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July 29, 2019 /
DIY Water Recipes Redux

A couple of years ago, we published a method for making your own water recipes, using concentrated mineral solutions, diluted with deionised water, to make a range of waters with different hardness and alkalinity. This post updates this, with new recipes that allow you to easily target a specific GH and KH in your water.

We’ve also added in a calculator that allows you to work out what will happen if you add minerals to existing water, rather than just deionised water. This will be useful to anyone in soft water areas who would like to remineralise their tap water, for example.

This post has been update to correct a slight error in one of the calculations: thanks to Johannes Wintz for putting us straight!


The Concentrate Recipes

You’ll need the following before you start:

  • Baking Soda – NaHCO3, Sodium Bicarbonate (not to be confused with baking powder)
  • Epsom Salts – MgSO4.7H2O, Magnesium Sulphate.¹
  • Deionised/Distilled/Ultra-pure water
  • Scales (accurate to 0.01g)
  • 3 x ~1L water containers (preferably glass, and odour/residue free)

The Buffer Solution

Dissolve 1.68g of sodium bicarbonate in 1L of deionised water. This creates a solution with a KH (as CaCO3) as close as we can get to 1000ppm.

The Hardness Solution

Dissolve 2.45g of Epsom salts in 1L of deionised water. This creates a solution with a GH (as CaCO3) of 1000 ppm.


Create Your own Water Recipe using Deionised water

Using these two solutions with deionised water is very simple. To get your desired KH and GH, you can simply use that number of mls of each solution, then make the total volume up to 1L with deionised water.


Mineralise Pre-existing Water

If you prefer to add hardness or buffer to existing water, perhaps to take advantage of the calcium or other minerals already in the water, then you can use this calculator to work out what the final KH, GH, and TDS of your water will be. This is helpful if just want to boost the hardness of your favourite bottled water, for example, or to mineralise your tap water if you live in a soft water area.

To use this calculator, measure the KH and GH of your existing water (and optionally your TDS), then put these numbers into the calculator along with the amounts of each solution you plan to use.

You’ll see that adding 10ml of a solution doesn’t simply increase KH or GH by 10, like it does with distilled water. This is because the solutions themselves dilute the water that you started with. By tweaking the amounts of each solution that you use accordingly you should be able to work out what amount will get you your target GH and KH.


Why are these Recipes Different?

Our previous solutions were designed to give you 1g/L of magnesium or bicarbonate ions, respectively. However, this is not the way that we usually measure hardness and alkalinity.

Rather than give the concentration of the ions directly, both hardness (GH) and alkalinity (KH) are usually measured in calcium carbonate equivalents. In other words, it tells you how many parts per million of calcium carbonate you would have, if all the hardness or alkalinity was due to calcium carbonate alone.

It’s measured this way because simple drop test kits can’t distinguish between calcium or magnesium ions, so it’s easiest to assume it’s all calcium. This means that when we start using magnesium or sodium salts to tweak the water, we need to do a bit of maths to convert those amounts into CaCO3 equivalents.

To make it easier for you to experiment with different hardnesses, we’ve altered the recipes to aim for a specific KH and GH instead. This means that you can easily target any GH or KH you like, with no conversion required.


The Water Recipes

These are the original Barista Hustle water recipes, updated for use with the new concentrates.

Recipe 1 – Melbourne

  • 11.5g Buffer
  • 23.7g Mg
  • 964.8g DI water

This is a close approximation to Melbourne water. This is very “soft” water, low in mineral content, and useful for those long filter brews or cuppings drawn out over five to ten minutes. Would also help with those darker espresso roasts that don’t need as much help extracting out flavours. 

Recipe 2 – WOC Budapest

  • 40.1g Buffer
  • 51.2g Mg
  • 908.7g DI water

This is in the target range for the World Brewers Cup in Budapest (51 mg/L total hardness as CaCO3, 40 mg/L alkalinity). In Budapest the total hardness would come from calcium as well as magnesium, leading to a different flavour outcome — competitors beware …

Recipe 3 – SCA

  • 40.1g Buffer
  • 68.6g Mg
  • 891.3g DI water

This is the official SCA specifications from the SCAA 2009 handbook. Similar to Budapest only the total hardness has gone up slightly. The specifications state a range of total hardness as low as 17 mg/L as CaCO3 up to 85 mg/L as CaCO3. So you could keep your buffer here constant at 40.1g and go as low as 17g of Mg solution or as high as 85g (don’t forget to subtract the total concentrates used from your DI water!).

Recipe 4 – Barista Hustle Water Recipe

  • 40.1g Buffer
  • 80.7g Mg
  • 879.2g DI water

The original Barista Hustle water recipe — where it all began. Add an extra 4.3g of the Mg concentrate and you’re at the top limit of the SCA specifications.

Recipe 5 – Rao Water

  • 50.1g Buffer
  • 75.7g Mg
  • 874.2g DI water

This is close to Scott Rao’s recommended water chemistry for brewing flavourful, balanced coffee. Slightly higher than the SCA in both total hardness and buffer, with a little more buffer than the BH recipe.

Recipe 6 – Hendon Water

  • 30.8g Buffer
  • 99.9g Mg
  • 869.3g

This is close to the centre of Christopher Hendon’s and Maxwell Colonna-Dashwood’s “Ideal Brew Zone”. If you’re inclined to “dial in” some water for a particular roast, this is a good starting point.

