Is my water better for dark beer? Carbonite vs Bicarbonate

I was under the impression that my water was more for darker beers as I was looking at the HCO3 being 147, but in the Wardlab info, they state that with the CO3 being 12, it is considered to be soft water? So is it Carbonate or Bicarbonate that makes it better for the mash of dark beer?

Sodium, Na 73
Potassium, K < 1
Calcium, Ca 1
Magnesium, Mg < 1
Total Hardness, CaCO3 3
Nitrate, NO3-N 0.3 (SAFE)
Sulfate, SO4-S < 1
Chloride, Cl 14
Carbonate, CO3 12
Bicarbonate, HCO3 147
Total Alkalinity, CaCO3 141

Is this water run through a water softener? There are basically no minerals in your water (Ca, Mg). The main point of water is your “effective hardness.” This takes into account the other minerals that are present in your water. Check out this chapter if you have not already - use the pdf chart at the end to plot your numbers. The problem I see is that if you add minerals like calcium and magnesium, it will potentially change your “effective hardness.” My water is hard - bicarbonate of 268, with fair amt of calcium and mg and other minerals. The water that goes through my water softener is still 268 on bicarbonate - but all of the other numbers are more in line with yours.

No softener, but it goes through a sediment filter. So is it CaCO3, CO3 or HCO3 that determines if you have water best suited for mashing dark beers?

No offense, but are you sure you don’t have a softener? It would be unique (in my experience) to have water with that much alkalinity and no Ca or Mg.

Anyway, what you want to look at as far as predicting mash pH is the residual alkalinity (RA). With moderate alkalinity and almost no hardness, your RA is ~140 ppm CaCO3 equivalent, or the same as the total alkalinity. In tap water (pH 7-10), almost all the alkalinity will come from HCO3.

With an RA of ~140 ppm CaCO3, your mash pH will come out in range for most amber-to-brown beers. You’ll probably still want to add >50 ppm Ca, plus sulfate and/or chloride for flavor reasons. And carbonates for darker beers.

yep, no softener. I do have a backflushing whole house filter that is comprised of 1/3 marble chips and 1/3 pyrolox (which is activated carbon) and 1/3 headspace. This filter removes hydrogen sulfide and/or iron bacteria(sulfur smelling water). But there is no ionization filter/softener.

thanks for the clarification on the RA though…I thought I understood this then recently got thrown by data!