17 replies to this topic

[Big Nake]

I suppose this is an extension of THIS thread and also THIS thread. Is there any useful information in taking finished beer and measuring the pH of it? I just measured the pH of 7 beers... some of them mine, some commercial. Maybe I'm bored and maybe I have a thing for pH and maybe, just maybe I have broken my brain from all this talk. You know that picture in Papazian's book for the chapter about all-grain? The one with the guy facepalming himself? That's me right now. Okay, here's what I have:Pilsner made with 830 (srm 5) 4.3MLPA (srm 10) 4.3Willamette Pale Ale (srm 7) 4.3Red Lager (srm 13) 4.4ESB (srm 11) 4.3Pacifico from MX (srm 3) 4.0Stiegl from Austria (srm 4) 4.1It's not really the darker beers I'm concerned about because those come out nicely for me. I'm really looking at the pale beers. My pilsner has a finished pH of 4.3 and I'll be honest... it's not that great. It's drinkable but something is not quite right. The pH of the other wimpy gold lagers is lower. I also have some Kona Longboard Lager, some Miller Lite and Coors Light in the bar fridge. I don't want to MAKE these beers but the question is whether the finished beer pH can tell us something about how our pale lagers or ales should be. Also, that pilsner I made on Friday with ALL of that acid... my guess is that the pH of that beer is going to be lower. Maybe too low. Thoughts anyone?

Edited by KenLenard, 09 March 2014 - 12:14 PM.

[neddles]

I don't have much to add but here are a few links worth browsing through. If not pH, what else could be holding back your pilsner?

 

httpss://www.homebrewersassociation.org/forum/index.php?topic=4875.0

 

https://www.weyerman...ash-pH_2010.pdf

[Dave McG]

I don't know what effect pH would have in the beer, but the scientist in me wants to know the conditions that you tested under. Specifically, what was the temperature of the beer when you read it, and was it carbonated or degassed. Both temp changes and carbonation level can have a real effect on pH. Because you can't control carbonation levels of commercial bottled beer, I would degas all samples and pick a fixed temperature to use as your standard for measurement.

 

Maybe you did do this, but without knowing anything about the beer, I would expect a cold, carbonated sample just out of the fridge would have a lower pH than warm and flat drawn from a carboy in your beer bunker.

[MyaCullen]

I don't know what effect pH would have in the beer, but the scientist in me wants to know the conditions that you tested under. Specifically, what was the temperature of the beer when you read it, and was it carbonated or degassed. Both temp changes and carbonation level can have a real effect on pH. Because you can't control carbonation levels of commercial bottled beer, I would degas all samples and pick a fixed temperature to use as your standard for measurement.

 

Maybe you did do this, but without knowing anything about the beer, I would expect a cold, carbonated sample just out of the fridge would have a lower pH than warm and flat drawn from a carboy in your beer bunker.

carbonic acid in the colder beer lowering the pH?

[MyaCullen]

I wonder if upping your carbonation level in your Pilsner would help Ken?

[Big Nake]

All of these beers were cool-cold (40s) and carbed. I thought about all of that but wasn't sure what the affects would be (if any) so I figured I would take them all under the same conditions. I could take a few of these, pour a sample and leave the glasses out overnight so the temp would rise and presumably the beer would go flat... but I wondered if letting it sit like that would have some OTHER affect on the beer's pH that would throw the measurement out of whack.

[Dave McG]

I'm working under the assumption that carbonic acid is a major player here. I don't know much about what other acids are present or their quantity. If Pacifico is sold with, say, 3.25 volumes of CO2, and you have MLPA at 2.5, then you have a significant change in h+ ions right there. Solubility changes with temp also, which is the reason we need to measure mash temps at room temperature. A change in temperature causes a real change in pH, not just a temperature correction.

 

Now my background is physics, not chemistry, but I have taken quite a bit of it and done well in it. It has been a while and I have not verified my statements, so I'm kind of talking out of my ass here. I'm looking forward to hearing from Basser, Brauer or Martin who can give a much more information.