Recipe 7 – Pretty Hard

  • 35.1g Buffer
  • 126.1g Mg
  • 838.9g DI water

This begins the ascent up in water “hardness”, probably better suited to espresso, or at least short brew times for filter. This is starting to grab a lot out from the coffee so brew recipes would need some adaptation. This rips everything out from the coffee. So either slow down or speed up the brew time via grind adjustments, and shorten or increase your beverage weight. Dependent on the roast somewhere along those two spectrums you’ll find something tasty. Or not.

Recipe 8 – Hard dot AF

  • 45.2g Buffer
  • 176.8g Mg
  • 778g DI water

This is a fairly high point with pushing mineral level where you’re basically cranking the amp up to 11. Your brew parameters from the earlier water recipes would need to change a lot here.


A Note about TDS

Note that the TDS given by this calculator might not be exactly the same as the TDS you would see if you measure the resulting solution with a TDS meter. This is because TDS meters assume a certain ratio of all the ions in the water, and by adding these solutions, we’re messing with that ratio.

¹ The “.7H2O” part refers to the fact that water forms an intrinsic part of the crystal form of this salt that you can buy in the shops, which is the clear crystals called Epsom Salts. Each magnesium sulphate molecule is surrounded by seven water molecules in this type of crystal. We’re specifying this here, as the weight of the water in the crystal affects the calculations.

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  1. tim.scongack

    This article is great thank for you putting this together, as someone new to this I had a few questions:

    For the above Budapest WOC mix do you mix the hardness and buffer solutions or the buffer and epsom salts?

    Once the concentrates are made how many ml do you add to 1 gallons; should you target 150 PPM?

    After creating the buffer solution I had to add more baking soda to get the PPM to 1000; are store bought TDS detectors accurate or should I stick to the concentrations outline above?

  2. robin.carey

    Would scaling these recipes up to multiple liters/gallons be as simple as multiplying the buffer, magnesium, and DI water up to your desired total? Or do the amounts need to be adjusted further for larger quantities of water?

    • BHLearn

      Hey Robin, for sure these recipes scale up and down. Just note that we don’t advise you leave very large quantities of water sitting around in storage for reasons of hygiene.

  3. jamie-2902

    Is it possible to make the hardness solution using calcium sulfate (gypsum) in place of the epsom salt. If so, how many g/L?

    • BHLearn

      Hi Jamie, In cases where you have corrosive water that is very soft, working with Gypsum might help to create a slightly positive LSI index. But there is a major risk of causing too much limescale buildup with this approach so you need to proceed with caution. To get at better understanding of working with LSI, we go into detail about it in the Water Course. We also recommend the Water Geek app for android. https://www.baristahustle.com/education-products/single-course-sales/course-the-water-course/

  4. Leonardy Huang

    Hi, thanks for the recipes!

    Quick question, do I need to shake the solution to make sure it is mixed properly, or can I just wait to let it dissolve by itself? Thanks.

    • BHLearn

      Hi Leonardy, Epsom salts and bicarb of soda are readily soluble in water but it’ll speed up the process to give your concentrates a shake when you are preparing them for sure.

  5. imagin4ry

    can any one help me how to measure the kh and gh of existing bottle water/tap water?

  6. fel.blake

    Hey BH, just wandering what”the book” is? It’s referred to in the original post under the “method” section. I’d like to read further about this. Super interesting stuff!

    • fel.blake

      Also, can I keep the “buffer”, “hardness” and a bottle of the BH mixed water in the fridge for any length of time? Or should it always be done fresh everyday.

      • BHLearn

        What about the freezer? You could dose what you need into a little ice tray and add a cube as and when you require.

  7. chris

    Hey, i have a knot in head.
    What should be the final ppm of the crafted water?

    • BHLearn

      Hi Chris – don’t try to measure the ppm with a conductivity meter. These assume a normal ratio of ions in (tap) water, and won’t give you an accurate reading for this recipe.

  8. Buster

    Quick question. Baking soda is made up of sodium and bicarbonate at 27% sodium the rest bicarbonate. So if we have 50g of the buffer in 1 L of water isn’t it only 36.5ppm of bicarb and 13.5ppm of sodium. Is this correct thinking? This also applies to the epsum salt also.

  9. Scott Manley

    Hi Gordon – Deionized water by definition has a pH of near 7 at 25C (77F) initially. When it comes into contact with the atmosphere it will absorb C02 and form carbonic acid, which will lower the pH. It sounds like you are using either distilled water; or RO water that naturally has low pH. Note that measuring pH can be tricky and is highly temporal. Also, the neutrality point of 7 is only true at 25C/77F. Meaning that as water temperature changes, so does the neutrality point. For example, the neutrality point of water at 200F is 6.14 pH. So at 200F, a pH of 6.14 would not be acidic.

  10. Joe

    Hi Ghazi,
    Did you find an answer to this question, was wanting to do the same thing.

    • ghazi

      Hi Joe

      You first need to find out the form of the mineral. For potassium bicarbonate , manufactures never state, after talking with a lot of people it seems that it is crystaline and natural no added water so “anhydrous” . There is maths included in another BH post –https://www.baristahustle.com/blog/what-can-we-use-to-remineralise-water/
      this nice post will tell you how much to add to 1 ltr DI water for your conecntrate. I have found with the maths included:
      100.115 divided by 50,000 x 1000 = 2g per litre

      Hope this helps


  11. Chris S.

    I’ve begun crafting water for espresso using the above as a guide and, so far, I’m pleased with the results. It truly is amazing how great an impact the water chemistry has on the extraction!

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