Very High Post Boil pH

[Bobo1898]

Brewed a Kolsch-style beer today and ran into an interesting problem.

All seemed to go well by the time I took my gravity reading post boil. When I went to check my pH, the sample had a pH of 10.02! I calibrated my meter when I took my mash pH so there shouldn't have been any issues. My mash pH was 5.2. When I smelled my sample with a pH of 10.02, it smelled like fish food and brewery cleaner.

I took another sample in a different vessel and it smelled better to okay. But the pH reading was still high---6.80!

Anyone else have a high pH, post boil like this? Or would anyone know the cause of this? Here was the grain bill and process:

Pils (73.2%)
Vienna (20.9%)
Wheat (5.9%)

Mashed @ 146° for 75 minutes and then 158° for 30 minutes. 10 minute mash out @ 168°. Boiled for 90 minutes with a few hop additions (Tettnang and Hallertau) that targeted 20 IBUs.

I work from Distilled Water and build up from there. Along with the usual salts, I added lactic acid to the mash. However, for the sparge water volume, Bru'n Water said I needed 0.01ml of lactic acid so I opted against adding any because it was so minimal. I did not take a pH reading after my initial mash reading until post-boil.

After the fact, while cleaning, I noticed in both the mash tun and boil kettle, that were some shards from the grain sack. I used an empty Weyermann sack to transport the grains and to make it manageable to pour my grains into the mill, I cut the bag in half---it easily splintered and some shards of this made its way into the batch. So I mashed and boiled with a few pieces of grain sack in the wort. But I don't imagine this would be the cause of such a high pH.

Would the beer be a lost cause with the pH so high? I don't plan on pitching the yeast until the morning as the beer is dropping the remaining 10 degrees to fermentation temp.

As for the weird cleaner/fish food smell in the first sample, I typically clean my kettles and fermenters with Craft Meister Alkaline Brewery Wash and then give it a good rinse afterwards. The kettles don't smell like cleaner.

Should I dump this batch?

 

[day_trippr]

Is it possible something you added was mislabeled? Because that would be my guess - and I would favor dumping anything that you aren't 100% confident doesn't have an unwanted ingredient that might cause harm. It's not worth the risk.

The plastic from the grain bag would not be the root cause of whatever is going on. Something else is in play here, imo.
Did you happen to have added an entire jar of yeast nutrient to the wort along the way?

 

[Bobo1898]

Thanks for the quick reply @day_trippr !

Did you happen to have added an entire jar of yeast nutrient to the wort along the way?

That would be a disaster. No, I added 1 tsp of Fermax. And I also added 1 (maybe 3/4) of a whirlfloc tablet. Both of these were with 5 minutes left in the boil.

Whirlfloc might explain the fish food smell, but I'm not sure. I've used the Fermax before without issue. Does yeast nutrient raise the pH?

All my other additions----gypsum, calcium chloride, epsom salt, kosher salt, lactic acid and ascorbic acid---are open items that I've been using so there shouldn't be an issue there.

Could it be I didn't rinse off enough of the alkaline cleaner from my previous brew-day? I just started using Craft Meister after coming from One Step Cleaner and PBW before that. Typically I recirculate the cleaner through my mash tun for 30 minutes @ 150°, then transfer this to my boil kettle for another 30 minutes @ 150°. I drain this then use my faucet spray to rinse the kettles. To rinse cleaner from my pump and RIMS element, I just hold it over the sink and let water run through it (meaning I don't turn them on for the rinse process).

 

[day_trippr]

Yeast nutrient is the only thing I have experience with wrt brewing that can have an aroma that reminds me of fish - I'm assuming it's the DAP.

In any case, to get a 5 point pH shift between MLT and BK, and assuming you're brewing multiple gallons of beer here, something significant had to have made it into the kettle. Just too sketchy to stay the course, imo...

 

[marc1]

I would recalibrate the meter, confirm that it reads the calibration buffers correctly, and take another room temperature pH reading. If your pH is actually 10, there's something seriously wrong.

 

[Bobo1898]

So I've done 3 readings in addition to my mash reading:

Mash reading with recalibration was 5.2
First post-boil reading was 10.02----smelled like fish food and cleaner
Second post-boil reading was 6.80---smelled closer to what I expected
Third post-boil reading with recalibration was 5.75---smelled fine

Even 5.75 seems high, but much better than the two prior readings.

