalwater.com.

You will need:

Distilled or Reverse Osmosis water <5 ppm TDS

A TDS/EC meter*

A milligram scale

Silica gel packs (recommended)

pH testing drops (recommended)

A Sodastream water carbonator (for recipes with CaCO3) OR Syfo Original Seltzer (if you can find it, also only for recipes with CaCO3)

If included in recipe**:

Sodium bicarbonate

Potassium bicarbonate

Magnesium chloride hexahydrate

Magnesium sulfate heptahydrate

Calcium sulfate dihydrate

Calcium carbonate

Calcium chloride

Sodium chloride (sea salt is 30% MgCl2, and regular salt has anti-caking agents which don’t dissolve)

Silica concentrate

*(TDS meters do not accurately measure TDS. They measure electrical conductivity, which is different for every ion, and then convert it to TDS by multiplying by some arbitrary constant. 100mg of table salt would measure twice as much as 100mg of baking soda on a TDS meter, even though they are both 100 ppm TDS. However, if your TDS meter also measures electrical conductivity, it is useful to check the accuracy of your homemade water. TDS meters are also useful to check your pure base water to make sure it is as close to 0 ppm TDS as possible.)

**if you don’t want to support amazon, you can find these minerals on https://puresupplementsco.com/ and the silica concentrate on https://www.eidon.com/

Storing your minerals:

Keep the minerals in sealed ziploc or mylar bags. Use a silica gel pack to store in your CaCl2 bag, and another for your MgCl2, as they both deliquesce, which means they spontaneously take on water from the air and will turn into a clump, or even worse, a puddle, if exposed to moisture. Without a silica gel pack, you can’t be sure that the water content of the mineral is consistent. Therefore it’s best to keep those two minerals as dry as possible.

How to add the minerals:

  1. Assemble your mis-en-place. Gather all the minerals you will need for the recipe, as well as your pure water, scale and scoop.
  2. Place the scoop on the scale and zero the scale.
  3. Take the scoop off the scale and look- there will be a negative number – remember it!
  4. Measure the first mineral onto the scoop until it reaches the required amount – for example, for 73 mg NaHCO3, my scale reads 0.073 g.
  5. Make sure when you remove the scoop, the negative number from step 3 is still the same! If not, something went wrong with the scale, or some minerals are spilled. To troubleshoot, make sure there’s no static electricity buildup on the scoop or the scale dish. Use a very slightly damp tissue to clean the scoop and dish, and start again when it’s dry. If you hover the empty scoop over the scale and the value changes, there’s static buildup.
  6. If the negative number is the same as before (+/-2mg) add the mineral to your water. Immerse the scoop in the water and stir. Make sure all of the mineral has been rinsed off of the scoop into the water, then dry the scoop. Wait around 5 minutes or until you think it has dissolved, then move on to the next mineral. Large crystals and gypsum both take a long time to dissolve. Stirring and shaking tends to help speed things up.
  7. Repeat steps 4-6 until all minerals have been added, and you’re done! Taste the pure mountain spring water that you’ve just artificially made.
  8. If your recipe has calcium carbonate, you need to make a concentrate. Put 500mg CaCO3 into a sodastream bottle with 800ml distilled or RO water, and carbonate aggressively. Make sure it doesn’t overflow out the top. Add 200 ml RO/distilled until the 1L bottle is full, then place in the fridge on its side. Rotate the bottle every few hours until the solution is clear and there is no powder left floating around. This should take around 24-36 hours. When a recipe calls for CaCO3, use a gram scale (like the one you measure tea leaves with) to measure double the amount called for in mg. For example, if you need 86 mg CaCO3, you add 86*2=172 grams concentrate into a pitcher on your gram scale, then add that to your water. By the way, you have to remove that amount of water in mL from your jug at the very beginning to make room for the concentrate. This should really be step 1, shouldn’t it. Anyway, you’ll end up with slightly carbonated water, but honestly, after boiling the water for tea, the carbonation goes away.

