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.
Nice! I love the idea of using low hardness tap water as a starting point, maybe with a carbon block to clean it up.
I’ve flipped the water calculator around so that you enter the target water and it tells you how much of each solution to add.
https://docs.google.com/spreadsheets/d/1mq7O5qAHtgtN3bnz2raASsQ7tM_c2JBB/edit#gid=2034820667
Thanks!
Hi BH. Thank you for updating the DIY water recipes.
If was to use Potassium Bicarbonate as the “buffer” would the 1.66g per litre of Distilled water still be the correct calculation for the concentrate?
Thanks
Ghazi
Hi Ghazi, We don’t have experience using potassium bicarbonate for remineralisation. You might try asking the Barista Hustle FB Group for some advice on this one: https://www.facebook.com/groups/baristahustle/
Thanks, I’ll get in touch with the group.
Thanks so much for this. One questions – ive been using the ‘barista hustle original’ water for filter v60 brews, and in general, ive been really happy with body/mouthfeel, acidity and balance in terms of taste, however I am struggling with getting much aroma (which i’ve gotten in the past from cafes with, say, natural process ethiopean beans). The aroma when i make coffee at home always seems subdued. For background regarding how i brew at home – I use lighter roast coffee from different well regarded specialty sydney & melbourne roasters, and gravitate towards natural ethiopian, brew about 23g… Read more »
What’s the best way to add the concentrates to the third glass container? Dealing with tenths of a gram seems to be difficult by just pouring from a separate 1L bottle. Thanks!
Hey Brandon. You can use a calibrated Pipette.
If you happen to have a calibrated pipette lying around I’d follow BH’s advice… but as for myself I’ll be using a little squeeze bottle ¯\_(ツ)_/¯
I’m using magnesium chloride, calcium chloride, and potassium bicarbonates and would like to know how can I have the same results using these minerals (specifically the mg and ca). For instance to have a total GH of 80 ppm, should I divide it to 40 mgcl and 40 cacl? How can I play with both of them to reach to the same results above?
Hi Mohammed, We don’t have experience with magnesium and calcium chloride. We usually use magnesium sulphate. What we can report is that most espresso machine manufacturers we speak to warn us against too many chlorides in brew water because they increase the conductivity of the water which can increase the possibility of corrosion. E.g. sea water is more conductive than fresh water.
Note there is no reference to the pH of the deionised water. I’m using water with a pH of 6, TDS of 10, almost zero of anything else. What assumption if any is made re pH of the deionised water, and what would you expect the pH of the resultant mix (in calc 1) might be? Thanks.
Just wondering because baking soda is supposed to breakdown beyond 50 ‘C in solid form, is this the same in aqueous form?
So I’ve been using these BH recipes since the original article and definitely have seen an improvement in my coffee versus my RO water brews. Just curious though, a few days after I’ve made my concentrates, some sort of salts start to precipitate out of my water and settle at the bottom of the container. Stirring/shaking doesn’t redissolve them either. I’ve tried making the solution at different total volumes, storing at room temp and refrigerated, and I get the same results every time. I’m no chemist, but some sort of reaction is occurring. Any thoughts or suggestions??
It sounds like you might not be using distilled water for the concentrates. If you’re using a water that has some calcium in it already, then it isn’t surprising that you’ll see some scale forming.
I’ve had the same problem, even using distilled water.
I’m using RO water and usually measuring about 5ppm TDS. I wouldn’t think that would be enough to affect anything. And I’m not talking about scale forming, it’s more like large salt crystals that form back in the jar I store my concentrate in. Any other ideas?
Hi! I would like to ask how long I could keep the solutions/concentrates for? Do they need a cool environment? Thank you
Hey Geoly, the concentrates won’t keep indefinitely because they don’t contain any antibacterial material but refrigerated, will be fine for a couple of weeks. This assumes you will boil them after adding them to your brew water. One cool approach is to add the amounts you need into ice trays and add the ice cubes in the appropriate amounts to your kettle as and when you need them.
Wow!! That’s a great idea with the ice cubes! Thank you very much!
Hello, I was wondering instead of making the concentrates can I just weigh out the magnesium and sodium bicarbonate in milligrams then add that to distilled water? If so how many mg per liter would I need to add to get the same results at the barista hustle recipe? Thanks
It’s theoretically possible, but hard to weigh out such small quantities accurately enough, which is why we use concentrates. A typical sub-$100 milligram scale isn’t very accurate for small amounts – you’ll need a proper lab scale for that.
That said, here’s an example to get you started: 2.46g/L of Epsom salts makes 1000ppm of hardness in our concentrate, so to get 100ppm hardness, you could dissolve 246mg directly into your 1L brewing water.
Hello, I was wondering how you would calculate the mixtures with these kind of solutions that equate to roughly 1000ppm but still use the recipes listed in the 2017 article on DIY Water Recipes. The 2017 solutions do not equate to 1000ppm so it is not a direct translation to the new way of mixing them in this 2019 article.
We’ve recalculated the previous recipes for the new concentrates and added them in to this article – hope that helps! Tom
In the water problem, I prefer to use Mineralise Pre-existing Water, which makes the water formula simpler by simple mathematical calculations, especially for the contestants. (But the cost will be higher than the first method. Deionized water usually has a retail price of about 2AUD/5L in mainland China) In my hometown, the “NingXia” in the northwestern province of China is usually 200-600 PPM, and the water’s alkalinity and pH are also very high. (Compared to Melbourne 20-40PPM, this is the difference between heaven and hell.) Usually the water hardness in these areas is extremely high, and the kettle will… Read more »
I still have a few questions. If you add the calcium and magnesium ion concentrate directly in deionized water (pH=7) without adding sodium bicarbonate, will this make the taste of the coffee worse? The second question is about KH = 40 mg/L. This is the standard required by SAC, but why is it 40? What is the basis here?
Thanks to the magical BH team, I and many Chinese baristas want to know what this is.
If you don’t have any buffer, the coffee is likely to be too acidic and harsh for most palates. Tweaking the amount of buffer will change the perceived acidity of the coffee and bring out or mute certain flavours. Experiment and see what works best for your roast style and personal taste! Regarding the SCA’s recommendation, this is a fairly typical amount of buffer in soft water, of the sort usually preferred for brewing. These recommendations were implemented before many people were using mineral concentrates, so are perhaps based on what was achievable using typical water filters, rather than a… Read more »
THanks!~ 🙂