The Impacts Of A Low Mash Ph

[bear09]

Hi All.

I am brewing again after some 14 odd months and I am bloody happy about it.

Eveything on brew day went well except for the mash. I measured the PH 5 mins into the mash and noticied it to be 4.18 which I was dissapointed about. There were no dark grains in the mash - it was basically all maris otter.

Does anyone know what the potential ramifications of such a low mash PH are? I had a look through 'how to brew' but could not find this.

Also, what salts/chemicals can I add to the mash to raise the PH? I know that salts like gypsum can lower the PH but I dont know how to raise it. Any advice would be much appreciated. (I TRIED TO USE THE SEARCH FEATURES BUT 'PH' IS NOT A LONG ENOUGH WORD TO SEARCH ON.)

Cheers.

 

[hockadays]

Ph is tricky to search for. Have you calibrated your meter? Also what water did you use? Just MO should not drop ph that much with just tap water. Also calcium carbonate is whatbyou need ton add which I think is chalk.

 

[RdeVjun]

At mash temperatures the pH will be about 0.35 pH units lower than the equivalent room temperature solution, that would make much of the ground up. Is your measurement temperature- corrected?

 

[bear09]

Ph is tricky to search for. Have you calibrated your meter? Also what water did you use? Just MO should not drop ph that much with just tap water. Also calcium carbonate is whatbyou need ton add which I think is chalk.

Hi there - thanks for the speedy response.

I did calibrate the PH meter and I was using tap water (Craigieburn victoria - soft as butter on a hot day).

I agree it should not have dropped that much. PH of my water out of the tap is about 5.8 I think.

Calcium carbonate - gotcha - thanks.

 

[bear09]

At mash temperatures the pH will be about 0.35 pH units lower than the equivalent room temperature solution, that would make much of the ground up. Is your measurement temperature- corrected?

NO - it is not. This is another interesting point.

Perhaps I was not as far off the mark as I thought...

Another question - how long do the probes last on PH meters???

 

[RdeVjun]

Its not really a case of how long your pH probe will last, it is really about how long it will remain within specification (i.e. continues to calibrate OK). Once it fails to calibrate, there's your answer!
Some handheld probes (TPS mostly) we've had at work fail at day 1 and go straight back (quite unusual), however most are many years old, but we're only measuring environmental waters at room temperature and in the field, so not quite as hostile as mash.

Hope this helps, good luck with it! :icon_cheers:

 

[bear09]

Its not really a case of how long your pH probe will last, it is really about how long it will remain within specification (i.e. continues to calibrate OK). Once it fails to calibrate, there's your answer!
Some handheld probes (TPS mostly) we've had at work fail at day 1 and go straight back (quite unusual), however most are many years old, but we're only measuring environmental waters at room temperature and in the field, so not quite as hostile as mash.

Hope this helps, good luck with it! :icon_cheers:

How often should I need to calibrate it? I have only calibrated it a couple of times since I bought it. I just dip it in the PH 4.0 and turn the screw until it reads 4.0.

 

[RdeVjun]

Some brewers calibrate pH every time they use it, i.e. before every session (I'd recommend that), which may be say once a week. We tend to calibrate them daily when they're in use all the time, but we'll calibrate every sensor before field work theoretically every day, but practically every few days as we prefer to do it in a constant temperature room. pH isn't a parameter we have much of an interest in though, its mainly ionic chemistry, CFCs and stable isotopes that we're doing.
In the long run it should pay to keep an eye on your standard solution, dipping the probe in the whole bottle probably isn't recommended but you'll get away with it for a while. We do what most manufacturers suggest and decant some into a small tube then toss it when we're done, but that may not always be practical but you can have confidence that the standard isn't corrupted.
BTW, I'm not having a go, just some suggestions to think about, I know how it is with standard solutions, they're a PITA!

 

[bear09]

Anyone able to answer my initial query about the impacts of a low mash PH on the finished beer?

Thank you.

