Low PH in mash with starting water ph of 7.5

[Patirck]

I used to have a problem with high PH and now for some reason it seems to have dropped down so much it is now too low.

I start out with filtered tap water (just a home depot cheapo carbon filter). The PH according to my calibrated meter is 7.5 (flickers between 7.4 - 7.6). I heat to strike temp and add grains then wait. About 30 minutes into the mash the PH is down to 4.6 - 4.8 @ 151*. This happened last weekend - the grain bill is 60% 2 row and 40% white wheat and it was a 5.5 gallon batch.

What effect with this have on the beer? I did get pretty bad efficiency - 56%. But that is probably at least partially due to spilling about 3/4 gallon of first runnings.

I'm guessing I need to see if this repeats iteslf with the next batch but I would like to take the guess work out of this part of the brewing process if possible. I have been getting some astringency flavors in some of my beers and I think it has to do with water chemistry. The filter helped this alot but I still get it with some batches. Most of the beer I brew are European styles that require softer water. I don't make IPAs or English styles that do well with hard water.

I live in Glendale, CA (suburban L.A.). We have our own municipal water works and I have called the water quality guy several times. He has been most helpful and even sent a crew out to do a water sample at my house. I think he doesn't get a lot of calls like mine. He tells me we now get most all of our water from the Colorado river which produces some of the hardest water around. In the past I have diluted with some ro water but I would really like to avoid that as I have a gravity system and I hate lifting big bottles of water up the ladder to pour in the hlt. I take it I would need to add something to the water to up the ph a bit (if that is really a problem).

 

[ajdelange]

It is unlikely that a beer with the grain bill you have described would go to a pH of 4.6 - 4.8 even at 151. As an aside you should not measure pH at such a high temperature as all published values (to which you will be comparing) are at room temperature and 150 will certainly shorten the life of the electrode and perhaps even damage it depending on its design.

If indeed the pH were this low (4.9 - 5.1) corrected to room temperature the beer would not be as good as it would if the mash pH were 5.4 - 5.5. You would probably get by at 5.1.

Carbon filters do not remove anything that would have an effect on the pH of your mash. Bottom line is that the pH measurement is very suspect.

 

[Patirck]

You are correct - I just checked and my PH meter is only accurate to 50c (122f). I will check it with some calibration solution and see if it still reads accurate.

How do I check the mash ph if this (very common) ph meter Hanna Instruments HI 98107 is only good to 122*?

 

[a_potter]

You should cool your sample to at least below the upper ATC range of your meter. It is best to cool to room temp. I often get mine down to 120 ish and take the ready but like Mr Delange stated you may eventually have to replace your electrode.