Mash pH not as predicted

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My tap water here is very hard: 15.7 dKH, or 342ppm as bicarbonate, so I have to treat it with acid. I use Bru'n Water or Brewer's Friend to calculate the amount.
Recently I had some efficiency issues that I thought might be pH-related so I thought I'd check the predictions of the tools. The results seem to be a lot less accurate than I expected.

I tested four 'mini-mashes' of 20g Warminster MO (EBC 7) in a 40min single infusion at 66ºC with 3l/kg of tap water treated with different amounts of CRS.

CRS added (ml/l)measured pH (cooled sample)predicted pH (Bru'n Water)predicted pH (Brewer's Friend)gravity
0.006.056.275.71.073
1.505.655.385.31.075
1.755.615.235.241.075
2.005.545.095.171.074

  • tap water alkalinity was measured with a Salifert KH kit
  • pH readings were taken at 25ºC with a freshly-calibrated pH meter
  • CRS strength was checked with the Salifert kit: 1.22 ml/l reduced the alkalinity as CaCO3 by 230ppm (2% higher than the spec sheet)
  • water was treated in batches of 500ml which were then left to stand for 30mins before use
  • the mashes were heated together in a water-bath to ensure consistent temperatures, and stirred regularly

Does anyone else get errors of this kind of size?
I'm wondering if it's strange batch of malt... looking at the SG (final column) the extract efficiency seems to be OK though.
I think I'm using the tools correctly (for example here's a link to the BF sheet for the 2.0 ml/l mash) but if anyone can see anything obviously wrong then please shout.

Screenshot 2022-04-21 at 09.32.51.png
 
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The water calculators will all agree on the salt ion concentrations because that's dealing with solid mathematical certainties. But shift to pH predictions, well that's taking a trip to the world of Narnia! Both Bru'n Water and Brewer's Friend are based on fairly old model's so they're not surprisingly similar. I was using "Mash-made-easy" which uses fairly recent prediction models (I think he's still tweaking them) and the developer pops up here from time-to-time: MashMadeEasy (it's free!).

My water supplier recently messed with their dosing system. pH became "unpredictable", and I now use Bru'n Water (results still overestimate, but is closer ... for now). I've very soft water, sneeze and the pH changes several points. MashMadeEasy is currently tending to overestimate a lot so might be just right for you? Give it a go? Basically, if pH predictions from a water calculator isn't working, change the water calculator! There's no overall right or wrong, just what's right for you is very wrong for someone else.

[EDIT: Beersmith and CRS/AMS]
 
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The water calculators will all agree on the salt ion concentrations because that's dealing with solid mathematical certainties. But shift to pH predictions, well that's taking a trip to the world of Narnia! Both Bru'n Water and Brewer's Friend are based on fairly old model's so they're not surprisingly similar. I was using "Mash-made-easy" which uses fairly recent prediction models (I think he's still tweaking them) and the developer pops up here from time-to-time: MashMadeEasy (it's free!).

My water supplier recently messed with their dosing system. pH became "unpredictable", and I now use Bru'n Water (results still overestimate, but is closer ... for now). I've very soft water, sneeze and the pH changes several points. MashMadeEasy is currently tending to overestimate a lot so might be just right for you? Give it a go? Basically, if pH predictions from a water calculator isn't working, change the water calculator! There's no overall right or wrong, just what's right for you is very wrong for someone else.

[EDIT: Beersmith and CRS/AMS]
Brilliant - many thanks for the tip athumb..
 
Careful though. The "brilliant" bit of my answer is the last statement, which effectively shoots down any competitive answer before it's written!
Heh - I like pre-emptive strike ;-)
Just trying MashMadeEasy. On the Source Water Analysis sheet, when it asks for 'Alkalinity' as mg/l what does it want... permanent hardness as CaCO3, as HCO3, total hardness as CaCO3, or unicorns per square kilometre?

EDIT: by playing around I think it wants ppm as CaCO3, otherwise the ions don't balance
 
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Heh - I like pre-emptive strike ;-)
Just trying MashMadeEasy. On the Source Water Analysis sheet, when it asks for 'Alkalinity' as mg/l what does it want... permanent hardness as CaCO3, as HCO3, total hardness as CaCO3, or unicorns per square kilometre?
"Alkalinity" is effectively temporary hardness (bicarbonate) in UK tap water (other sources of "alkalinity" are irrelevant in such cases - bet someone comes up with one now!). There are loads of conversion tables on the Int'net.

