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
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.
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.
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.