Issues with Mash pH

[bodkincreek]

Hey guys,
This past weekend, i tried my hand at adjusting the water chemistry and pH of my beer. I'm not exactly well versed in water chemistry and adjustment of pH, but I thought I had a general grasp of the basics.

I followed the recipe for the Hoppy Session Wheat Beer in the link below. I followed the water treatment guidelines laid out in the recipe, and used Bru'n Water to make sure I hit the mineral numbers called out in the recipe. Everything checked out in Bru'n water.
https://www.homebrewtalk.com/forum/threads/hoppy-session-wheat-beer.644047/

However, the day of the brew, I couldn't get RO water, so I did 50/50 split of Deere Park Spring Water and Distilled water. I figured, "what could go wrong".

I proceeded with the brewing day, added the gypsum and Calcium Chloride and the Lactic acid as planned. I mashed in, waited 15 mins, checked the pH and it tested out at 6.5. The Bru'n Water spreadsheet said i should have a pH of 5.35... So i added some more lactic acid (1.25ml) and the pH didn't budge. I added another 1.25ml of lactic acid. Still didn't budge. At that point, I just left it alone and finished the mash.

The pH meter i have is a Hana. I actually had two of them, I calibrated them both and they were both reading just about the same. So i don't think that the pH meter was the problem.

I guess my question is would the 50/50 mix of Spring Water and Distilled water really thrown my pH off that much? I looked at the Deere Park water analysis, and assuming i'm reading it correctly, it shouldn't have played that much of a role?

Any input would be helpful!

 

[sixhotdogneck]

Guessing never works.

Obviously the bottles of spring water you purchased had more alkalinity than you expected and given the analysis sheet it can vary from none detected to up to 100ppm alkalinity CaCO3 (in 2017, not sure about now, it may be more), the same with Ca, SO4, Na, etc... such that diluting by 50% (which you guessed at) wouldn't make enough of a difference.

What you should have done is go with all distilled and rerun the spreadsheet analysis. Waiting at least 25-30 minutes before taking a reading is also advisable.

 

[Silver_Is_Money]

I'm surprised that 2.5 mL of 88% lactic acid did not budge the mash pH, even a little. I would 'initially' presume a shift on the order of ~0.20 to ~0.30 pH points downward.

What was your batch size? Did you sparge, or do a no-sparge mash?

Were the pH meters calibrated in close proximity to the mash? Did both of them read 6.5?

Which version of BW are you using?

 

[ajdelange]

Something is very wrong. Yes, you would, in the absence of any acid additions have the potential for a high mash pH as wheat malt and flaked barley and oats all have high DI mash pH's. Absent any acid additions mash pH could well be over 5.8 (5.35 isn't a reasonable estimate and 6.5 is an unreasonably high measurement unless the blended water had alkalinity approaching 19 mEq/L ~ 950 ppm as CaCO3) and you would need, for those grain masses and a target pH of 5.5, about 7 mL of lactic acid. But even if you only added a total of 2.5 you should have seen a mash pH drop of about 0.7 pH units. The fact that you saw no drop at all is very troubling.
First, and always when something doesn't make sense, check the pH meter. Second, be sure the lactic acid is well mixed. Withdraw a quart or so of liquid, add the acid to that, stir thoroughly and then add the acidified liquid back to the mash with vigorous stirring. Third, give the acid some time to penetrate the grist particles and react.

 

[IslandLizard]

Did you stir really well after adding the extra Lactic Acid? How thick was the mash (qts/lb)? It may have stratified and your samples weren't representative.

I've found it quite useless tweaking the mash pH during the mash, as when you should take your sample, 30' in, the mash has already more than half completed conversion. A test mash with half a pound or so of the grist mix is a much better way.

 

[sixhotdogneck]

Not sure where you got your distilled water but I've seen distilled with more alkalinity than RO water. Not sure if this stuff is regulated but it may have been produced with RO/DI equipment that needed servicing and was labeled distilled.

The variance in that Spring Water, especially if it came from one well and is not a measured blend of waters, could very well have alkalinity well above what is on the water report.

 

[ScrewyBrewer]

However, the day of the brew, I couldn't get RO water, so I did 50/50 split of Deere Park Spring Water and Distilled water. I figured, "what could go wrong".

Yep, now there's the problem. As the others have suggested. Trying to predict a given mash pH value when using water with unknown properties is a recipe for frustration.

 

[IslandLizard]

Yep, now there's the problem. As the others have suggested. Trying to predict a given mash pH value when using water with unknown properties is a recipe for frustration.

In that light, when one has water of unknown composition, would it be advisable to add an acid, drop-wise, to a liter of it and track pH changes. A poor man's titration.

 

[bodkincreek]

I'm surprised that 2.5 mL of 88% lactic acid did not budge the mash pH, even a little. I would 'initially' presume a shift on the order of ~0.20 to ~0.30 pH points downward.

What was your batch size? Did you sparge, or do a no-sparge mash?

Were the pH meters calibrated in close proximity to the mash? Did both of them read 6.5?

