[Brew.Drink.Repeat.]

A buddy and I are brewing our first Czech Dark Lager tomorrow morning. We're starting with RO water, so we can build it however we need to.

I know the general idea for most lagers is to keep the water soft / low-mineral as much as possible. I'm also under the impression that as a general rule we probably want to have at least 30 - 50ppm of calcium for fermentation purposes, and around 30ppm of chloride as a flavor baseline. (We brew no-sparge BIAB, so all the salts will be added to the full amount of mash water prior to dough-in.)

Where I am right now is 46ppm calcium, 13ppm sulfate, and 34ppm chloride, with a predicted 5.4 mash pH.

Does this sound like a reasonable starting point for the first attempt?

I should mention that, if I'm going to err one way or the other, I will always prefer my beers to be drier/sharper rather than more "rounded".

Thanks in advance for any guidance!

[denny]

I have no idea where the concept of low mineral water for lagers comes from. That is not universally as true as it's made out to be.  Anyway, I'd use the brown full (or is it called malty?) profile in Brunwater.

[BrewBama]

I have no idea where the concept of low mineral water for lagers comes from. That is not universally as true as it's made out to be.  Anyway, I'd use the brown full (or is it called malty?) profile in Brunwater.

Probably from the Characteristic Ingredients comment in the BJCP: “Pilsner and dark caramel malts with the addition of debittered roasted malts are most common, but additions of Vienna or Munich malt are also appropriate. Low mineral content water, Saazer-type hops, Czech lager yeast. Any fruity esters are typically from malt, not yeast.”

This is what I’d do: (I use a full volume mash, no sparge.)

[Brew.Drink.Repeat.]

Thanks guys...

@denny: I suspect it came from the Pilsen profile (which I know we're not supposed to pay much attention to the city water profiles, but it seems that -- at least for lagers -- a lot of people do). The Brown Full profile is Ca50 / Mg 5 / Na 27 / SO4 50 / Cl 60

@BrewBama: with no sulfate at all, how does the bitterness present? The style obviously isn't high-IBU, but I want to be sure it's perceptible in the finished beer. (We're also adding some Saaz in the whirlpool and dry-hopping to get some extra Saaz-y-ness. That's probably not a word, but it is now LOL!)

In the end, I just want to make sure the malt profile isn't too big or too "round"

[BrewBama]

I’ve never been to Pilsen so I don’t have first hand experience. However, everything I read says “Medium to medium-full body, considerable mouthfeel without being heavy or cloying. Moderately creamy in texture. Smooth.”  They even go so far as to recommend debittered roast malt to reduce sharp flavors. That description doesn’t point me to a hoppy, sharp beer.

 …but if you want a sharper finish then by all means I think you should add some gypsum and/or Epsom salt.

[Brew.Drink.Repeat.]

To be clear, I don't want a sharp or bitter beer. But it's that heavy / cloying thing I'm definitely wanting to avoid! 

[Brew.Drink.Repeat.]

Here's what we decided to go with, which is basically Brown Full with a bit less sulfate than called for:

Ca 50 | Na 2) | SO4 30 | Cl 60 | SO4:Cl 0.5 | pH 5.41

Thanks for the input, I'll let you know in a few weeks how it turned out, and what we might change for next time!