Replicating Toronto Tap Water

The following is an account of an experiment I did in April 2020.

The Context

I had been messing with water for two years, adding minerals to pure water and trying all sorts of different brands, with varying results. I was having fun, but I knew there was better water out there than what I was making, buying, and getting out of my tap. As I was reading Late Steeps, Marco Gualtieri’s tea notes blog, I noticed he seemed to be getting amazing sessions with aged teas like the 2004-06 Yang Qing Hao productions. I’m aware that now his opinions of those teas have changed a bit, but back then he was enjoying them, getting tons of intense flavor and engaging energy. My experiences with Yang Qing Hao were less stellar, more boring and flat. I started to wonder… what if it was the water? Marco lives in Toronto and was using tap water usually in his older reviews. I looked up the water quality report and thought,

What if I could make Marco’s tap water in my own apartment?

The Process

The first thing I had to do was figure out the mineral composition that I was going for. The water quality report has minimum, maximum and average ranges for each of the relevant mineral ions; for example, the calcium content is between 31.1 and 38 mg/L, with an average of 35.6. I decided to aim for the averages, and see if it led to any problems. I used a slightly modified version of the Khymos mineral water calculator to convert my target ion concentrations into a mineral recipe that I could use.

(Ignore the carbon dioxide and pH, they are wrong, and also it’s not grams on the right column, but milligrams)

The ion charges didn’t match up, so I let the calculator compensate by adding bicarbonate to balance it out. 118 mg/L of bicarbonate was still within the range on the water quality report. This water is very heavy, and pretty hard. However, the hardness is higher than the alkalinity, which basically means that the flavor won’t get eaten up by excess bicarbonate. In general, the hardness to alkalinity ratio should be above 1 to prevent dullness of flavor. However, Icelandic glacial is decent for tea and has a hardness to alkalinity ratio of 0.85. This toronto water replica has a ratio of 1.32.

The amount of each mineral I had to add per gallon was all the way on the right column, in milligrams. I needed seven ingredients in my water to get that Toronto profile. My plan was to add them one at a time until I was done, pretty simple. If you add them all at once, there’s a chance they might react in some negative way.

The gang’s all here

The first five minerals, NaCl, KHCO3, MgCl2-6H2O, MgSO4-7H2O, and CaSO4-2H2O, dissolve fairly easily in water. However, the last two ingredients, MgCO3 and CaCO3 (chalk), are insoluble. So what did I do? Khymos instructs to carbonate the water – put simply, this produces carbonic acid which reacts with CaCO3 and MgCO3 to form soluble/aqueous Ca(HCO3)2 and Mg(HCO3)2. This works, but you end up with bubbly water, which I didn’t want to use for tea – I wanted to simulate what someone in Toronto would get out of their tap.

Bubbling and Debubbling


Luckily, the local Publix supermarket had Syfo Seltzer, a Reverse Osmosis carbonated water with 0 mineral content. My strategy was to make two concentrated solutions: I dissolved a gram of chalk in one bottle and 500 mg of MgCO3 in the other bottle, left it in the fridge over two nights, and rotated the bottles every once in a while until they were clear. Then, when it was time to make the water, I used a winemaking air pump to bubble air through each of the concentrates until the solution reached a pH of 8 or above, meaning all the dissolved CO2 was basically gone. I tried using a vacuum chamber for this another time, but it didn’t seem to work as well.

pH 8!

Making the Water – Putting it all together

A pinch of salt

It was then an iterative process of measuring out minerals, dissolving them in 0 TDS RO water, and then pouring that into the big jar.

Et cetera

After the first five minerals were added, it was time for the CaCO3 and MgCO3 concentrates. I simply measured out the appropriate amounts of each – one ml of the CaCO3 concentrate contained one mg of CaCO3 (in a way) and one ml of the MgCO3 concentrate contained 0.5 mg MgCO3.

This is only some of the chalk concentrate – there’s a lot in this water!
Pouring it in, almost done!
There are ions in this water is what this reading means

The TDS (Total Dissolved Solids) measured 148, even though the calculated TDS was 232. Quick note about TDS meters – they measure conductivity and multiply that reading by a constant to estimate the TDS. This water is less conductive per mg of TDS than the solution that the meter’s coefficient constant is based on. Bicarbonates are much less conductive than chlorides and sulfates. My meter’s coefficient is actually smaller than the commonly accepted one, too. So, that TDS reading was nearly meaningless, and the water was likely actually the proper TDS.

Taste of Toronto

I’ve never been to Toronto, but the finished water had a nice, natural mineral taste. It really didn’t taste synthetic, and was quite full and soft. I was impressed! The whole process took about three days, with two hours of work total.

Making the Tea

Ok! Now that the water was finally done, it was time to test it out. I had some Yang Qing Hao Jinhao Chawang lying around, so I fired up the kettle and did a little session.

The result was astounding. I had never experienced such a concentrated, thick, powerful tea before, especially from Yang Qing Hao. It’s hard to describe, but it was so satisfying, and I felt the energy much more than other sessions. I could tell that the full potential of this tea was being extracted, but the bicarbonate was providing a wonderful softness and richness. I now understood where Marco was coming from with his praise, when before, with Nashville water and even bottled water, I never got close to this experience.

Many other sessions were had with this gallon of fake homemade Toronto water.

I forget what tea this was
Teaswelike 2001 Yellow Mark
Young Sheng – thick and sweet

It was all amazing. To be clear, this water is heavy. You couldn’t go much heavier than this and have a good experience. But the calcium and magnesium are in perfect balance, as well as the sulfate and chloride, hardness and alkalinity, just a bit of potassium, not too much sodium. This, as I understand it, is a great mineral profile, especially for a water as heavy as this. I also like lighter waters, but there’s something with this Toronto water, this density in the resulting tea, that is extremely addictive. It’s too bad it was so hard to make. I plan on making it again, with a slightly easier method that shuffles the minerals around so I only have to make one concentrate.

So yeah, this is one example of what I’ve been up to in regards to water and tea. If there ever was a tea secret, this is one – water mineral content has an enormous effect on tea. I’m not suggesting everyone should make this water, as it’s rather difficult and time consuming, and maybe not for everyone. I feel like most people know that water has an effect on tea, but don’t know what to do about it. There’s probably a 50-70% chance that your tap water, when filtered to remove chlorine taste, is good enough. But if it isn’t, it might be worthwhile to find a solution (haha) to that problem, to get the most out of that hard-earned tea. Also, it’s just fun to play around with water! This experiment really opened my mind to what’s possible with a little chemistry and imagination, and I’m looking forward to making water that’s even better than Toronto’s.

Thanks for reading!!

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