It's reading the buffer solutions correctly. I was ready to dump til the third reading but now I'm not sure. Maybe the meter went wonky somehow between the mash and the post-boil sample?

 

[HopSing]

Is it possible your sample vessel is / was contaminated? Assuming you're not sampling pH in the fermentation vessel itself, correct?

I also use Craft Meister cleaner. It does take a bit more rinsing and you need to rinse with hotter water than you used during the cleaning step, but I would doubt that would spike pH like that and it would also not explain the decrease.

Just a thought.

~HopSing.

 

[Bassman2003]

Other than meter issues, it is tough to know from this end. Simple questions:

Are you cooling the samples to 75F-ish before taking the reading?

How old is your calibration solution?

 

[Bobo1898]

Appreciate the response @HopSing

Assuming you're not sampling pH in the fermentation vessel itself, correct?

I did not sample pH directly in the fermentation vessel. I took it from my gravity sample tube---which I poured in a shot glass for pH testing. It's possible my shot glass was contaminated. The subsequent readings were all in different shot glasses. Maybe the first glass had residual detergent on it?

Do we all agree 5.75 is a bit high as well? The batch had 3oz of hops added to it, even though the IBUs are low----both hops had very low AA%. I know dry hopping increases pH but can't remember the effect of boil additions. Obviously this doesn't explain the 10.02 or 6.80 readings.

I have been running or soaking Craft Meister in hot water, but I've been rinsing with cold water. As you suggested, still not sure it would spike pH that much and suddenly seem fine after the fact. Good to know I should be rinsing in hot water, and will do so in the future.

 

[Bobo1898]

Are you cooling the samples to 75F-ish before taking the reading?

Yeah the first sample was around 77 at gravity reading. The small portion I poured for pH reading probably was slightly lower than that. The subsequence readings were definitely around 70.

How old is your calibration solution?

They were brand new and just opened them on brew day. Storage, Cleaning, 7.01 and 4.01 solutions.

Still haven't pitched yeast, but batch in fermentation vessel smells fine this morning.

 

[day_trippr]

Do we all agree 5.75 is a bit high as well?

Hells yes that's way high for post-boil wort...

 

[Bassman2003]

Good stuff. Kind of a head scratcher then. Yes, the batch should not normally be at 5.75 at the end of the boil. It would be tough to get that pH ever starting with distilled water. So it has to be an added outside substance or pH meter error as you have been careful with the sample handling.

 

[Indian_villager]

How old is your pH meter? Has the bulb ever fully dried out? Calibrate your meter with buffers, wait 10 minutes, and measure the same buffers again, does the meter read the buffers accurately? I just had to replace my probe after a few years of use because it would fail the retest.

When you collect a sample for measurement, do you just pour the sample into your measurement jar? I usually fill the measurement jar and dump twice and use the third fill for measurement. This is standard lab practice to reduce the impact of contamination from the measurement jar but I still use it at home.

As for your off smell your post indicates it was in the sample, did you smell it in the boil kettle as well? This makes me think even more that it was a contaminated measurement jar. Did you or someone else use the jar to weigh out PBW or something similar?

 

[Bobo1898]

How old is your pH meter? Has the bulb ever fully dried out?

The probe is maybe a year and a half old. I don't believe it's ever dried out---there's always some storage solution in the cap when I take the probe out.

So I spoke with Milwaukee Instruments to troubleshoot any potential issues with the meter and it appears that my recalibration method raises some issues:

I usually take four shot glasses----7.01, 4.01 and two vessels of cleaning solution. For this batch, I used the cleaning solution as a rinse which is wrong (in hindsight obviously wrong). I should be using distilled water in place of the cleaning solution. I've used distilled in the past before but I hadn't brewed in a few months so I just wasn't thinking. That being said, I don't know if it would raise the pH that high, right?

I ended up pitching yeast before Milwaukee got back to me so I opted not to test it right away---was running close to the 24 hour mark without pitching. I figured if I was going to dump the beer, it wouldn't matter if it was now or down the line. I wasn't going to keep the yeast anyway because I'm not going to brew for a while and if there was the slight chance the beer was fine and it was my meter, I could let it ride.

When you collect a sample for measurement, do you just pour the sample into your measurement jar? I usually fill the measurement jar and dump twice and use the third fill for measurement. This is standard lab practice to reduce the impact of contamination from the measurement jar but I still use it at home.

