Simple mash ph question

[mhot55]

Everything I read has stated adding acid to water at room temp to get the desired ph (also salt additions based on your grist- roasted malts, etc). However, it is known that as the water temp rises the ph changes also. So my question is.....if I am shooting for a mash ph of 5.4, am I using ph of 5.4 at room temp or 5.4 at my mash temp (at say 150*)???? Also- the water Chemistry software out there (brewers friend, bru'n water), does it factor in the mash temp or not (if the answer is mash temp ph)?

I guess that's 2 questions

 

[ajdelange]

Everything I read has stated adding acid to water at room temp to get the desired ph (also salt additions based on your grist- roasted malts, etc). However, it is known that as the water temp rises the ph changes also. So my question is.....if I am shooting for a mash ph of 5.4, am I using ph of 5.4 at room temp or 5.4 at my mash temp (at say 150*)????

There is lots of debate about this. Most books, articles and the literature speak of laboratory (room) temperature pH but that is not universally the case. Most do not say anything specific on the subject. DeClerck specifically states that all references in his book are to lab temperature. Gordon Strong says specifically that he is talking about mash temperature pH.

Given that you can probably safely assume that pH refers to room temperature 5.4 is getting bit low as that will translate to, typically, 5.2 at mash temp.

Also- the water Chemistry software out there (brewers friend, bru'n water), does it factor in the mash temp or not (if the answer is mash temp ph)?

No, they can't. They would have to know the temperature glide (as I call it) for each malt specified to them. It wasn't recognized until recently that different malts have appreciably different glides.