Can someone check my water work?

[BigJefe]

I live in San Diego and I am planning on brewing a Dry Irish Stout this weekend (in time for St. Patrick's day), and I have been messing around with the various water chemistry sheets and I believe I have a decent recipe.

First off here are the SD and Dublin Profiles:

(ppm) San Diego (Otay) Dublin
Ca 47.2 115
Mg 27.1 4
Na 107 12
Cl 140 19
SO4 124 55
Alkalinity 135 ?

Chloride/Sulfate Ratio 1.13 0.35

Obviously, with the exception of Calcium, everything is WAY too high, when trying to mimic the Dublin style, so I've decided on a 50% dilution (5Gal San Diego and 5Gal RO/Dist). Focusing on the all important Chloride/Sulfate ratio, I've decided to toss in 3g of Gypsum into the mash water and 5.9g into the sparge water.

Using -TH-'s EZ Water Adjustment spreadsheet I get a final profile that looks like this

(ppm) San Diego (Otay) Dublin
Ca 78 115
Mg 14 4
Na 54 12
Cl 70 19
SO4 196 55
Alkalinity 135 ?

Chloride/Sulfate Ratio 0.36 0.35

Obviously, I'm not nailing the profile, but it seems pretty damn close and with in the acceptable (Palmer) ranges. What I am happy with is the ratio being spot on. It looks like my mash pH is going to be 5.64 which is close enough to the 5.4 - 5.6 range, and to be honest I worry about learning the intricacies of pH for my next brew.

Anyone care to comment?

Thank you and Cheers,
Jeff

 

[ajdelange]

There are lots of ways to skin this cat but were I working with this water I would add 4 parts RO water and half to a full teaspoonful of calcium chloride. That should be all you need to do. This gets the alkalinity down to the point where mash pH may be a wee bit high but tolerable, calcium high enough for good yeast health, etc, sulfate low enough that the hops bitterness is nuanced and chloride high enough that the beer will be smooth and round.

This is how I do it (following Ashton Lewis's recipe) and it comes out very authentic - almost identical to Guiness. Served in the proper glass on nitrogen most people can't tell the difference.

 

[PoppinCaps]

I would second aj's advice (listen to him, he knows what he's talking about), and add a caveat about trying to hit a region's water profile. It's hard to tell what the brewery adds/dilutes in their brewing water, so you should try to formulate your water based on understanding of the minerals and how they affect your beer.

 

[BigJefe]

Would this be a teaspoon in the mash or in the whole 10 gallons in my HLT of 80/20 water?

 

[ajdelange]

In the whole volume. For 10 gal I'd use a 1.5 tsp with an 80/20 cut.