Author Topic: true effect of pH on finished beer  (Read 2933 times)

Offline brewinhard

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true effect of pH on finished beer
« on: September 27, 2016, 05:06:24 PM »
Now, I am not claiming any experimental data, only what I observed on a recent brew of my american blonde ale this summer and wanted to report it.

I set up my water profile to hit a 5.4 pH as I do with a lot of styles. I had brewed this recipe about 2 mos prior to this and hit it dead on. After 15 minutes, I pulled a sample for testing, and only achieved a 5.08. I added about 1 gram of baking soda back to the mash, measured again 15 minutes later, and was sitting at a 5.9. So, now I am all over the place with regards to pH. Stupid me, adds some lactic acid, and it plummetted down to a 5.01, where I left it for the remaining 30 minutes (albeit frustrated).  I typically do not chase the pH around like this, but was making the beer for a friends wedding and really wanted to produce a good product for him.

Sparge and boil went fine, but came up about 4 gravity points low (1.046) on an intended 1.050 OG (probably due to being a bit out of range for conversion, I thought). Everyone always talks about how a 5.2 mash pH can lead to a tartness in the beer, so I was expecting that.

Long story short, served it at the wedding and I did not pick up any off-flavors (even after 10 beers  :D). Sent it off to a comp for judging, and it took a gold in its category against american pale ales. So herein lies my quandary....

Do we as home enthusiasts (and possibly wanna be scientists), over emphasize the importance of mash pH, or does the mash pretty much work itself out providing you mix it with warm water and rest? I do understand that beers can be improved per style based on a proven mash pH, but sometimes I feel that it doesn't always make a difference. Is this just another case of too many variables to really focus on?

What thoughts do you have?

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Re: true effect of pH on finished beer
« Reply #1 on: September 27, 2016, 05:19:45 PM »
I think if you were looking for off flavors you were looking for the wrong thing.  A difference in mash pH will produce subtle differences in the beer, but I think you'd have to be off a lot more than you were to get off flavors.
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Offline kramerog

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Re: true effect of pH on finished beer
« Reply #2 on: September 27, 2016, 05:33:38 PM »
Having worked in a chemistry lab, I have not much faith in isolated pH readings taken in home breweries although I understand that there are some reliable pH meters out there.

I am somewhat skeptical as to the signficance of small variations in mash pH on final pH because most of the acidity in finished beer appears to be produced by yeast.  To illustrate this point in a perhaps oversimplified fashion, if the pH of the mash was 5.5 and the finished pH was 4.5, then there the finshed beer has 10 times H+ as the mash.   

Offline mabrungard

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Re: true effect of pH on finished beer
« Reply #3 on: September 27, 2016, 06:28:27 PM »
I strongly caution against chasing mash pH. If you have used a reliable mashing chemistry calculator, the pH is more likely to be within a tenth or two of your target. In addition, I've found that mashing pH consistently tends to correct itself toward a pH of about 5.4. So if you measure an overly low pH, it will rise during the mash duration. And the opposite occurs if the early pH was too high.

This seems to confirm the RDWHAHB mantra.
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Offline Wort-H.O.G.

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Re: true effect of pH on finished beer
« Reply #4 on: September 27, 2016, 06:34:58 PM »
Now, I am not claiming any experimental data, only what I observed on a recent brew of my american blonde ale this summer and wanted to report it.

I set up my water profile to hit a 5.4 pH as I do with a lot of styles. I had brewed this recipe about 2 mos prior to this and hit it dead on. After 15 minutes, I pulled a sample for testing, and only achieved a 5.08. I added about 1 gram of baking soda back to the mash, measured again 15 minutes later, and was sitting at a 5.9. So, now I am all over the place with regards to pH. Stupid me, adds some lactic acid, and it plummetted down to a 5.01, where I left it for the remaining 30 minutes (albeit frustrated).  I typically do not chase the pH around like this, but was making the beer for a friends wedding and really wanted to produce a good product for him.

Sparge and boil went fine, but came up about 4 gravity points low (1.046) on an intended 1.050 OG (probably due to being a bit out of range for conversion, I thought). Everyone always talks about how a 5.2 mash pH can lead to a tartness in the beer, so I was expecting that.

Long story short, served it at the wedding and I did not pick up any off-flavors (even after 10 beers  :D). Sent it off to a comp for judging, and it took a gold in its category against american pale ales. So herein lies my quandary....

