Just wanted to share the recipe I have settled on after doing some at home testing with different recipes. I based mine on Lance's Light & Bright, but wanted some mag and sodium as well. This was preferred over the standard light & bright recipe, for me.

Add to one gallon of distilled water:

Calcium - 33 drops
Magnesium - 17 drops
Potassium - 33 drops
Sodium - 9 drops

homeburrero wrote:Beware that the hardness solutions of these concentrates are calcium chloride (CaCl2) and magnesium chloride (MgCl2). For every 10 ppm (as CaCO3) of hardness you are getting 7.1 mg/l of chloride ion. Even at low hardness levels of 20 - 50 ppm as CaCO3 you are looking at chloride levels in excess of what many espresso machine makers advise as the max permissible because of chloride corrosion risks.*

Maybe fine for pourover coffee, but for espresso machines, you're better off avoiding chloride. That's one reason that TWW's espresso formula contains no chloride.

Reviewing the specs for La Marzocco's recommended water formula, it recommends between 0.0 and 0.1ppm total chlorine in the water, but up to 30ppm of chloride.
If this is the case, how would you calculate out the max amount of MgCl2 that would be safe to add if trying to reach 80GH (the barista hustle recommendation)? And if you couldn't reach it with either CaCl2 or MgCl2, it seems like it may be safer using MgSO4 (epsom salt) as the hardness solution in my GS3.

EDIT:
It's been a long time since chemistry class, but here's a rough calculation. Someone correct me if I did it wrong.
Molar mass of MgCl2 (what's in lotus solution) is 95.211g/mol
Molar mass of MgSO4 (what's in epsom salt) is 120g/mol.
1 gram of commercially available epsom salt has 98.6g elemental magnesium in it.
Using the barista hustle water formula for 80GH, that's roughly 0.2g of epsom salt per liter of water.
This is roughly 20mg of elemental magnesium.
Divide this by the molar mass of Mg (24g/mol), multiply by the molar mass of Cl2 (70g/mol) and that's roughly 59mg/L of Cl2.

Assuming my math is correct, this is almost double the recommended limit of chloride to put into a LM machine. This is very disappointing..

maccompatible wrote:And if you couldn't reach it with either CaCl2 or MgCl2, it seems like it may be safer using MgSO4 (epsom salt) as the hardness solution in my GS3.

Yes. Note that the Lotus espresso formula limits the hardness to only 20 mg/L. As discussed above in this thread, Lotus is handy for water experimentation for pourover but in an espresso machine you're better off using Epsom if you want much hardness. The sulfate in Epsom is not desirable but has less corrosion risk than chloride.


Your calculations are on the right track. FWIW I'll add some comments inline:

It's been a long time since chemistry class, but here's a rough calculation. Someone correct me if I did it wrong.
Molar mass of MgCl2 (what's in lotus solution) is 95.211g/mol Yes
Molar mass of MgSO4 (what's in epsom salt) is 120g/mol. Correct for MgSO4, but be aware that Epsom is the heptahydrate with MgSO4*7H20, which has a molar mass of 246.5 g/mol
1 gram of commercially available epsom salt has 98.6g elemental magnesium in it. Typo. Clearly you meant 98.6 mg, which is correct for Epsom (the heptahydrate)
Using the barista hustle water formula for 80GH, that's roughly 0.2g of epsom salt per liter of water. Correct.
This is roughly 20mg of elemental magnesium. Correct
Divide this by the molar mass of Mg (24g/mol), multiply by the molar mass of Cl2 (70g/mol) and that's roughly 59mg/L of Cl2.Yes. Although I think it may be more straightforward to do the chemistry like this:
* 80 mg/L of divalent hardness as CaCO3 is always 0.8 mmol/L (simply divide by 100 to convert "mg/L as CaCO3" to mmol/L for any divalent salt like CaCl2, MgCl2, MgSO4, etc)
* Each MgCl2 molecule contains 2 chloride ions, so 0.8 mmol/L of MgCl2 contains 1.6 mmol/L of chloride ions. The molar mass of Cl is 35.5, and 1.6 * 35.5 = 56.8 mg/L Cl⁻ ion

Thanks homeburrero! I already have high levels of chloride 23! No need to add more.

Tried this the other day for the first time.


Simple and Sweet is a crowd-pleaser recipe that really works with any coffee you throw at it including Sey.


Light and Bright lives up to it's name but I actually didn't like it compared to my usual water which is also 60 ppm nor the simple and sweet recipe. Don't get me wrong, it's good, but it is more one-dimensional and not as balanced. I can see it shining well on really particular coffees but I wouldn't use this for daily brewing or even cupping unless I had another water profile to contrast.

I think the kit itself is nicely priced and perfect as a gift too. I love the freedom this kit gives you and how I can just add a few drops to my coffee itself.

My Lotus Water kit just arrived. I hope to use it to help me understand water recipes better, and my taste preferences against the beans I typically like. At some point I'll run low and probably have a good idea of the recipe I enjoy, and just batch it per typical home barista recommendations!