Helles Water Profile

[Garrete]

I will be making Jamil's Munich Helles and need to use r.o. water, mine is not good for lagers.

What would be a good water build to use? Also, do I need to build up the sparge water as well?

Thank you in advance.

[ajdelange]

Munich Helles is obviously brewed with decarbonated water so I'd be tempted to go with straight RO plus maybe 5% tap water to get trace minerals and perhaps a half teaspoon of calcium chloride plus a percent or 2 sauermalz in the grain bill.