Getting Started with Water Adjustment

In order to get the most out of my beers I am looking to playing with my water chemistry. Here are the numbers for my tap water:

Starting Water (ppm):
Ca: 26.7
Mg: 20.8
Na: 26.6
Cl: 53.9
SO4: 50.4
CaCO3: 84.5

Mash / Sparge Vol (gal): 2 / 2
Dilution Rate: 0%

RA (mash only): 53 (10 to 14 SRM)
Cl to SO4 (total water): 1.07 (Balanced)

Couple of questions:

1) The pH of my tap water is high (8.49), however upon reading I have discovered that it is not the pH of my tap water that matters. Am I correct? Also having just bought 5.2 Stabilizer is there anything else that it is good for or do I just put it down as a learning expense?

2)When doing the adjustments is it better to adjust only the mash or both the mash and sparge?

3)What are the most important things to be focused on when adjusting? Residual Alkalinity, Cl to SO4, individual minerals?

Thanks.

The good news is that your water doesn't need any drastic movements. It's very middle of the road.

The mash pH will be "about right" if your recipe yields a color of 10-14 SRM. If you intend to brew much lighter or much darker than that, you need to use salts that will help you move that SRM range. Typically it will be Chalk and Baking Soda to brew darker and Gypsum, Calcium Chloride, and Epsom Salt to go lighter (with varying effects on your Cl:SO4 ratio of course.

In most cases, mash-only additions are fine. Focus on putting the RA in range first, and see if you can do it without throwing anything off the charts. Your Cl level is the same as mine and I can tell you I've never had a use for CaCl additions. Gypsum will be your most used salt if you like hoppy beers.

sp, where in IL are you located? Maybe I'll get lucky and I can just piggyback off your report? Thanks.

Sadly, the report is not from IL. I am from Marengo, but right now I am away at college. The report is for Dayton, OH. Sorry.

So I am going to try this with my next beer, a RoggenBock. How does this look?

Starting Water (ppm):
Ca: 26.7
Mg: 20.8
Na: 26.6
Cl: 53.9
SO4: 50.4
CaCO3: 84.5

Mash / Sparge Vol (gal): 4 / 1.3
Dilution Rate: 0%

Adjustments (grams) Mash / Boil Kettle:
CaCO3: 3 / 0
CaSO4: 0 / 0
CaCl2: 1 / 0
MgSO4: 0 / 0
NaHCO3: 0 / 0
NaCl: 0 / 0
HCL Acid: 0 / 0
Lactic Acid: 0 / 0

Mash Water / Total water (ppm):
Ca: 124 / 100
Mg: 21 / 21
Na: 27 / 27
Cl: 86 / 78
SO4: 50 / 50
CaCO3: 203 / 174

RA (mash only): 102 (14 to 18 SRM)
Cl to SO4 (total water): 1.55 (Malty)