Beersmith pH articles....and the correct pH range

I read in Beersmith articles the correct pH measurement range is 5.2 to 5.6. But, these articles and others rarely say whether that is at room temp or mash temp and it makes the topic very confusing.....for me anyway.

Especially, after I also read this from Jonathon Palmer's How To Brew page 158:

"Let me state the goal right up front, for best results the mash pH should be 5.1 to 5.5, when measured at mash temperature, and 5.4 to 5.8 when measured at room temperature."

So, what is the 5.2 to 5.6 in all the Beersmith articles? Sounds to me must be at mash temp. And what about the magical 5.2 a lot people talk about, is that at mash temp, and therefore 5.5 at room temp? If not, it is out or range.

The big issue for me is if people (inc. me) are aiming for 5.2 at room temp, that is 4.9 at mash temp and too low, out of range.

Let me first state for clarity:  Any reference to a pH measurement is ALWAYS, always, always, at 20C unless otherwise stated.  Thus, in any scientific papers the reader never has to guess what the conditions are at which the pH is measured.  In general, the offset of pH from mash temperatures to room temperatures are as Palmer has stated in his book.  Many things can slightly change this relationship, including but not limited to ions and salts in the mash and their concentration.  This is also affected by the contribution of minerals, starches, sugars, proteins, and other ion contributions from the malt.

Narziss published most of the basic relationship between temperature, pH (at room temperature), and enzyme activity of all the major enzymes of concern to the brewer which results in the chart I have attached below.  Mind you that the ranges listed are an optimum for performance and not a limit of performance for each enzyme.  Remember these same enzymes help barley seed germinate and grow, utilizing the energy stored in the starches, at typical ambient temperatures!  It is a matter of rate and not of ability.

As brewers, we should be cognizant of the pH ranges and target the mash pH based upon what we expect to accomplish with our wort.  Being outside these 'ideal' ranges is not a deal breaker for mashing:  Malted barley wants to become wort!  It is more an aspect of efficiency.

Another good description of the specific enzymes and activity ranges can be found on the AHA site at https://www.homebrewersassociation.org/how-to-brew/enzymes-in-beer-whats-happening-in-the-mash/

Thanks for the clarification on the reports from Beersmith articles.

It seems we have a difference in opinion then, Palmer says 5.4 to 5.8, Beersmith (and I think a lot of other articles), 5.2 to 5.6.

I wonder why Palmer has a different range?! It confused me no end!!

As you look at the 2 main enzymes: alpha-amylase and beta-amylase, you see not only the optima box, but also the shading around showing the range of activity.  The interpretation of 'optimum' range versus 'effectiveness' range has a lot to do with the minor difference in opinions between most of the literature and Palmer's recommendation.  This is also influenced by the choice between higher fermentability versus higher body, which tends to hang on the beta amylase activity -- more active at the lower end of the pH range.  If you look over the chart from Braukaiser that I attached, you will see his recommendation of 5.3 to 5.6 as being 'optimal mash pH target'.  In my experience, the effect between 5.2 and 5.6 in the mash leaves a relatively minor difference in the wort.  I'm sure that there may be others who have seen/experienced a stronger differential in wort quality, but it is beyond my meager means to discern it either in wort performance or beer flavor.

In the end, I don't really worry too much about it as long as I am somewhere within the range of 5.2 to 5.6 for most of my recipes.  Maybe someday when I get the rest of my process so buttoned down that I can see a difference in a couple of tenths of pH, I may revisit my pH targets.  For right now, I make beer and by most measures it is good.