For both the mash readings and post-boil readings, it's the first sample pulled directly into whichever vessel I'm using. I am not pulling multiple samples as a rinse. But this is a good idea in the future. For my mash reading I typically keep two glasses in the freezer the night before and pour in one to reduce temp, then pour that sample into the second to reach room temp. If I'm using your two-three samples to reduce impact of contamination, how would I chill this to room temp---place the sample in the freezer?

As for your off smell your post indicates it was in the sample, did you smell it in the boil kettle as well?

I did not smell it in the boil kettle or the subsequent samples after the first one. When I pitched my yeast yesterday, I smelled the fermenter again and it smelled fine.

This makes me think even more that it was a contaminated measurement jar. Did you or someone else use the jar to weigh out PBW or something similar?

I'm starting to wonder the same about the glass as well as the recalibration issue I mentioned above. That glass would have come from the dishwasher so maybe it had residual soap and hard water deposits on it? But there was no PBW or cleaner measured out in the sample vessel---it was pulled straight from the cabinet.

Since I pitched the yeast, would it do any good to take another sample and recalibrate the probe? Obviously the beer pH has changed---beer has dropped around 2°P since yesterday, according to BrewSpy.

 

[mac_1103]

I used the cleaning solution as a rinse which is wrong (in hindsight obviously wrong). I should be using distilled water in place of the cleaning solution. I've used distilled in the past before but I hadn't brewed in a few months so I just wasn't thinking. That being said, I don't know if it would raise the pH that high, right?

What's the pH of the cleaning solution? If it's the Alkaline Brewery Wash you mentioned earlier then it's probably quite high and very well might explain the entire issue.

 

[Bobo1898]

What's the pH of the cleaning solution?

It's low---can't take a reading now but it's definitely below 3 and close to 2.

If it's the Alkaline Brewery Wash you mentioned earlier then it's probably quite high and very well might explain the entire issue.

This would make sense as to why it was 10.02 in the first reading, but the batch smells fine and subsequent readings have been lower. But again, I couldn't say the brewery wash got into the sample vessel or the pots and fermenter. Unless rinsing alkaline wash with cold water doesn't remove it at all.

The glasses I use for sampling don't cross the brewery wash----they go in the dish washer and get dipped in Star San when sampling post-boil and post-fermentation.

 

[tracer bullet]

When I'm calibrating, I rinse with DI water and blow off as much as I can. I think that even that tiny bit of carry-over can affect the readings slightly, 0.1, 0.2 kind of amounts. It's sort of:

Take it out of the storage solution
rinse w/ di water, blow off as much as I can
put into 4.00 solution to check
rinse w/ di water, blow off as much as I can
put into 7.00 solution to check
rinse w/ di water, blow off as much as I can
put into wort to measure
rinse w/ di water, blow off as much as I can
put into storage solution and put away until next brew

I mention it in case you do something completely different, maybe the above would help? You might do something similar and if so never mind.

 

[Bobo1898]

I mention it in case you do something completely different, maybe the above would help?

Yeah this is basically the process I use, except I made the mistake of using cleaning solution instead of distilled water on this particular brew day.

 

[Bobo1898]

Maybe I should rinse my sample vessels with distilled water a couple times to be on the safe side, moving forward.

 

[Bassman2003]

I would say just keep your calibration routine separate from your sample routine and make sure to rinse any kind of alkaline cleaner with hot water and you will be good. Also, a quick rinse of the probe every time it comes out of storage solution as well.

 

[Hoochin'Fool]

When I'm calibrating, I rinse with DI water and blow off as much as I can. I think that even that tiny bit of carry-over can affect the readings slightly, 0.1, 0.2 kind of amounts. It's sort of:

Take it out of the storage solution
rinse w/ di water, blow off as much as I can
put into 4.00 solution to check
rinse w/ di water, blow off as much as I can
put into 7.00 solution to check
rinse w/ di water, blow off as much as I can
put into wort to measure
rinse w/ di water, blow off as much as I can
put into storage solution and put away until next brew

I mention it in case you do something completely different, maybe the above would help? You might do something similar and if so never mind.

