Inadvertent Water Experiment

Random thoughts:

- Did you use any acid or acidulated malt? If not, a typical pilsner grain bill in RO water would have a fairly high pH. But if you got your normal mash efficiency, I wouldn't worry too much.

- Was your wort a little darker than normal after the boil by any chance?

- Ideally, you want some calcium for yeast flocculation. But between the trace Ca in your RO water and the Ca that's already in the malt, I suspect there will be enough in your wort to get the job done. But maybe a bit slowly.

- I'd consider adding some CaCl2 to the finished beer to get some Cl into it for flavor.

ETA: I almost forgot the most important part. When this beer is done, please report back that it's the best beer you've ever made, so that people can take it as incontrovertible internet proof that mash pH and mineral levels are irrelevant!

 

In addition to Vikeman's comments, I'll add that hop utilization is rather dependent on the pH of the boil, which was likely higher then usual this time around. A higher pH will result in more alpha acids being dissolved, so you may notice more bitterness in this batch.

 

I remember reading an article by Martin Brungard about low calcium being typical for lagers in southern Bavaria. Obviously that's not the same thing as Czechia, but anyway it might turn out okay.

 

Czech pilsner? You don't need no stinking salts. Seriously.

 

Beer advocates very own Marshall Schott!