Mash pH - whats the big deal ?

After reading up on as much as I can find on the topic of brewing related ph I have ended up wondering if the benefit of hitting specific mash ph's isn't really just about getting a good efficiency.

I don't really care about efficiency at the homebrew scale since it only costs a dollar or two more to buy more grain if necessary. So, assuming I can manipulate many of the other variables such as attenuation/dextrin content with mash temperature, and being able to acidify sparge water and/or kettle wort using acid, what are the benefits of mashing at ph 5.2 versus 5.8. I really cant think of anything right now ?

Lets also take consistency out of the equation and say, for the sake of argument, that I start with RO water and add measured salts to get somewhere in the range I mention above, and lets just say I make the same water every time I brew a particular beer.

lots of assumptions I know, and I dont intend to actually take this approach, I just want to try and learn if there's some extra benefit I haven't taken into account with specific regard to mash ph alone. I have read many articles which list together the benefits of achieving 'optimum' mash/kettle/ferment/product stability ph. but not many just on mash ph alone.

Mash efficiency is the least of your concerns. If you have seen any of the hundreds of posts on this subject here you will have observed that flavor is what is of interest. If you were to brew 2 otherwise identical beers with one at mash pH 5.8 and one at 5.4 you would answer your question as soon as you tasted the beers. All the flavors are 'brighter' at 5.4.

craigevo said:

what are the benefits of mashing at ph 5.2 versus 5.8. I really cant think of anything right now ?

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Flavor.

ajdelange said:

Mash efficiency is the least of your concerns. If you have seen any of the hundreds of posts on this subject here you will have observed that flavor is what is of interest. If you were to brew 2 otherwise identical beers with one at mash pH 5.8 and one at 5.4 you would answer your question as soon as you tasted the beers. All the flavors are 'brighter'.

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Are the flavors brighter at 5.4 or 5.8?

5.4

I disagree that mash pH has much to do with efficiency. Mash pH has much more to do with conversion and fermentability. Efficiency is far more effected by the grind and the run off rate and procedures.

https://www.youtube.com/watch?v=zJj__jEkFUE&feature=youtube_gdata_player

John Palmer speaketh all ye seek.

AJ - this brightness you talk of, is it due to the mash ph, or perhaps due to the derived kettle/fermenter ph ? I guess i didn't design my question very well.

If I do two batches of the same grain bill.
1. mash at 5.8 and acidify the pre boil kettle wort to ph5.3
2. mash at 5.4 and acidify the pre boil kettle wort to ph5.3

I know everyone will now tell me that the differences in ph will result in a different wort fermentability and dextrin content, so I will run the two mashes at different temperatures to each other to compensate for the differing ph and result in the same fermentabilty and dextrin content (calculated using my time machine)

Brewing of beer involves hundreds or perhaps even thousands of biochemical reactions most of which are catalyzed by enzymes. An enzyme works best is a given temperature and pH range. There are lots or reactions going on in the mash tun beyond just those of the amylases. As even the two amylases have different optimum pH's it is probably clear that there is no optimum pH at which all the enzymes in play will work at their best. So we rely on empirical determination of what is a good pH at which to operate the mash tun. That seems to be about 5.4. Go higher and beer flavors become dull (and you probably get less conversion as well). Go lower and they say the beer tastes thin. So you must, for best flavor, get the mash pH into the right range. There are reasons for wanting the pH out of the kettle to be 5 - 5.3 and so some brewers monitor that and make adjustments with additional acid or salt to get into that range if the runoff isn't in that range automatically. Get the mash pH right and the kettle pH tends to be right too as does the fermenter pH and final beer pH. So mash pH is the pH we focus on.