Why is my mash pH always way off target?

[Galena]

I never manage to hit my mash pH by a long way and I really have no idea why.
As an example my last 2 brews

Brew 1 was a Blonde Ale Target pH was 5.09, very low because I have been lowering it to see how much closer I get to a desired 5.2 to 5.4. Mash pH was actually 5.62 taken at 15 mins into the mash and measured at room temperature with an Avera pH 60

Brew 2 was a Bitter, Target pH 4.95 (even lower)- mash pH 5.52

My water profile was originally done by Phoenix Analytical (over a year ago) but I have been regularly checking using a GH and KH test kit and inputting the data into the Kaiser Water Calculator to check the numbers, there is some small variation on the Phoenix but not a lot and I adjust my profile to suit.

My water profile as taken from GH & KH today would appear to be:
Ca: 20, Mg: 5, Na: 9, Cl: 11, SO4: 29, HCO3: 43

Original Phoenix profile on 20/6/20 was:
Ca: 21, Mg: 3, Na: 9, Cl: 13, SO4: 31, HCO3:18

So the only thing of significance perhaps is the Bicarbonate level but this only appears to make 0.02 difference to the calculated pH in Brewfather. I guess the malt could be the issue but I seem to be the only one that I am aware of that has this issue.

Edit: I should add, to avoid confusion that I add the recommended salts as per Brewfather

 

[The Baron]

I use acidulated malt or Lactic acid to get my PH and although 5.2 is the sweet spot anywhere upto 5.7 is ok IMO

 

[Galena]

I use acidulated malt or Lactic acid to get my PH and although 5.2 is the sweet spot anywhere upto 5.7 is ok IMO

I use salts and lactic acid. I realise that my 5.6 is within an acceptable range but it is irking me that I cannot seem to get low, something seems to be acting as a buffer, it's as though I have a lot of Bicarbonate, which I don't.

 

[The Baron]

This one may be for the water boffins to help with then just out of curiosity how much lactic do you use in a standard brew?

 

[Galena]

This one may be for the water boffins to help with then just out of curiosity how much lactic do you use in a standard brew?

Anything up to 5mls to target 4.9 in the last brew, never added more than that, sometimes only 1 or 2 mls

 

[Hazelwood Brewery]

In case this has any relevance, I learned a lesson this last week.

I soaked my hoses in sodium percarbonate (I normally replace them when they discolour). I flushed them with clean hot water for 20 minutes but they still has a slightly milky coating on the inside. Never mind I thought, it’s a harmless salt residue.

During the mash I used those hoses to recirculate. After a while I took a pH reading assuming it would just be the usual 5.2 and it was 5.8! I immediately realised what happened, that harmless salt residue is carbonate!

Long story but if you happen to use sodium percarbonate in your cleaning regime…

 

[The Baron]

That seems a ok amount I use 6ml of lactic or 175g of acid malt to get to 5.2 to 5.4.
It does sound as if something else is stopping the PH dropping to where you want it.Lets see if the water techs can come up with some ideas

 

[Galena]

Long story but if you happen to use sodium percarbonate in your cleaning regime…

Well, not that long really
It's a good point and something I bet not many consider although I have been using VWP to clean my hoses and then pump clean water through but I have beem meaning to swap over to sodium percarbonate so will be something to be aware of.

 

[Sadfield]

Not enough calcium, you should have 50-150ppm. Calcium reacts with malt phosphates to release hydrogen ions which lowers the mash pH.
https://www.google.com/amp/s/www.mu...echnical-articles/water-water-everywhere/amp/

 

[Cptn_Needa]

Your measurments of 5.62, was that on the PH meter or temperature corrected value?

 

[Galena]

Not enough calcium, you should have 50-150ppm. Calcium reacts with malt phosphates to release hydrogen ions which lowers the mash pH.
https://www.google.com/amp/s/www.mu...echnical-articles/water-water-everywhere/amp/

I'm not sure what you mean? I always add either CaCl or Gypsum to increase calcium, Brew 1 had a calculated calcium content of 92ppm and Brew 2 149ppm

 

[Galena]

Your measurments of 5.62, was that on the PH meter or temperature corrected value?

That was on the pH meter measured at room temperature

 

[Sadfield]

I'm not sure what you mean? I always add either CaCl or Gypsum to increase calcium, Brew 1 had a calculated calcium content of 92ppm and Brew 2 149ppm

Sorry, for not knowing that.

 

[Galena]

Sorry, for not knowing that.

Sorry, I guess my OP didn't explain that, my mistake and now edited

 

[Ben034]

I never manage to hit my mash pH by a long way and I really have no idea why.
As an example my last 2 brews

Brew 1 was a Blonde Ale Target pH was 5.09, very low because I have been lowering it to see how much closer I get to a desired 5.2 to 5.4. Mash pH was actually 5.62 taken at 15 mins into the mash and measured at room temperature with an Avera pH 60

Brew 2 was a Bitter, Target pH 4.95 (even lower)- mash pH 5.52

My water profile was originally done by Phoenix Analytical (over a year ago) but I have been regularly checking using a GH and KH test kit and inputting the data into the Kaiser Water Calculator to check the numbers, there is some small variation on the Phoenix but not a lot and I adjust my profile to suit.

My water profile as taken from GH & KH today would appear to be:
Ca: 20, Mg: 5, Na: 9, Cl: 11, SO4: 29, HCO3: 43

Original Phoenix profile on 20/6/20 was:
Ca: 21, Mg: 3, Na: 9, Cl: 13, SO4: 31, HCO3:18

So the only thing of significance perhaps is the Bicarbonate level but this only appears to make 0.02 difference to the calculated pH in Brewfather. I guess the malt could be the issue but I seem to be the only one that I am aware of that has this issue.

Edit: I should add, to avoid confusion that I add the recommended salts as per Brewfather

Assuming your pH meter is calibrated?

 

[Galena]

Assuming your pH meter is calibrated?

Yes, absolutely

 

[Cptn_Needa]

That was on the pH meter measured at room temperature

My understanding from reading Gordon Strong is that the target PH is at mash temp but most meters need to take readings at room temp.
PH changes over temp and its about +0.3 at 20C compared to 65C.

So your actual PH you are at is not 5.62 it's more like 5.32.

Still not where you want to be but closer.

I fully expect to have this post corrected by someone who knows better (I'm still very much learning about water ph)

 

[Ben034]

What's your mash thickness? I'm always a bit off (high) as I do a thin mash (full volume BIAB). I then usually add a little additional acid after 15 mins and usually get there. Strange though if you're already aiming low and adding additional acid to compensate

 

[Galena]

What's your mash thickness? I'm always a bit off (high) as I do a thin mash (full volume BIAB). I then usually add a little additional acid after 15 mins and usually get there. Strange though if you're already aiming low and adding additional acid to compensate

3:1 Water to grist ratio

 

[Galena]

My understanding from reading Gordon Strong is that the target PH is at mash temp but most meters need to take readings at room temp.
PH changes over temp and its about +0.3 at 20C compared to 65C.

So your actual PH you are at is not 5.62 it's more like 5.32.

Still not where you want to be but closer.

I fully expect to have this post corrected by someone who knows better (I'm still very much learning about water ph)

I have spent quite a bit of time researching this, and I will let somebody better qualified say:
But none of this matters since by convention pH values in brewing are reported as the pH of a room temperature sample. This arises from the laboratory practice of cooling pH samples before pH is tested. While pH meters can correct for temperature and their probes may be able to withstand higher sample temperatures, testing only cooled sample extends the life of the probe. This common practice also means that reported pH optima and pH ranges are for room temperature samples even though the actual reaction happens at higher temperatures.