As a lazy slob who just relies on Brewer's Friend to tell me how much phosphoric acid I need to add for a specific grist and water profile, I gotta say that doing a "real pH check" seems like a lot of trouble! Do you do that for every brew-day? Or just for new recipes that you haven't made before?

 

[Bobo1898]

As a lazy slob who just relies on Brewer's Friend to tell me how much phosphoric acid I need to add for a specific grist and water profile, I gotta say that doing a "real pH check" seems like a lot of trouble! Do you do that for every brew-day? Or just for new recipes that you haven't made before?

Hahaha, I try to do it every batch because I make a lot of small tweaks here and there. And my hop amounts change every batch due to AA% of the inventory at my LHBS. Since my water is from scratch, hypothetically once I dial everything in, I may not need to do it every batch.

But had I not checked pH in this batch, I wouldn't have noticed a problem. I would have dumped my gravity sample and let the batch go. Again, if it's a matter of contaminant in my sample vessel, then I've created a panic storm for myself for no reason. If it's something definitely in the beer, then it was good I checked my post-boil pH.

 

[tracer bullet]

As a lazy slob who just relies on Brewer's Friend to tell me how much phosphoric acid I need to add for a specific grist and water profile, I gotta say that doing a "real pH check" seems like a lot of trouble! Do you do that for every brew-day? Or just for new recipes that you haven't made before?

I actually do it each time, but it's during the boil and I'm just hanging around so it's hardly extra work. Goes pretty quickly too.

I really don't need to, the only times I actually detect anything are yes for a new recipe, or any major change to one (getting ingredients from a new shop, or changing from pale malt to maris otter). Some recipes I hit pretty close time and again so I probably could start skipping those.

 

[Indian_villager]

Few things. This sounds like a contamination, remember that pH is a logarithmic scale so the difference between 5 and 10 is actually 10^5 ( less available hydrogen ions).

Follow Milwaukees guidance on calibration.

I have their MW102 these things are rated to read up to 70 °C (158 °F) So you don't need to go through the hassle of cooling down your mash too much. Additionally using frozen glasses further increases the potential for contamination as your sample now has a bunch of water from the frost/condensate on your glass. I use a cleaned beaker which I dunk into the top of the mash, pour back into the top of the mash while it is recirculating, and repeat until my beaker is filled for the third time. I use that to measure. And I measure at elevated temperature without issue. After measuring I return the probe to some RO water. After all my beer samples have been measured for the brew day, then I hit it with the cleaning solution, rinse in fresh RO, and then put on the cap with the storage solution.

 

[Bassman2003]

Cooling the sample to 70ish F is the international standard for brewing pH measurement. I think it is best to follow this standard so your results follow others' results etc...

 

[tracer bullet]

PH at mash temps seems to read about 0.2 below the pH if measured at room temp. From all the times I've seen people measure both, which has been a few over the years here, that's about what it is. 5.2 at mash temp will probably be about 5.4 when cooled.

I do agree to measure at room temp, not trying to say anything contrary. But if one does measure at an elevated temp that might be about how far off they can expect to read.

 

[VikeMan]

When I'm calibrating, I rinse with DI water and blow off as much as I can. I think that even that tiny bit of carry-over can affect the readings slightly, 0.1, 0.2 kind of amounts.

I shake/blot distilled water off before taking a reading. That said, a few drops of distilled water in a shotglass full of calibration buffer or wort won't affect the reading (assuming it all gets mixed homogenously). Distilled water has no buffering capacity, so any pH shift has to be due strictly to dilution. And there's not enough dilution in this case to matter.

 

[DuncB]

Take a sample of the part fermented wort and taste it.
Once you are sure your meter is calibrated correctly. Take a ferment reading and you can then add some lactic acid or phosphoric acid to bring the pH down. If you want.

 

[Bobo1898]

UPDATE. I added 2ml of lactic acid to this before fermentation cause I figured why not if I'm going to toss it. Post fermentation pH hit 4.5 which is normal, but with the caveat of how it got there. Beer tastes good and seems to be in good shape.

Brewed a saison today and followed the proper calibration steps (as to not make the same mistake as last time) and hit a mash pH of 5.45 when I was targeting a pH of 5.3. I added 1ml of lactic acid and remeasured to reach 5.38 which I felt was acceptable. Both readings were around room temp.

Post boil pH is HIGH AGAIN. 5.76 this time. Gravity sample smelled and tasted fine as opposed to the previous batch. Both pH and gravity reading were taken at at 68°F.