Don't forget "as" isn't the same as "is"!
 
There was a "pre-emptive strike" lurking in that last reply of mine too. "Alkalinity" the same as "temporary hardness" ... eh? In tap water it is. Consider the popular "alkalinity" test:

Salifert Carbonate Hardness & Alkalinity (Kh/Alk) Test Kit, 100-200 Tests : Amazon.co.uk: Pet Supplies

Forumites will like to contradict me, but contradict their favorite alkalinity tester too? A sure way of increasing "alkalinity" is add a load of Lye (caustic soda). Fortunately, we don't get a lot of that in tap water! There's a lot more to be found on "alkalinity" from the aquarium bunch because getting it wrong for us brewers might result in slightly sub-prime beer whereas getting wrong for aquarium lovers will result in all their fish dying. E.G. 4.5.2. Carbonate Hardness (aquariumscience.org). We might adjust "alkalinity" with calcium hydroxide (lime) though.

"Alkalinity" affects how easily you can change pH (generally; easy for soft water, difficult for hard water).
 
Brewers friend predictor has always been way out for so just go by own notes now. Tried using RO water for time recently so having now previous days gave brewers friend another go. Ended up 4.8 ph.
 
seemingly impenetrable terminology floating around the topic.

That about sums it up for me too. I like your sampling, I'd be curious if you went over board and added 3ml/l if it would take it down as much as the calcs say.

I will try to run this through beersmith later, he added some additional formulas for mash pH. I am curious to see if they match up.
 
I wonder if more of the variability in pH comes from the malt itself, being a natural product the amounts of phosphates will probably vary significantly. My water alkalinity tested by salifert is remarkably consistent, so it must be the main variable right.

I'd anticipate large swings in the pH due to any variabily if you have reduced alkalinity to very low levels, as there's nothing to buffer.
 
The water calculators will all agree on the salt ion concentrations because that's dealing with solid mathematical certainties. But shift to pH predictions, well that's taking a trip to the world of Narnia! Both Bru'n Water and Brewer's Friend are based on fairly old model's so they're not surprisingly similar. I was using "Mash-made-easy" which uses fairly recent prediction models (I think he's still tweaking them) and the developer pops up here from time-to-time: MashMadeEasy (it's free!).

My water supplier recently messed with their dosing system. pH became "unpredictable", and I now use Bru'n Water (results still overestimate, but is closer ... for now). I've very soft water, sneeze and the pH changes several points. MashMadeEasy is currently tending to overestimate a lot so might be just right for you? Give it a go? Basically, if pH predictions from a water calculator isn't working, change the water calculator! There's no overall right or wrong, just what's right for you is very wrong for someone else.

[EDIT: Beersmith and CRS/AMS]

Exactly the same with me. Apps all overestimate how much acid I need to hit mash pH.
 
I wonder if more of the variability in pH comes from the malt itself, being a natural product the amounts of phosphates will probably vary significantly. My water alkalinity tested by salifert is remarkably consistent, so it must be the main variable right.

I'd anticipate large swings in the pH due to any variabily if you have reduced alkalinity to very low levels, as there's nothing to buffer.

That's an interesting point, and one that probably isn't considered enough (in all aspects of brewing).
 
I'd be curious if you went over board and added 3ml/l if it would take it down as much as the calcs say.
Well on my next brew I shall probably find out - I am now mashing in at about 55ºC so that I can do what Braukaiser calls the 'no rush pH adjustment': making any necessary adjustments to pH before reaching the enzyme activity zone.

I will try to run this through beersmith later, he added some additional formulas for mash pH. I am curious to see if they match up.
That would be brilliant thanks athumb.. If the tool wants the parameters for my tap water, the Affinity Water report says Ca 126, Na 19, Mg ??, chloride 31-44, nitrate 22-27, sulphate 18-31 and alkalinity (as HCO3) 333. I've just sent off a sample of my water to the redoubtable Neil at Phoenix Analytic so hopefully I will soon have some rather more concrete numbers...
 
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