Does mash acidity determine final beer acidity?

[Gustatorian]

And is there a way to predict final acidity in beer based on Mash pH, pre-fermented wort pH readings?

For example, if my Mash pH was 5.2, should I expect a lower pH in my final beer?

I ask this because I read a recommendation stating West Coast IPAs need a final pH of 4.5 or less. The acidity brightens/crispens the beer and accentuates the bitterness.

 

[mabrungard]

There is some linkage between mashing pH and beer pH, but it is the yeast that determine the beer pH. So being a tenth lower on your mash pH may or may not result in a similar reduction in the beer pH.

 

[beerbeer95648]

And is there a way to predict final acidity in beer based on Mash pH, pre-fermented wort pH readings?

For example, if my Mash pH was 5.2, should I expect a lower pH in my final beer?

I ask this because I read a recommendation stating West Coast IPAs need a final pH of 4.5 or less. The acidity brightens/crispens the beer and accentuates the bitterness.

Yes and no.... Like Martin said, it is the yeast that determines final pH. But if you get to know your yeast, you can make an educated guess of the final pH based on pre-fermentation numbers (more so than mash pH numbers). My house strain is WLP007. I find about a .7 pH reduction through fermentation. I acidify at the start of boil to the 5.1-5.2 range, knowing that the pH will drop during the boil, I am hoping to not have to re-adjust at the end of the boil. I do however routinely acidify my wort at the end of the boil if needed to hit my personal target of 4.9. I like most of my beers in the 4.2 pH range post fermentation, and unless I hit the 4.9-5.0 range post boil I dont get it with WLP007 at least...When I brew Saisons I target the same post boil numbers but get closer to a 1.0 pH drop.

 

[andrewmaixner]

pH is logarithmic. a difference of 0.5 between 5.2 vs 5.7 would be less than 0.05 once the beer gets down to the standard beer level of low 4.x range for non-soured beers.

 

[Gustatorian]

Yes and no.... Like Martin said, it is the yeast that determines final pH. But if you get to know your yeast, you can make an educated guess of the final pH based on pre-fermentation numbers (more so than mash pH numbers). My house strain is WLP007. I find about a .7 pH reduction through fermentation. I acidify at the start of boil to the 5.1-5.2 range, knowing that the pH will drop during the boil, I am hoping to not have to re-adjust at the end of the boil. I do however routinely acidify my wort at the end of the boil if needed to hit my personal target of 4.9. I like most of my beers in the 4.2 pH range post fermentation, and unless I hit the 4.9-5.0 range post boil I dont get it with WLP007 at least...When I brew Saisons I target the same post boil numbers but get closer to a 1.0 pH drop.

Can you elaborate on why you like your beers at 4.2? Is this for all styles? What specifically are you tasting at 4.2 that you don't get at a higher pH?

 

[beerbeer95648]

Can you elaborate on why you like your beers at 4.2? Is this for all styles? What specifically are you tasting at 4.2 that you don't get at a higher pH?

I like a slightly brighter finish and how acid helps to reduce perceive sweetness. Winemakers do this all the time, they use organic acids to cut residual sweetness in wine. I was always struggling to get that slightly bright citrus cleanliness in the back of some of my hoppier beers. Dropping my pH solved that. With some of my darker beers I tend to let the pH ride a touch higher. But for anything light and drinkable I prefer 4.2 as my target final pH.