Originally Posted by Cranny04
I'm going to build my water from RO. Wild brews has Flanders water as:
Ca - 114
Mg - 10
Na - 125
S04 - 145
Cl - 139
HCO3 - 370
I've been following the Brewing Water Chemistry Primer sticky. Using the Calculator on Brewers Friend. I've come up with using 2% Acid Malt in the grist and for 18 Gallons of water using 16 grams of Gypsum and 18 grams of Calcium Chloride.
Provided that you add only the gypsum, calcium chloride and sauermalz you should be OK though I would recommend doing it the first time w/o the gypsum. I don't recall any high sulfate qualities in Flanders Red but I could be remembering wrong. If you brew it sans sulfate you may prefer it even though the water traditionally used for it does contain some sulfate. Once it is brewed without taste with and without a small gypsum addition in the glass. If it tastes better with the sulfate then use that in the next brew.
Note that just adding calcium chloride (and gypsum) to RO water will not give you either the bicarbonate or sodium in the profile you have posted. But you would not want those anyway.