Calibration solutions are reading correctly, so I'm not quite sure. I started rinsing my alkaline cleaner with hot water but maybe it's still not getting off.

One thing is, I build up from distilled water and Bru'n Water tells me to add 0.01ml of lactic acid to my sparge water. I'm not quite sure how to measure this so I forgo this acid addition because it's so small. But I doubt it would be the cause of why my pH would be so high. But it made me think that maybe I do need to add lactic acid to my sparge---half the amount of what I add to the mash or something?

 

[day_trippr]

Something is definitely not right with that post-boil pH reading- typically the boil DROPS pH by one or two tenths of a point. But I can't believe you could have enough alkaline cleaner residue in a kettle to shift the pH of a batch of beer that much - unless you left a standing puddle of it

Gotta be another answer...

Cheers!

 

[VikeMan]

Something is definitely not right with that post-boil pH reading- typically the boil DROPS pH by one or two tenths of a point.

Yep. At this point, my guess would be faulty/drifting meter.

 

[marc1]

When are you measuring your mash pH?

 

[Bobo1898]

For the Kolsch (first post), 15 minutes into the first step. I do this for all brews except for step mashes than start below 131.

For the Saison, I do a step mash and I take the measurement later than usual. I do a ferulic acid rest for 15 minutes and then bump to 131. When I got to 131, I took it ten minutes later. So in this case, maybe 30-35 minutes into the mash. This is when the pH was 5.45. After adding another 1ml of lactic acid and letting it recirculate and remeasuring, I had reached my step at 144. My pH was 5.38. This was probably 40-45 minutes into the mash.

 

[HopSing]

What was the pH of your sparge water? Next batch take pH samples of everything at every step. You could have a contamination (residual cleaner) but as @day_trippr said, it should not impact it that much. One thing you can try is to StarSan after your cleaner rinse. That may neutralize the pH from the cleaner, but I'm spitballing.

~HopSing.

 

[Bobo1898]

What was the pH of your sparge water?

I did not measure my sparge water pH. It's just distilled water. But I am treating it with some gypsum, calcium chloride, epsom salt, and canning salt. Perhaps I'll test this next time as you suggest.

One thing you can try is to StarSan after your cleaner rinse. That may neutralize the pH from the cleaner, but I'm spitballing.

I did stop sanitizing hot side, recently. I'll give this a shot too.

One other factor is, my yeast nutrient changed. I used to use the Wyeast yeast nutrient but the store I shop at no longer carries it. So I switched to Fermax, which contains diammonium phosphate. I'm reading that diammonium phosphate can raise pH. Is this a possibility? I'm adding a tsp with 5 minutes left in the boil.

 

[HopSing]

Doubt the yeast nutrient will do it, but give your pH meter a workout on your next batch. Keep the samples and record what the reading was for each sample. Retest the samples and confirm the reading did not change over time. This will rule out a faulty meter. Also what's the temp of the samples? I believe higher temps will show a lower pH, but it's another variable to watch.

~HopSing.

 

[VikeMan]

I did not measure my sparge water pH. It's just distilled water. But I am treating it with some gypsum, calcium chloride, epsom salt, and canning salt. Perhaps I'll test this next time as you suggest.

You won't really be able to get a reliable pH reading of that sparge water by itself. But there's nothing in it that would increase your overall pH.

 

[Bobo1898]

Also what's the temp of the samples? I believe higher temps will show a lower pH, but it's another variable to watch.

Mash samples are around 80. Post boil sample was 69.

 

[mac_1103]

Bru'n Water tells me to add 0.01ml of lactic acid to my sparge water. I'm not quite sure how to measure this

Dilute your lactic acid 1:100 and add 1 mL.

 

[VikeMan]

One thing is, I build up from distilled water and Bru'n Water tells me to add 0.01ml of lactic acid to my sparge water. I'm not quite sure how to measure this so I forgo this acid addition because it's so small. But I doubt it would be the cause of why my pH would be so high. But it made me think that maybe I do need to add lactic acid to my sparge---half the amount of what I add to the mash or something?

You don't need to add any acid to sparge water that you build from distilled, unless you add something with buffering capacity (like baking soda or slaked lime), which you didn't. The sparge water you used won't measurably change the pH of your mash/wort.