How do you take a proper Mash PH reading?

[klamz]

Ever since i've started to take Mash PH readings I always had trouble getting the PH correct. It seemed like no matter how much salts I added it hardly changed. Today, I did however realize that taking a sample from the top of the mash instead of the spigot has a major difference in PH. I took a sample at the beginning of the mash from the spigot on my mash tun and the reading was 5.2 then i add some salts to get it up. After mixing it i took another sample from the spigot and it had the same reading??? Then i got curious and took a sample from the top and the reading was 5.6!?!?!? WHoooah! I think i wont be taking reading from the spigot anymore lol. Can anyone confirm that taking samples from the bottom is not accurate? Seems to me it's not

 

[wildwest450]

First, are you using a meter or strips? I recirculate my mash, so I always take a sample right from the return hose. If you stir well after adding the salts, there shouldn't be that big of a difference.

 

[klamz]

First, are you using a meter or strips? I recirculate my mash, so I always take a sample right from the return hose. If you stir well after adding the salts, there shouldn't be that big of a difference.

I'm using a meter and i mix well. After i mix i just take a tiny sample from the spigot. It was strange taking some from the top and having a huge difference

 

[weirdboy]

Why are you trying to raise the mash pH from 5.2 to 5.6?

 

[klamz]

Why are you trying to raise the mash pH from 5.2 to 5.6?

I was trying to get to 5.4 but since i was taking samples form the bottom it never changed so i didnt know what the actual PH was. So i added too much

 

[weirdboy]

What is wrong with 5.2?

I mean, I can understand if you are way high or way low, but in the range of 5.2 - 5.5, I just don't see the point of adding crap to the mash that doesn't really belong.

 

[wildwest450]

What is wrong with 5.2?

It's a tad low, the sciency guys recommend 5.4-5.6 at room temp for most beers. I shoot for 5.5 and don't sweat a few tenths either way.

 

[rockfish42]

Adding salts to adjust pH takes some time for the reaction to occur. You should be waiting 10 minutes or so to take the reading.

 

[gingerdawg]

Could there be a little liquid trapped in the spigot that doesn't mix into the mash, and then since you are taking a "tiny" sample, you're not seeing the change? Maybe you need to run an ounce or two through the spigot and then check?

 

[MNDan]

I wouldn't take samples from the spigot if you are adjusting with salts. Actually, I'd never adjust with salts during the mash - too hard to diffuse them properly. Use the below, take measurements, and adjust from batch to batch.

https://www.homebrewtalk.com/f128/brewing-water-chemistry-primer-198460/

https://www.homebrewtalk.com/f128/ez-water-calculator-3-0-a-261001/

 

[shataway]

I've seen a difference between the spigot and the top after waiting 10 min after dough in. I stir as i dough in and after 10 min I run a couple of quarts thru the spigot to flush it out. A .2 - .3 difference if I remember correctly. Also, at end of the mash and vorlauf, I will take another sample and it is closer to the original spigot reading.

 

[klamz]

I've seen a difference between the spigot and the top after waiting 10 min after dough in. I stir as i dough in and after 10 min I run a couple of quarts thru the spigot to flush it out. A .2 - .3 difference if I remember correctly. Also, at end of the mash and vorlauf, I will take another sample and it is closer to the original spigot reading.

So you recommend letting a couple of quarts flush out before taking any readings?

 

[shataway]

So you recommend letting a couple of quarts flush out before taking any readings?

Sure.

If you really want to do some investigation into ph measurement, consider the following sample method. Wait 10 minutes after dough in and take a sample from the top and set it aside. Run a couple of quarts thru the spigot and take a sample. Compare the ph after cooling both to room temp. After the mash is done and you have vorlaufed, take samples from the beginning, middle, and end of the first runnings. Compare the ph after cooling them to room temp.

I am brewing a Scottish ale this weekend and will try to do the same.

 

[klamz]

Sure.

If you really want to do some investigation into ph measurement, consider the following sample method. Wait 10 minutes after dough in and take a sample from the top and set it aside. Run a couple of quarts thru the spigot and take a sample. Compare the ph after cooling both to room temp. After the mash is done and you have vorlaufed, take samples from the beginning, middle, and end of the first runnings. Compare the ph after cooling them to room temp.

I am brewing a Scottish ale this weekend and will try to do the same.

But wait, by the time you took the samples and wait for them to cool it would be too late to change the mash ph since the mash more than likely finished converting already. Doesn't it have to mash at 5.4 the whole time? This is what confuses me. it takes too long to adjust the PH before the conversion is complete. Between taking samples and adding salts and mixing 30minutes could pass before you hit the PH. But please when you are done brewing post your findings so we can discuss

 

[rockfish42]

Isn't the main idea to know how to adjust for a subsequent batch? If you're doing everything "correctly" you should be pretty close the first time.

 

[shataway]

I have the same concerns as the OP in terms of trying to determine the correct initial ph first.

 

[shataway]

Isn't the main idea to know how to adjust for a subsequent batch? If you're doing everything "correctly" you should be pretty close the first time.

