mash pH was 1 point lower than spredsheet estimated

[JETDOG07]

I used 11.4 pounds of pilsner and 1.1 pounds of white wheat for this mash. I use Kai's spreadsheet and distilled water to figure out my water additions. According to the spreadsheet with a 4 gallon mash and 3.7g CaSO4 3.4g CaCl 1g of baking soda, 2.7g of Epsom Salt and 6 mL of lactic acid, I should have hit a mash pH of 5.2 at room temp. When I took my measurement I got a reading of 4.4 three times in a row.

I have used this spreadsheet for my last 4 brews and hit the estimated mash pH right on the nose. Any thoughts on why this was so far off? Also mashed at 147F for an hour.

 

[tmendick]

Did you take a pH reading of the water itself? I've found that sometimes my pH meter doesn't accurately measure plain RO or distilled water.

 

[JETDOG07]

Did you take a pH reading of the water itself? I've found that sometimes my pH meter doesn't accurately measure plain RO or distilled water.

No, I was only testing the pH of the mash after about 10 minutes of mashing.

 

[mabrungard]

Why are you adding baking soda and lactic acid? They counteract each other.

 

[bierhaus15]

Why are you adding baking soda and lactic acid?

6ml of lactic in a 5 gallon batch is a lot, especially if you're using distilled.

 

[JETDOG07]

Why are you adding baking soda and lactic acid? They counteract each other.

Baking soda to get some Sodium and then acid to get the pH down to the value I needed. And I thought 6 mL seemed like a lot too, but that's what the spreadsheet said would get me to 5.2

 

[JETDOG07]

Also in my last beer that was a wheat beer I used 5 mL of acid and hit my 5.3 pH target. Just trying to figure out why this one went so low.

 

[Silver_Is_Money]

The 1 gram of added baking soda knocked out roughly 1 mL of your 6 mL's of 88% lactic acid, so effectively you added closer to 5 mL's of acid. With Pilsner malt plus wheat I'd be hard pressed to envision it falling below 5.25-5.30 pH during the mash (even when considering that your mineralization seems a bit on the high side). 4.4 pH is radically low, and not believable.

Did you hit your anticipated OG? Is it fermenting normally?

 

[JETDOG07]

I actually only got 60% mash efficiency when I calculated the recipe for 70%. It went from 1.051 to 1.005 overnight. I used glucoamylase and hornindal kveik yeast which is a known fast fermenter. I thought the 4.4 was not believable either but I took 3 separate mash samples and they all read the same.

I also added 1.2 g of pickling lime and that brought the readings back up to 5.2.

Also on the high mineralization, I made a brut IPA and wanted 100 ppm SO4 to 50 ppm Chloride

 

[mabrungard]

Low mashing pH does increase proteolysis and that makes the wort more fermentable and it also reduces beer body. I caution against taking mashing pH too low.

 

[JETDOG07]

Low mashing pH does increase proteolysis and that makes the wort more fermentable and it also reduces beer body. I caution against taking mashing pH too low.

Right, I corrected the pH back up with pickling lime about 15 minutes into the mash. I'm more concerned how it got that low. I don't believe 6 mL of lactic acid should have taken it that low. I guess my pH meter could have malfunctioned maybe? I just calibrated it so I don't think that's likely.

 

[Silver_Is_Money]

It may have more likely required in the neighborhood of 5 to 7 grams of slaked lime to move a 4.4 pH mash to 5.2 pH, as opposed to the 1.2 grams you added. You might have actually gotten it down to about 5.0 to 5.1 pH before the 1.2 g. slaked lime addition. My first thought is that after you added the lactic acid you may not have mixed it sufficiently well or given it sufficient time before pulling the sample that indicated 4.4 pH, resulting in a false low pH reading.

How carefully did you measure the 6 mL lactic acid addition?

 

[JETDOG07]

It may have more likely required in the neighborhood of 7 grams of slaked lime to move a 4.4 pH mash to 5.2 pH, as opposed to the 1.2 grams you added. You might have actually gotten it down to about 5.0 to 5.1 pH before the 1.2 g. slaked lime addition. My first thought is that after you added the lactic acid you may not have mixed it sufficiently well or given it sufficient time before pulling the sample that indicated 4.4 pH, resulting in a false low pH reading.

How carefully did you measure the 6 mL lactic acid addition?

Used a 1 mL syringe. I put all my salts and acid in my mash water as it's heating to strike temperature. I stirred the mash for about 5 minutes then let it sit for 5 minutes and pulled my sample.

 

[ajdelange]

I used 11.4 pounds of pilsner and 1.1 pounds of white wheat for this mash. I use Kai's spreadsheet and distilled water to figure out my water additions. According to the spreadsheet with a 4 gallon mash and 3.7g CaSO4 3.4g CaCl 1g of baking soda, 2.7g of Epsom Salt and 6 mL of lactic acid, I should have hit a mash pH of 5.2 at room temp. When I took my measurement I got a reading of 4.4 three times in a row.

Kai's spreadsheet is pretty good so I'm a little surprised that it predicted a pH as low as 5.2. I couple of tenths higher seems more reasonable. But in any case 4.4 is absurd. So how did you get this?

