[jc24]

I use RO water for brewing, and my TDS reading tells me it's at 10ppm. I use the Bru'n Water spreadsheet, carefully weigh and add my additions, and yet all of my brews using my adjusted RO water have been about 0.7pH too high. Any ideas? On the Water Adjustment page, I set the dilution water percentage to 100%, select RO water as the dilution water. I find I have to add about 7 - 7.5ml of 88% lactic acid to my mash water to get it where I want it.

The first thing that comes to mind is that my pH meter is lying to me. I calibrate it before use, and it's new, but a cheap Chinese knockoff - this is the one https://www.ebay.com.au/itm/Portable-Digital-PH-Tester-Meter-Pen-Thermometer-Kit-Waterproof-0-1-CT-6021A/272945913272?rt=nc&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D20151029142714%26meid%3D828932ecf15844d8858479df3b84ccff%26pid%3D100005%26rk%3D5%26rkt%3D6%26sd%3D321746376212&_trksid=p2047675.c100005.m1851 I would be surprised if it was this inaccurate though - a pH of 0.7 off is a huge difference.

[tommymorris]

Do you calibrate the pH meter before use?

[jc24]

Yes.

[tommymorris]

Yes.

Sorry. I missed that on the first read. I will leave this to people with more expertise. The good news is that Brunwater likely put you where you needed to be.

[jc24]

In a roundabout way, yes! I've learned that if I adjust things so it predicts a pH of 5.2 with no acid additions, then to ACTUALLY hit a mash pH of 5.2, I need to add around 7 - 7.5ml of 88% lactic acid.

[hopfenundmalz]

In a roundabout way, yes! I've learned that if I adjust things so it predicts a pH of 5.2 with no acid additions, then to ACTUALLY hit a mash pH of 5.2, I need to add around 7 - 7.5ml of 88% lactic acid.

It calibrates, but the pH is off on the high side. Does that happen for all styles?

[jc24]

In a roundabout way, yes! I've learned that if I adjust things so it predicts a pH of 5.2 with no acid additions, then to ACTUALLY hit a mash pH of 5.2, I need to add around 7 - 7.5ml of 88% lactic acid.

It calibrates, but the pH is off on the high side. Does that happen for all styles?

Not sure yet, I've only been measuring mash pH for 5 brews so far - 2 IPAs, an APA, Belgian Wit and a Dusseldorf Alt. All of them read around 0.7 higher than what Bru'n Water predicted. I'm confused! To get the spreadsheet to align with my readings, I have to tell it my water has 250ppm bicarbonate which is of course impossible, given that my TDS are at 10ppm.

[hopfenundmalz]

In a roundabout way, yes! I've learned that if I adjust things so it predicts a pH of 5.2 with no acid additions, then to ACTUALLY hit a mash pH of 5.2, I need to add around 7 - 7.5ml of 88% lactic acid.

It calibrates, but the pH is off on the high side. Does that happen for all styles?

Not sure yet, I've only been measuring mash pH for 5 brews so far - 2 IPAs, an APA, Belgian Wit and a Dusseldorf Alt. All of them read around 0.7 higher than what Bru'n Water predicted. I'm confused! To get the spreadsheet to align with my readings, I have to tell it my water has 250ppm bicarbonate which is of course impossible, given that my TDS are at 10ppm.

Hopefully Martin will comment soon.

[kramerog]

Don't know if this would change anything, but perhaps you should use RO as your main source of water rather than as your source of dilution water.  There are threads on this board about what to do when RO is your main source of water and you haven't had your RO analyzed.

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[The Beerery]

Your basemalt could have a higher pH than the bruwater sheet has for the malt.

[coolman26]

Your basemalt could have a higher pH than the bruwater sheet has for the malt.

Beat me to it, what is the base Malt you are using?  Is it the same base for all of your brews?  I’ve had ph issues before when using Best. Switched to Weyermann and I’ve never had an issue since.
Brew’n water has been really accurate for me.


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[hopfenundmalz]

Your basemalt could have a higher pH than the bruwater sheet has for the malt.

Beat me to it, what is the base Malt you are using?  Is it the same base for all of your brews?  I’ve had ph issues before when using Best. Switched to Weyermann and I’ve never had an issue since.
Brew’n water has been really accurate for me.


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My problem with Best was that it was too low.

jc24, do a mini mash with your basemalt in distilled water, see what the pH is.

[coolman26]

Your basemalt could have a higher pH than the bruwater sheet has for the malt.

Beat me to it, what is the base Malt you are using?  Is it the same base for all of your brews?  I’ve had ph issues before when using Best. Switched to Weyermann and I’ve never had an issue since.
Brew’n water has been really accurate for me.


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My problem with Best was that it was too low.

jc24, do a mini mash with your basemalt in distilled water, see what the pH is.

Being low was my issue too, point being, you have to do exactly that. Do a mash and you know.


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[mabrungard]

A systematic deviation of 0.7 units across a variety of styles suggests that the instrument is faulty. I can believe an error of 0.1 to 0.2 units when using Bru'n Water since its only as good as the input data and brewing material characteristics. I haven't seen a case where the data or materials differed that greatly to produce a pH difference as high as mentioned.

Anything is possible, but this difference doesn't agree with results I've seen and heard of over the years. I strongly recommend that you find or borrow another calibrated meter to check your results.

[jc24]

Thank you for the replies everyone. I used 3 different base malts for the brews I mentioned - Simpson's Maris Otter, Barrett Burston's Pale Ale and Weyermann's Pilsner. I shall do a mini mash with distilled water as suggested and see what reading I get. I'll have to wait for a while though as I've run out of calibrating solutions - have ordered more so hopefully I'll be able to do this test soon.

And yes, the easiest thing to do would be to borrow someone else's reliable pH meter - I'll see what I can do!

Thanks again - I'll report back here once I've had a chance to follow up on your suggestions.