Strange Beer issue ( I think its pH)

So I have been relgious about pH for the last year, and have been brewing for the last 12 years. The last 5 or so religious about proper yeast pitching, fermentation temps, etc., just to give some background.

I want to see if my theory is crazy...

Previously without altering pH (using RO water and making my own water) I was making some pretty great lighter beers (specifically helles and pilsners) My regimen was big proper starters, pitch cool with 02, ferment at temp for 4 weeks rack to keg (this still remains the same).

Recently I have been noticing an off flavor to the light beers, the lighter the beer the most dominant it is. Its a slightly sour, applely flavor..I am thinking it has to do with the acid I have been working with(phosphoric, and acid malt) but more about that later. It is not beer style (ale/lager/strain) specific, but more color specific, anything under 8srm. I have a pale ale with it, a pils, and a cream ale). Here is the catch... I have a maibock on tap, brewed November, without it. So the problem has recently shown up.


Again recently I have been having huge discrepancies with Brunwater, like .3-.5. My meter (milwaukee mw-102) gets calibrated every brew session and is always spot on.

So lets outline the last brew session:

Basic lager

8lbs 2row
2lbs vienna
2lbs corn
3oz acid malt
RO water with 1tsp of cacl
According to brunwater I believe it came in at 5.2-3. After 20 minutes of the mash at 151 ( I have a herms so constant recirc) I got a ph of 5.67, Here is where I WOULD have tried to bring it down to around 5.4 (according to my meter that would take roughly 2.5ml of phos in previous batches). But this time I let it ride. By the time it hit the boil kettle ph was in the mid 5.7's, and again I let it ride. I noticed a really good break in the kettle, and a nice clear wort, something lacking in recent batches. Cooled to 47 pitched proper yeast, oxygenated, and set in the fridge at 51.


Now on to my theory.. I really really think my meter is off when it touches wort, the samples I pull go into little vials and get cooled by running water, they are completely free of any particles, at room temp, and the temperature probe goes in with the probe. In talking with others I am thinking brunwater is more accurate, and I end up dropping the ph really low, thus causing the flavor.

What say you experts?

There are certainly ways that a pH meter can lead you astray and drift is one of them. If your meter comes up with calibration constants based on readings before the electrode is fully stabilized, and many meters make the decision as to when the reading is stab le though you may be have some control over its decision threshold, then all readings taken subsequently will be off. A simple check on whether this is happening or not is described in Step 11b of the ph Meter calibration instructions in the Sticky on that subject. If you can't control when the meter takes its cal readings you can override the meter's calibration and use your own. If that turns out to be the case for you post again and I'll list instructions for doing that. Specify whether your meter has a mV mode or only reads pH.

5.67 is a reasonable pH for your mash without the acid malt. pH 5.37 - 5.47 is what you'd expect with the acid malt.Thus having the pH as high as 5.67 and having ir rise during the mash, lauter/sparge etc by 0.1 does cast suspicion on the meter. Do the stability check.