When a pH reading is so far off I always suspect the meter (or it's calibration). Because of this the first thing to do if you get a wild reading like this is to rinse the probe and put it back in the pH 4 buffer. Did you do this? What did it read? Was the meter recently (as in within a half hour or so) calibrated? With fresh buffers? Has it passed the stability check? Recently?

No, I was only testing the pH of the mash after about 10 minutes of mashing.

When one checks a mash made using liquor to which acid has been added initial readings are often startlingly low because you are really measuring, at that point, the acidified water as the reactions that neutralize the acid are just getting underway. But the pH generally rises pretty quickly and though it may continue to rise well past 10 minutes I would not expect it to be so much lower than the estimated equilibrium pH (be it 5.2 or 5.4) at the 10 minute point.

I'd levy most of my suspicion at the pH reading. If the alibi there is good I'd suspect that more than 6 mL of lactic acid got in there somehow or that the reaction was not complete enough or that the mash wasn't well mixed and your pH sample came from a pocket of lactic acid/

 

[JETDOG07]

Kai's spreadsheet is pretty good so I'm a little surprised that it predicted a pH as low as 5.2. I couple of tenths higher seems more reasonable. But in any case 4.4 is absurd. So how did you get this?

When a pH reading is so far off I always suspect the meter (or it's calibration). Because of this the first thing to do if you get a wild reading like this is to rinse the probe and put it back in the pH 4 buffer. Did you do this? What did it read? Was the meter recently (as in within a half hour or so) calibrated? With fresh buffers? Has it passed the stability check? Recently?




When one checks a mash made using liquor to which acid has been added initial readings are often startlingly low because you are really measuring, at that point, the acidified water as the reactions that neutralize the acid are just getting underway. But the pH generally rises pretty quickly and though it may continue to rise well past 10 minutes I would not expect it to be so much lower than the estimated equilibrium pH (be it 5.2 or 5.4) at the 10 minute point.

I'd levy most of my suspicion at the pH reading. If the alibi there is good I'd suspect that more than 6 mL of lactic acid got in there somehow or that the reaction was not complete enough or that the mash wasn't well mixed and your pH sample came from a pocket of lactic acid/

I purposely added enough acid to get to the 5.2 mark. I made a brut ipa and had read mashing on the lower end is good for that.

I think you're right about the buffers. My first calibration failed but my second try calibrated in the 4.0 buffer. I'm wondering if that still causes an issue?

 

[ajdelange]

It casts the lime light on the pH reading for sure. Do not trust this meter unless you verify its calibration after every reading (pH 4 and 7). pH meters, like everything else, eventually go TU.

 

[JETDOG07]

It casts the line light on the pH reading for sure. Do not trust this meter unless you verify its calibration after every reading (pH 4 and 7). pH meters, like everything else, eventually go TU.

This is only the 3rd time I've used it and I store it in storage solution. I think my buffers may have been bad

 

[TasunkaWitko]

In the worst-case scenario, you're going to end up with beer.

 

[Blazinlow86]

This is only the 3rd time I've used it and I store it in storage solution. I think my buffers may have been bad

I had nothing but issues with my cheapy Amazon yellow ph meter. I upgraded to a better one in the 100$ range and haven't had a issue since. Not sure what your using but something to keep in mind. Cheers

 

[tmendick]

If you don't know the starting pH of the water, how could you calculate the estimated mash pH?

 

[ajdelange]

This is only the 3rd time I've used it and I store it in storage solution. I think my buffers may have been bad

While with modern technology very good meters are available in the $100 range (continue to pass on the $15 Chinese knockoffs) infant mortality is still a reality (rigors of shipping?). Any new meter should be subjected to the stability test before being put to work in brewing.

 

[ajdelange]

If you don't know the starting pH of the water, how could you calculate the estimated mash pH?

The starting pH of the water actually has little (but not nothing) to do with the source water's pH. What is much more significant is the water's carbonate alkalinity. This he has told us is 0 when he said he was using distilled water. When estimating mash pH one must take into account the proton deficit of the malts and the proton deficit of the water.The proton deficit of the water is roughly between 0.88 and 0.92 times the alkalinity which, as the alkalinity is 0, is also 0. Thus the mash pH depends only on the malts and can be calculated.

 

[tmendick]

The starting pH of the water actually has little (but not nothing) to do with the source water's pH. What is much more significant is the water's carbonate alkalinity. This he has told us is 0 when he said he was using distilled water. When estimating mash pH one must take into account the proton deficit of the malts and the proton deficit of the water.The proton deficit of the water is roughly between 0.88 and 0.92 times the alkalinity which, as the alkalinity is 0, is also 0. Thus the mash pH depends only on the malts and can be calculated.

True, I guess I don't trust that the RO/Distilled is always truly 0. I've bought many gallons of water from various sources at various times of year and my TDS meter rarely returns 0, usually its pretty low still, but I have been in the 70's all the way to 125 a few times.

You've forgotten more about water than I know, I'm not questioning your assessment, just the quality of some water labeled as distilled.

 

[ajdelange]

I'm forgetting about lots of other things too.