[positiveContact]

i think decarbing is key here unless you can get all of the samples at the same carbonation and temp.

[Big Nake]

I could get all of the samples at the same carb and temp by leaving them out... they will be flat and room temp. But will that process impact the pH?

[positiveContact]

I could get all of the samples at the same carb and temp by leaving them out... they will be flat and room temp. But will that process impact the pH?

 

other than the changes due to decarbing and temp, I would think not.  it should provide an apples to apples comparison.

[Brauer]

i think decarbing is key here unless you can get all of the samples at the same carbonation and temp.

I agree.

[SchwanzBrewer]

I think that doesn't matter. I think Ken is onto something. You want the carb and you want it at your drinking temperature. This might not relate to anyone but him since it's going to be his taste buds, but knowing the PH and knowing whether you like the beer is important. I wouldn't decarb, I would use some lactic and lower the PH a little in the glass and see if it helps the flavor. If you can raise the PH, I'd try that too on another glass. If you can't find a PH that make the beer good, then just maybe the beer isn't what you like and you can modify the recipe. If you find the beer tastes better then you can try and modify the recipe or process so it turns out a little different. If you really want to get fancy, buy a carb meter so you know what the carb level of the beer is too so you can adjust that variable as well and know specifically what to aim for.

[positiveContact]

I think that doesn't matter. I think Ken is onto something. You want the carb and you want it at your drinking temperature. This might not relate to anyone but him since it's going to be his taste buds, but knowing the PH and knowing whether you like the beer is important. I wouldn't decarb, I would use some lactic and lower the PH a little in the glass and see if it helps the flavor. If you can raise the PH, I'd try that too on another glass. If you can't find a PH that make the beer good, then just maybe the beer isn't what you like and you can modify the recipe. If you find the beer tastes better then you can try and modify the recipe or process so it turns out a little different. If you really want to get fancy, buy a carb meter so you know what the carb level of the beer is too so you can adjust that variable as well and know specifically what to aim for.

 

i would guess that back adjusting pH like that might help in some ways it can't in others.  there are probably interactions between yeast and pH that couldn't be recreated simply by adjusting pH in the glass.

[SchwanzBrewer]

i would guess that back adjusting pH like that might help in some ways it can't in others.  there are probably interactions between yeast and pH that couldn't be recreated simply by adjusting pH in the glass.

 

I agree. but if PH is the only issue, then adjusting it could make the beer better and give you an aiming point. 

[positiveContact]

I think that doesn't matter. I think Ken is onto something. You want the carb and you want it at your drinking temperature.

 

I think the point of the decarbing was to take the effects of CO2 on pH out of the reading.  he could then see what the pH difference is on his beers compared to some commercial examples that he likes.

 

the method you are describing is still useful - just not for the sake of comparison to commercial brews.

[Big Nake]

But the pH during the brewing process may have caused a problem (tannins, etc) and that wouldn't be helped by an after-fermentation adjustment. I never really considered adjusting the pH of the finished beer because I figured it was not fixable.

[SchwanzBrewer]

I think the point of the decarbing was to take the effects of CO2 on pH out of the reading.  he could then see what the pH difference is on his beers compared to some commercial examples that he likes.

 

the method you are describing is still useful - just not for the sake of comparison to commercial brews.

 

Didn't realize he wanted to compare to commercial brews. (probably didn't read the whole post!)

[neddles]

But the pH during the brewing process may have caused a problem (tannins, etc) and that wouldn't be helped by an after-fermentation adjustment. I never really considered adjusting the pH of the finished beer because I figured it was not fixable.

I think you could definitely alter the pH downward of the finished beer to your liking with phosphoric acid and not have adverse flavor effects. Not sure how to raise it without flavor effects, baking soda? But yes, if you have a tannin issue because of mash/sparge dynamics, that won't be fixable.

Edited by ettels4, 10 March 2014 - 12:36 PM.