Note: This post has been updated! In July 2019 we wrote a follow up to this post, using a different set of concentrates to make it even easier to develop your own water recipes. Since having two different sets of instructions was getting confusing, we’ve changed the instructions in this post to bring them into line with each other, and to correct a slight error in the previous calculations. The new post includes an awesome online calculator to help you work out exactly how to remineralise your brew water.
Our Barista Hustle water recipe was and is a useful starting point for building water, giving you a good chance of success when brewing up coffee at home. For those willing to dive a little deeper, we can get far more specific.
The math can get rather complicated so we’ll spare the details until another time. The motivating factor here was to get the two variables (buffer and magnesium) into separate concentrates that are easily added to distilled water. This means you can create any brewing water with some combination of the two. Kind of like an etch-a-sketch for brewing water!
Here’s the recipe to get there:
Baking Soda – NaHCO3, Sodium Bicarbonate, Bicarb (not baking powder)
Epsom Salts – MgSO4, Magnesium Sulfate (don’t worry about “do not eat” labelling. We’re working with miniscule amounts, diluted 1000x, and boiling the water afterwards.)
Deionised/Distilled/Ultra-pure water (don’t worry about “not for drinking” label. This is to prevent people drinking too much ultra pure water. We’re adding minerals though, so it’s ok)
All ingredients are readily available from most supermarkets etc, and are super cheap.
Scales (accurate to 0.01g)
3 x ~1L water containers (preferably glass, and odour/residue free)
- Dissolve 1.68g baking soda in 1L of deionised water — this is your “buffer” concentrate, or “alkalinity”. Label and set aside.
- Dissolve 2.45g Epsom salts in another 1L of deionised water — this is your “Magnesium” concentrate, or “total hardness”. Label and set aside.
It’s important to note here also these recipes use magnesium as the source for total hardness; not calcium. This method only requires ingredients easily obtained from any supermarket. This is entry level stuff. You can mess about with calcium, sulphates, chlorides, and pH control when you graduate from here. Alternatively we’d encourage you to buy the book.
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
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.
Where to from here?
We’ve designed these concentrates to be super easy to experiment with. You don’t have to stick to our recipes!
To make your own, you only need to know two things.
- The concentrates are made so that 1g of concentrate equals 1ppm of GH (for the magnesium solution), or KH (for the bicarbonate solution), after dilution in 1L of water.
- Subtract your total concentrate weight (in grams) from 1000 and that’s how much water you need to dilute them with.
If your buffer amount used was 30g, and your Mg amount was 60g (90g total), you would be adding this to 910g of distilled water (1000g minus 90g). You’ll get the hang of it by reading the recipes above. This would give you a KH of 30ppm and a GH of 60ppm.
Let us know how you go in the comments below!