Sudden problems predicting mash pH

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chrisr
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Re: Sudden problems predicting mash pH

Post by chrisr » Mon Jan 14, 2019 8:09 pm

Well, I would have preferred it a bit lower, for a such a pale brew.

It's not a major worry. I just wanted to know if anyone had any explanation why the water calculators went from predicting the pH really well, to being so far out.

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orlando
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Re: Sudden problems predicting mash pH

Post by orlando » Mon Jan 14, 2019 10:46 pm

chrisr wrote:
Mon Jan 14, 2019 8:09 pm
Well, I would have preferred it a bit lower, for a such a pale brew.

It's not a major worry. I just wanted to know if anyone had any explanation why the water calculators went from predicting the pH really well, to being so far out.
Whilst you have very low alkalinity to start with I note your calcium levels are pitifully small. Apart from a whole host of other things that Calcium is good for, one of them is helping to push the mash pH into the right range. An all Pale malt mash doesn't have the acidification affects of say crystal malts or dark malts. If you can get your calcium up over 100 ppm you may find your pH to be a lot more satisfactory. As for your second question maybe there are just too many variables to control for anway but specifically, who knows. With such a wide range to target as long as you are in there somewhere don't worry. :D
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PeeBee
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Re: Sudden problems predicting mash pH

Post by PeeBee » Tue Jan 15, 2019 6:51 pm

Aleman wrote:
Sun Jan 13, 2019 12:38 pm
… A sample of the mash, taken between 10 to 15 minutes into the mash, should have a pH in the range 5.2 to 5.7. …
Taking in what you are saying, I sampled today's mash at 10 minutes: It was pH6.0! I quickly took a second sample which would have been around 20-25 minutes in: It was pH 5.5 as predicted by Bru'n Water. I was using a Grainfather which has an overflow to channel excess recirculated wort. Suggests these Grainfather type brewing systems don't reach a stable state for a longer period than just an uncirculated (but well mixed) mash, or a recirculating system (like HERMS) without such an "overflow" return path. Perhaps 15-20 minutes is a good time to wait in these "overflow" situations? This mash grain also contained slaked lime (about 0.9g, not in the water like the other salts [-X ) which would have exaggerated the slowness in attaining equilibrium too.

Also suggests: Whatever was causing me to have very low mash pH over the last year has suddenly gone away again. This is the second decent mash pH I've had recently, and no indication at all what caused it all to go wrong for the past twelve months.


I ignore the second decimal digit - reading pH to two decimal places, especially on cheap meters, is definitely a road to insanity!
Last edited by PeeBee on Thu Jan 17, 2019 12:16 pm, edited 1 time in total.
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chrisr
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Re: Sudden problems predicting mash pH

Post by chrisr » Tue Jan 15, 2019 7:44 pm

Congratulations! But I hate mysteries like these! I want to know what's going off.

My 'raw' water is very soft and has low mineral levels so I had added Calcium Sulphate and Calcium Chloride. Calcium was predicted at 157ppm. I don't think I've ever brewed with less than 100ppm Calcium..

I have a RIMS system, so the wort is constantly moving. I also made a point of spending longer than usual doughing in, and it was well mixed before I let it be.

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Re: Sudden problems predicting mash pH

Post by chrisr » Tue Jan 29, 2019 8:39 pm

Brewed again yesterday. Predicted ph 5.5 - measured 5.52.

I hope this 'winning' streak continues...

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