Which version of BW are you using?

The batch size was 6.5 gallons into the fermenter. I did a fly sparge.

One pH meter was brand new, the other was lightly used. I calibrated the pH meters using the 7.01 and 4.01 calibrating solutions that are provided with the meter. Both read 6.5pH.

I'm using Bru'n Water version 1.18a.

Something is very wrong. Yes, you would, in the absence of any acid additions have the potential for a high mash pH as wheat malt and flaked barley and oats all have high DI mash pH's. Absent any acid additions mash pH could well be over 5.8 (5.35 isn't a reasonable estimate and 6.5 is an unreasonably high measurement unless the blended water had alkalinity approaching 19 mEq/L ~ 950 ppm as CaCO3) and you would need, for those grain masses and a target pH of 5.5, about 7 mL of lactic acid. But even if you only added a total of 2.5 you should have seen a mash pH drop of about 0.7 pH units. The fact that you saw no drop at all is very troubling.
First, and always when something doesn't make sense, check the pH meter. Second, be sure the lactic acid is well mixed. Withdraw a quart or so of liquid, add the acid to that, stir thoroughly and then add the acidified liquid back to the mash with vigorous stirring. Third, give the acid some time to penetrate the grist particles and react.

I added the lactic acid directly to the mash and stirred it vigorously. I checked the pH at 15 mins in, added lactic acid, checked it 30 mins in, added more lactic acid and checked it at 45 mins in. All three times, the mash came it around 6.5ish. I pulled the sample from the valve and pulled a sample from the top of the mash, mixed the two together and checked the pH.

 

[bodkincreek]

Did you stir really well after adding the extra Lactic Acid? How thick was the mash (qts/lb)? It may have stratified and your samples weren't representative.

I've found it quite useless tweaking the mash pH during the mash, as when you should take your sample, 30' in, the mash has already more than half completed conversion. A test mash with half a pound or so of the grist mix is a much better way.

I like to think I stirred the mash very well to get rid of any dough balls and to fully saturate the grains. The mash was 1.5qts per pound of grain.

 

[IslandLizard]

I pulled the sample from the valve and pulled a sample from the top of the mash, mixed the two together and checked the pH.

The valve and connected deadspace do not yield representative samples from your mash. The very top may not either. Pull the sample from the center somewhere.

I strain the 1/4 cup sample through a small sieve to remove the thick part, and capture 1/2 an ounce or so of the wort in a frozen shot glass. After stirring the sample is usually around 25C by then.

 

[Silver_Is_Money]

BW is up to version 1.24 as of the last time I checked. Output has changed. But I don't believe the free version of BW offers selections for wheat or for flaked grist components, some of which can be quite high in pH, and it lumps these into the "base" category, which is not as high in pH. But even allowing for this plus allowing for high alkalinity I still can't imagine measuring 6.5 pH for this mash. 5.9(ish) pH perhaps.

 

[ajdelange]

In that light, when one has water of unknown composition, would it be advisable to add an acid, drop-wise, to a liter of it and track pH changes. A poor man's titration.

Why limit the sample to 1 L? Why not titrate the whole volume to mash pH? You have, in so doing, zeroed the effective alkalinity of the water. This is the Zero Effective Alkalinity method. This combines the "poor man's titration" and the process of having to calculate and measure out the acid.

Now you can take a pound of the grist, mash it with this 0 alkalinity water and check the pH. Add acid as required to hit the desired mash pH and scale the amount to the total grist weight.

 

[bodkincreek]

The valve and connected deadspace do not yield representative samples from your mash. The very top may not either. Pull the sample from the center somewhere.

I strain the 1/4 cup sample through a small sieve to remove the thick part, and capture 1/2 an ounce or so of the wort in a frozen shot glass. After stirring the sample is usually around 25C by then.

Thank you for the input. At the time, i figured the bottom and top would be a good way to represent the mash pH but now that I think about it, you're right. I should have pulled from the middle of the mash.

BW is up to version 1.24 as of the last time I checked. Output has changed. But I don't believe the free version of BW offers selections for wheat or for flaked grist components, some of which can be quite high in pH, and it lumps these into the "base" category, which is not as high in pH. But even allowing for this plus allowing for high alkalinity I still can't imagine measuring 6.5 pH for this mash. 5.9(ish) pH perhaps.

I'll download the more recent version. Is there another water chemistry resource that i should use in lieu of the Bru'n Water spreadsheet? I thought Bru'n Water was the best resource out there. I have the Beersmith software. Should i use that instead?

 

[ajdelange]

See No. 2 at https://www.homebrewtalk.com/forum/...rs-stunned-no-answer-yet.657312/#post-8424262 for a discussion on brewing calculators and spreadsheets.

 

[ScrewyBrewer]

In that light, when one has water of unknown composition, would it be advisable to add an acid, drop-wise, to a liter of it and track pH changes. A poor man's titration.

I suppose someone would take that approach if they were willing to devote the time needed. For me, it's just 100 times easier to start out with RO water and eliminate all the extra effort and guesswork.