Glad to help! Thanks as always Martin for chiming in.
mmitchem, i think you are indeed starting to wrap your head around it.
If you want, feel free to personal message me the water profile’s your creating as a sanity check… not saying I know everything but with Martin’s help Ive been turning out good beers of all different styles and think I have a decent grasp on things.
Here’s something I should know, but for some reason I find it confusing:
If I take a sample of my mash and cool it down to 60 or 70 F and then take a pH reading which shows 5.4, is that the number I am generally looking for or do I need to correct it for the mash temperature? If so, what is the correction factor?
I understand that the same mash will read completely different pH figures depending on the temperature, but I wonder if mash pH number needs to be corrected to the 148 to 156 range. Or maybe the pH is exactly the same and I need a meter that corrects automatically.
When I asked pretty much the same thing, the answer is that pH is read at room temp. So, 5.4 at room temp is what you’re looking for. Unless of course I totally misunderstood…
To make matters worse Gordon Strong says to measure it at mash temperature in Brewing Better Beer. :-\ But I am a convert in the Water Church of Martin so I use room temperature… 
[Edit]
It seems there’s conflicting info in his book. Page 34 states:
[quote]The mash pH should be in the 5.2 to 5.5 range with a target of about 5.3. Note that the mash pH is measured at mash temperatures, not cooled.
[/quote]
But on page 140 he states:
[quote]…adapt a common system, typically measuring at warm room temperature (25C, 77F), using a pH meter with ATC, or by keeping a temperature compensation table handy.
[/quote]
Thats a confusing one to me as well…Ive always measured at room temp and corrected .2 ish lower to get my mash temp since that makes sense to me…if the pH is working at a certain temp then thats whats actually going on in there.
So if I read 5.6 on my pH meter, then Im assuming my pH at sach temps is about 5.4.
This is what I do, and I remember the correction to be 2.5 to 3 ish.
In my case I think that I would be better off using Distilled Water…even with alot of crystal malts, the pH gets pretty high with the RA in my water (303ppm)…
For instance I am brewing a Doppelbock this weekend doing a big triple decoction. Here is my recipe I have come up with after reading the Classic Styles Series for a 6 gallon batch…
OG 1.078
IBU 25ish
SRM 24ish
14lbs Munich I (7SRM)
2lbs Bohemian Pilsner (1.7SRM)
8oz Caramunich I (39SRM)
8oz Caramunich II (57SRM)
2.25 Mittelfruh @ 60mins (4.1%AA)
.35oz Mittelfruh @ 30mins (4.1%AA)
120 Boil
Using distilled water for a 6.15 gallon mash (1.4 quarts/lb)
I am making the following mash additions:
2.5g Gypsum
2.5g Calcium Chloride
1.8g Chalk
That gives me 85ppm Calcium, 59ppm Sulfate, 51ppm Chloride, 106 Bicarbonate, RA of 27 annnnnnnd a mash pH of 5.4. That puts me in the ballpark because I am not using heaps of crystal malt that lower the pH of the mash.
Sound about right???
Not heaps in your recipe, but CaraMunich is a crystal malt, make sure you take that into account.
I could even use something like 1.2g of gypsum, 1.2g CaCl2 and 2.5g Chalk to get a little more towards that room temp pH of 5.6, or mash pH of 5.3-5.4
Y’all know what I mean
Yeah man, all was accounted for when I calculated the Mash Acidification. You are right, only a pound of crystal and like 16lbs of base malt…Doesnt acidify the mash a whole lot…
Sounds like you are getting a handle on it.
For a beer like this having a mash pH around 5.5 would not be a bad thing.
If I am getting it - it is only because awesome folks like yourself have taken the time to line me out, and it is greatly appreciated 
With that being said - if I were going to aim for a pH of 5.5 at mash temp, it would be safe to go for around 5.7 at room temp?
That’s about right. 5.4 at room temperature is somewhere around 5.2 at mash temperature. Since that offset is relatively consistent, it makes little sense to damage your pH probe by dunking it in hot wort. In fact the convention of citing mash pH at room temperature is specifically called out in DeClerck’s, A Textbook of Brewing. I’ll have to disagree with Gordon on this issue. This is the reason that Bru’n Water mentions ‘room-temperature measurement’ when ever mash pH is discussed or presented.
Using a shot glass that I’ve pre-chilled, it only takes about a tablespoon of wort to fill the glass sufficiently to submerge a normal pH probe. That small amount of wort cools down in a minute in that glass. I suppose you would have to use a larger glass if you have one of those meters with the larger probe end.
No! The safe range of room-temperature mash pH is about 5.3 to 5.5. That indicates that the pH in the mash is 0.2 to 0.3 units lower, but that doesn’t really matter. The only thing we need to focus on is the ‘room-temperature measurements’.
A 5.4 room-temperature pH is a good all-around target. If you want your beer a little sharper or tarter, aim a little lower (5.2 to 5.3). If you want your dark beers to be a little softer, aim for 5.5. But don’t get carried away with a high pH target. All kinds of things go wrong when you exceed about 5.7 to 5.8. You can be a little low with pH and the beer should taste OK. But it won’t be so good if its a little high.
That’s concise. I was starting to get even more confused for a second there. I may have to print this and put it in my brewers log.
That’s right - NO with exclamation lol.
Roger that - go for the room pH.
Times like these I am thankful that folks like Martin have made such great and useful software available to us. If you find it to be useful, I think donations are the right way to tell him you want more of the same. Thank you all for helping me get some really good prnciples down for building up good brewing water profiles. But more than that - helping me understand what I am looking for in water to make it appropriate for what I am brewing. That sort of knowledge is priceless.
Now I hope I whip up on all of you next NHC haha 
Wow… reading this thread all the way through and understanding what Martin explained reminded me of a commercial where Charlie Daniels hands a ripped up violin back to the waiter saying " and that’s how it’s done son ".
Haha, I remember that commercial, think it was Geico or something. Either way, these guys have laid it out for the world, and probably not for the first time either
Just solid information that has definitely helped me get a grip on the importance of brewing water, especially pH…
That is good to know. Thanks for the clear explaination.