My approach is to be confident in the initial ph measurement first, make a good faith attempt at a correction in the current batch if it is really required, and try to be better next time.

 

[klamz]

I think I need my well water tested again, I heard the salt content can change rapidly causing the PH to vary from batch to batch.

 

[shataway]

Water is filtered tap water with minimal salts added to entire volume and stirred well.

Missed my mash in temp by 4 degrees. Was 4 degrees high, stirred like a madman and it was not coming down fast enough so I added ice and it came down too much. Will be mashing at 154 degrees instead of 158 degrees.

After 10 minutes, I took a sample from the top and strained it through a filter to remove most of the grain bits. I took a sample from the spigot after running a couple of quarts through it. The top was 5.26 and the spigot was 5.23 after cooling to room temp. Maybe I had not been stirring enough in previous batches because my temp was alread good? Go figure. Going to let this ride at 5.2something.

End of Mash EDIT: After vorlauf, 21brix, ph is 5.08. Oh well. Missed the other two data points since I was inside cooling the first sample and the runoff was much quicker. Going to have to call this batch "4 strikes" at this point.

End of single batch sparge EDIT: After vorlauf 7brix, ph is 5.31.

End of boil, into fermentor EDIT: ph 5.15

Final error count = "6 strikes" as I did not add the Immersion Chiller and whirlfloc with 15 minutes to go. I lost track of time since I did not have any late hop additions. On the bright side, I did not have any hop aroma/taste to boil away by boiling 10 minutes longer. Time to have a cold one...

 

[klamz]

Water is filtered tap water with minimal salts added to entire volume and stirred well.

Missed my mash in temp by 4 degrees. Was 4 degrees high, stirred like a madman and it was not coming down fast enough so I added ice and it came down too much. Will be mashing at 154 degrees instead of 158 degrees.

After 10 minutes, I took a sample from the top and strained it through a filter to remove most of the grain bits. I took a sample from the spigot after running a couple of quarts through it. The top was 5.26 and the spigot was 5.23 after cooling to room temp. Maybe I had not been stirring enough in previous batches because my temp was alread good? Go figure. Going to let this ride at 5.2something.

End of Mash EDIT: After vorlauf, 21brix, ph is 5.08. Oh well. Missed the other two data points since I was inside cooling the first sample and the runoff was much quicker. Going to have to call this batch "4 strikes" at this point.

End of single batch sparge EDIT: After vorlauf 7brix, ph is 5.31.

End of boil, into fermentor EDIT: ph 5.15

Final error count = "6 strikes" as I did not add the Immersion Chiller and whirlfloc with 15 minutes to go. I lost track of time since I did not have any late hop additions. On the bright side, I did not have any hop aroma/taste to boil away by boiling 10 minutes longer. Time to have a cold one...

Thanks for the info. Very interesting. Next time I brew I will take similar notes and we will compare

 

[RM-MN]

Adding salts to adjust pH takes some time for the reaction to occur. You should be waiting 10 minutes or so to take the reading.

I'm frustrated. You need to stir well when you add the grains and this takes a little time, then since the wort is hot you take a sample and chill it to measure the pH with the meter. If you find the pH to be too high you add minerals or acid to lower the pH and stir it in well. Then you wait 10 minutes for the reaction to occur, take a new sample and let it cool to read it. Meanwhile, the enzymes don't wait and conversion can take place in as little as 15 minutes. I want my mash temperature to be 154 but when I open the lid to get a sample, I lose a degree or 2. I lose a further 4 degrees while I stir in the mineral or acid, then lose another 2 degrees when I get a new sample. Why do I even bother taking the sample and try to adjust if my wort has already converted before I can get adjustment?

 

[MichaelBrock]

I had these exact same concerns and frustrations. I asked in the water primer thread and the answer, as someone else has mentioned here, is that the idea is NOT to be adjusting during the mash but rather make measurements so that mash for subsequent brewings of the same beer can be adjusted. Unfortunately, I am some 10 beers into my all-grain experience and have yet to brew the same recipe twice. And even then, unless you're brewing that subsequent batch with the same source of grains (although I buy my 2-row in bulk, I get the specialty grains from my lhbs with each batch) you still can't make an accurate prediction of your mash pH. I also found that pH varied quite a bit from measurement to measurement in the same mash and I never trusted any of the measurements as truly representative of the mash pH.

I don't regret spending money on the pH meter but I have lost confidence that measuring pH in my situation is of any use. I just use ez water to get a rough calculation of the numbers and I start with ro/di water with ajdelange's suggested basic adjustments and don't sweat it.

 

[rockfish42]

To make matters weirder, here's a presentation from Sierra Nevada. According to this mash pH does not exactly equate to a finished product pH, it does however alter the extraction of astringency causing polyphenols.
http://www.mbaa.com/Districts/MidSouth/presentations/2010_11_12JimMellem.pdf

 

[Ma23456]

Op have you adjusted for temperature ... Ph is offset by temperature

 

[klamz]

Op have you adjusted for temperature ... Ph is offset by temperature

Yes i use the a Milwakee ph meter with temp adjustment