Do we as home enthusiasts (and possibly wanna be scientists), over emphasize the importance of mash pH, or does the mash pretty much work itself out providing you mix it with warm water and rest? I do understand that beers can be improved per style based on a proven mash pH, but sometimes I feel that it doesn't always make a difference. Is this just another case of too many variables to really focus on?

What thoughts do you have?

FWIW 1gr of baking soda should not have caused a swing from low 5.08 to 5.9...i think some measurement/reading errors here.

there are documented suggested/optimal mash PH for styles. also documented suggested/optimal PH for beta and alpha amylase. also  documented suggested/optimal PH for finished product by style. I've played around with all of these and not entirely sure the significance (within range of 5.1-5.8ish) in the mash variations vs. post mash PH adjustments. 

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Offline zwiller

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Re: true effect of pH on finished beer
« Reply #5 on: September 27, 2016, 06:41:50 PM »
I strongly caution against chasing mash pH. If you have used a reliable mashing chemistry calculator, the pH is more likely to be within a tenth or two of your target. In addition, I've found that mashing pH consistently tends to correct itself toward a pH of about 5.4. So if you measure an overly low pH, it will rise during the mash duration. And the opposite occurs if the early pH was too high.

This seems to confirm the RDWHAHB mantra.

+1;  I put BNW through it's paces and trust it.  pH meters are wonky devices. 
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Re: true effect of pH on finished beer
« Reply #6 on: September 27, 2016, 07:21:21 PM »
I've played around with all of these and not entirely sure the significance (within range of 5.1-5.8ish) in the mash variations vs. post mash PH adjustments. 

Same here. I lowered pH in kettle on 3 or 4 straight German beers and am not sold on it as something to keep doing. I liked the theory, but the actual results were mixed over just riding with mash pH IMO.



I strongly caution against chasing mash pH. If you have used a reliable mashing chemistry calculator, the pH is more likely to be within a tenth or two of your target. In addition, I've found that mashing pH consistently tends to correct itself toward a pH of about 5.4. So if you measure an overly low pH, it will rise during the mash duration. And the opposite occurs if the early pH was too high.

This seems to confirm the RDWHAHB mantra.

+1;  I put BNW through it's paces and trust it.  pH meters are wonky devices. 


+2.  This why I still don't (and probably won't) own a pH meter - mash pH wants to stabilize near 5.4, within reason.  Nearly all the brewers who post here check mash pH and, regardless of the reading, nearly all 'let it ride'.  Even Martin says that chasing mash pH is not a good thing to do. I know different maltsters put out malts on occasion that are more acidic than usual, but my results are consistently what I want with Brunwater. Just not looking to fuss over a temperamental meter that's prone to erroneous readings if not handled correctly. Who knows, never say never.
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Re: true effect of pH on finished beer
« Reply #7 on: September 28, 2016, 01:28:23 AM »
I'm thinking of adding 1/4 tsp baking soda at 15 and then 1 tsp of acid at 30 to see if I can replicate these golden results...no wedding planned though...
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Offline juggabrew303

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Re: true effect of pH on finished beer
« Reply #8 on: September 28, 2016, 04:46:00 AM »
I've played around with all of these and not entirely sure the significance (within range of 5.1-5.8ish) in the mash variations vs. post mash PH adjustments. 

Same here. I lowered pH in kettle on 3 or 4 straight German beers and am not sold on it as something to keep doing. I liked the theory, but the actual results were mixed over just riding with mash pH IMO.



I strongly caution against chasing mash pH. If you have used a reliable mashing chemistry calculator, the pH is more likely to be within a tenth or two of your target. In addition, I've found that mashing pH consistently tends to correct itself toward a pH of about 5.4. So if you measure an overly low pH, it will rise during the mash duration. And the opposite occurs if the early pH was too high.

This seems to confirm the RDWHAHB mantra.

+1;  I put BNW through it's paces and trust it.  pH meters are wonky devices. 


+2.  This why I still don't (and probably won't) own a pH meter - mash pH wants to stabilize near 5.4, within reason.  Nearly all the brewers who post here check mash pH and, regardless of the reading, nearly all 'let it ride'.  Even Martin says that chasing mash pH is not a good thing to do. I know different maltsters put out malts on occasion that are more acidic than usual, but my results are consistently what I want with Brunwater. Just not looking to fuss over a temperamental meter that's prone to erroneous readings if not handled correctly. Who knows, never say never.
Exactly why I haven't been convinced that I need a PH meter.  IMO not enough advancement in technology of meters to be accurate and cost effective for home brewers. 