 

[wessmith]

Its unlikely that you have correct pH reading if you say your tap water is below 6.0. At that low figure all sorts of issues would develop in the metro water system. By law, water should be between 7.0 and 8.0pH roughly speaking. I would be getting a cross check on your pH meter.

Wes

Anyone able to answer my initial query about the impacts of a low mash PH on the finished beer?

Thank you.

 

[wessmith]

Just noticed this comment - you should be calibrating at pH7.0, not 4.0.

Wes

How often should I need to calibrate it? I have only calibrated it a couple of times since I bought it. I just dip it in the PH 4.0 and turn the screw until it reads 4.0.

 

[hockadays]

Your efficiency would suffer with a Ph that low and there maybe problems with IBU 's in your final wort, but I'm tipping your reading is incorrect and your beer will be fine.

 

[bear09]

Just noticed this comment - you should be calibrating at pH7.0, not 4.0.

Wes

My caliberation solution is PH4.0. Should I be getting some PH7.0 from somewhere?

 

[RdeVjun]

My caliberation solution is PH4.0. Should I be getting some PH7.0 from somewhere?

There's various pH standard solutions available, 4.0, 7.0, 10.0, 6.something etc., for calibration/ checking performance of pH meters. There may be some benefit in doing two point calibration (or more than two- point, but as a home brewer you'd probably be pointy- headed if you did!), but if your meter is an 'adjust the dial' type, you won't be doing that as multi- point calibrations are for digital meters. 4.0 or 7.0 would cover the bases fairly well, we're looking at 5.something as the normal range.
I'd keep doing what you're doing, but let a sample of wort cool to room temperature BEFORE placing the probe in it. You could speed this up in an ice bath if need be.

 

[brando]

Reading this thread makes me think that I'm getting a false reading by just dipping my pH strips into the mash (at say 66 degrees). Is that right? Out by 0.35 (lower)?

I assume the right way to measure mash pH is to take a sample from the mash and let it rise to room temp first, then take the reading.

I wonder how far into the mash is the right time to measure pH? I normally take the reading after 30 mins when I remove the sleeping bag from the urn and stir (BIAB).

 

[RdeVjun]

Good questions Brando!

I'm not sure about test strips, I haven't used them in this situation, more digital pH meters with a probe, but I would be inclined to do the same as I recommended above so take a small sample, cool it and then dip the strip. Mind you other brewers may have other opinions on this and I'll happily stand corrected.

As far as when is the right time, you're hoping to achieve a particular pH for the whole mash, so earlier rather than later. Braukaiser should help, its a fairly heavy read, however it is very worthwhile. If you're doing the same or a similar recipe again and again, it is possible to achieve the target pH by adjusting salts and additions, if need be that is.

FWIW, I don't actually do much in the way of actual pH adjustment and if you're already getting good results then don't change anything. It is more likely to be problematic where your source water is alkaline like where I live, but I use rainwater anyway and just add salts to suit the style.

 

[Kai]

One other thing nobody as mentioned, but still relating to the pH meter. I'd be very surprised if you actually had a mash pH of 4.18. That's pretty damned low.

Let us know how the final beer turns out!

 

[MitchDudarko]

Maybe for ease of searching in future PH related topics should be titled 'PEE HAICH'??

 

[felten]

I guess it depends on the pH strips you use, I'm using the pehanon strips from grain and grape (down the bottom of the page here), I've tested them side by side in mash temp and room temp wort and the reading has remained the same. Unfortunately I've been out of strips for my last 2 brews so I can't do any more testing but I'd be confident enough to take the reading straight from the mash.

BTW you can cut those strips into 2, or if you're a cheap bastard like me into thirds, and get more bang for your buck.

Reading this thread makes me think that I'm getting a false reading by just dipping my pH strips into the mash (at say 66 degrees). Is that right? Out by 0.35 (lower)?

 

[katzke]

Surprised no one has pointed out that the pH of your brewing water has Zip to do with the pH of your Mash.