About the Minerals:

Water is water and more – all natural water contains some of the seven major dissolved ions:

IonShort form with chargeEffect on WaterEffect on Tea
CalciumCa++Smoothness, presence, sweetnessCore taste, sweetness
MagnesiumMg++Brightness, presenceFruitiness, forwardness
SodiumNa+More complexity, softer, richnessMildness, umami
PotassiumK+Lowers viscosityDepth, astringency
BicarbonateHCO3-BodyBody, depth, smoothness
SulfateSO4–Complexity, bitternessStrength, complex taste/feel in throat, bitterness, too much is “dirty”/aggressive
ChlorideCl-Sweetness, roundnessSweetness
Seven Major Ions

With ions, you must always add two at a time. Even nature has to add two at a time. So, you can use compounds such as:

Common NameFormulaEffect on WaterEffect on Tea
Baking SodaNaHCO3Less present, warmer, richer, watery, muddled (too much)
SaltNaClRounder, sweet, less refreshing
Potassium BicarbonateKHCO3Thinner, astringent, deeper, sharper, “X factor”
GypsumCaSO4.2H2OForward, bitterness, strength, sharper, complex, vibrant, richness, dirty (too much)
Calcium ChlorideCaCl2Forward, sweetness, roundness, clarity, sliminess (too much)
Epsom SaltMgSO4.7H2OForward, vibrant, electric, pizazz, bitterness, sweetness, strength, aggressive (too much)
Magnesium Chloride HexahydrateMgCl.6H2OForward, strength, clarity, hollow and bitter (too much)
Calcium BicarbonateCa(HCO3)2(aq)Volume, structure, overall strength, clarity
Magnesium BicarbonateMg(HCO3)2(aq)Stronger volume, structure, clarity, extra presence


Silica is found in almost all natural waters. It’s what glass is made of, as well as quartz, and is found in silicate rocks. Despite being nearly insoluble, with a saturation of around 100 mg/L at room temperature, the effect of dissolved silica is significant. It increases the “voluminousness” of the water, as well as the tea that is made with it. Unlike the seven major ions in water, it’s not really an ion, and dissolves in water as silicic acid. To me, silica also makes water feel more cohesive, refreshing, sweet and satisfying.

Dissolved Gases:

The main dissolved gases in water are oxygen and carbon dioxide. A majority of natural waters are saturated with respect to dissolved oxygen, around 8-10 mg/L. I have to research more with the dissolved oxygen concentrations in water made at home. I have a test kit for that which I haven’t used yet.

Carbon dioxide is very significant, and determines pH – more CO2 means lower pH. Waters can have tons of CO2 (carbonated water) or none at all, or in between. No CO2 tends to taste flat, some CO2 can add volume and brightness/forwardness, too much and you taste a different kind of flatness, e.g. staleness/bitterness. Too much can also make the water “fuzzy” or “fluffy”. When you boil water, CO2 escapes into the air, but in my experience, not all of it at once. If you’re careful with your boiling, some should stay in. It’s complicated. Chem-wise, CO2 turns CO32- ions into 2 HCO3- ions.

Glossary of Terms:

Hardness – Concentration of dissolved Calcium and Magnesium ions. This is expressed in mg/L CaCO3 – this doesn’t mean that it is CaCO3, but you have to convert to that unit. To calculate hardness, the formula is approximately: Calcium concentration (in mg/L) * 2.5 + Magnesium concentration *4.1.

Alkalinity – Concentration of dissolved bicarbonate ions. Like hardness, this is also expressed in mg/L CaCO3. To calculate, multiply the bicarbonate concentration in mg/L by 50/61.

Hardness to Alkalinity Ratio – The ratio of hardness to alkalinity. The higher this value is, the more acidic/bright/vibrant the resulting tea is. The lower it is, the smoother/thicker/darker it is. What’s the optimum value? It depends! But probably above 0.8 and below 1.5.

Sulfate to Chloride Ratio – The molecular ratio of sulfate to chloride – a common consideration among beer brewers, this ratio affects extraction of bitterness vs sweetness. High sulfate to chloride emphasizes rear throat bitterness, strength and complexity, while more chloride to sulfate brings out sweetness, smoothness and roundness.

More coming soon (Last updated 10/5/22)