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Re: true effect of pH on finished beer
« Reply #9 on: September 28, 2016, 12:54:55 PM »
I am somewhat skeptical as to the signficance of small variations in mash pH on final pH because most of the acidity in finished beer appears to be produced by yeast.  To illustrate this point in a perhaps oversimplified fashion, if the pH of the mash was 5.5 and the finished pH was 4.5, then there the finshed beer has 10 times H+ as the mash.

+1

The final pH is driven by the fermentation.  However, kettle pH does matter for mallaird reactions, hop flavor, and other reasons.
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Offline zwiller

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Re: true effect of pH on finished beer
« Reply #10 on: September 28, 2016, 01:42:53 PM »
Final pH is driven by the yeast but the brewer has to set it up to get there.  If you do any research, it is rare for the yeast to drop the pH when mashed/sparged out of range.  There is an expected pH drop and if you start high, you end high.  There is no autocorrect.  IE - Chico is a low acid producer.  SN is well known to acidify all brewing water to 5.5 and mash at 5.1... 

My second pH meter was dedicated to measuring all phases of brewing that cannot be mathematically predicted.  IE pre-boil/KO/final and the findings were quite revealing.  Final pH was mind blowing.  ALL of my homebrews were higher than 4.5, not by a little, by a lot.  And I was fastidious about pH including acidifying sparge BUT I was was using Chico...  BTW a final pH of 4.5 is considered the norm as it a pH where no biological contaminants can survive in.  IIRC commercial packaged beer must meet this requirement.  All this said, the high pH beer didn't really taste bad it just doesn't taste as good, kinda dull/flat/tubby.  Dialing in final pH is taking a good beer to great. 
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Offline narvin

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Re: true effect of pH on finished beer
« Reply #11 on: September 28, 2016, 02:31:13 PM »
Final pH is driven by the yeast but the brewer has to set it up to get there.  If you do any research, it is rare for the yeast to drop the pH when mashed/sparged out of range.  There is an expected pH drop and if you start high, you end high.  There is no autocorrect.  IE - Chico is a low acid producer.  SN is well known to acidify all brewing water to 5.5 and mash at 5.1... 


A lot of that is for reducing alkalinity in the water (buffering), which prevents pH from dropping and results in a high mash pH.  So yes, kettle pH is important.  But it's a logarithmic scale so the amount of hydrogen ions that cause a pH drop from 5.5 to 5.2 would do something like drop pH 4.5 to 4.47 (total swag but you get the idea).

Whether there is significant buffering capability removed below a certain wort pH, I'm not sure.  Would be interesting to see some experiments.
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Re: true effect of pH on finished beer
« Reply #12 on: September 28, 2016, 03:00:53 PM »
zwiller - "a final pH of 4.5 is considered the norm as it a pH where no biological contaminants can survive in."

A finished beer does drop into the 4.1-4.5 pH ranges.  However "no biological contaminants can survive" is a false statement.
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Offline zwiller

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Re: true effect of pH on finished beer
« Reply #13 on: September 28, 2016, 03:37:52 PM »
Final pH is driven by the yeast but the brewer has to set it up to get there.  If you do any research, it is rare for the yeast to drop the pH when mashed/sparged out of range.  There is an expected pH drop and if you start high, you end high.  There is no autocorrect.  IE - Chico is a low acid producer.  SN is well known to acidify all brewing water to 5.5 and mash at 5.1... 


A lot of that is for reducing alkalinity in the water (buffering), which prevents pH from dropping and results in a high mash pH.  So yes, kettle pH is important.  But it's a logarithmic scale so the amount of hydrogen ions that cause a pH drop from 5.5 to 5.2 would do something like drop pH 4.5 to 4.47 (total swag but you get the idea).

Whether there is significant buffering capability removed below a certain wort pH, I'm not sure.  Would be interesting to see some experiments.
On another forum there is semi active thread comparing the pH drop of KO to final.  The final drop is not log based or minor like you describe.  Perhaps this can be explained but that is beyond me.  It's just something I've picked up from experience. 
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Re: true effect of pH on finished beer
« Reply #14 on: September 28, 2016, 03:51:40 PM »
Yeast strain can have an influence. Lagers end up higher, ales lower.
http://byo.com/malt/item/1494-the-principles-of-ph

Certain pathogens do not survive under 4.6 pH. This is why pickled foods are safe. Brett survives at lower pH, as does lactic and acetic organisms.

Edit - one can drop pH in the finished beer with the acid of your choice (phosphoric is most flavor neutral), or raise the pH with a base (pickling lime is my choice). Try it.
« Last Edit: September 28, 2016, 03:54:15 PM by hopfenundmalz »
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