[HopDen]

When making a dark lager, in this case a schwarzbier, what is the preferred water profile? Starting with RO. I am thinking that a soft water would work fine but I am not certain because of the dark grain additions.

[Bel Air Brewing]

When making a dark lager, in this case a schwarzbier, what is the preferred water profile? Starting with RO. I am thinking that a soft water would work fine but I am not certain because of the dark grain additions.

I recently brewed a Schwartzbier with my standard filtered city tap water.
It turned out very, very nice.

Here is the profile:

Ca = 39
CaCO3 = 96
Cl = 20
Na = 30
SO4 = 58
Total Hardness = 112

[erockrph]

I generally target the same mineral profile as I would for a pale lager. You might have different acid requirements based on how you handle your dark grain additions, but I just plug that into my water calculator. I only start thinking about bicarb additions in something like a stout or porter where roasted malt flavor is dominant, and I find that a bit of a higher pH makes for a better flavor in the finished beer.

[beersk]

You could also consider reserving the dark malt for the vorlauf step for smoothness. With RO water, I usually add a 1/2t each of gypsum and calcium chloride. And if I mash with the dark malts (midnight wheat) I use a little baking soda to make sure the pH is in a good range, maybe 1/4t or so for a 5 gallon batch with 5% midnight wheat. The added sodium will help with roundness and mouthfeel. But it's not necessary if you want to reserve the dark malt for after the mash.

[HopDen]

Thanks for the input folks! I think I will be matching my soft water profile but raising the mash pH a bit and adding the darker grains down stream sounds good to me.