High pH (6.10) after boil

[hilljack13]

Today I did a 1 gal batch and after the boil, the pH was 6.10. I thought that was extremely high. Pre-boil was 5.45 so I figured it might go up a bit. I ended up getting it back down to 5.43 after acid addition. I put ~10-12ml in. I thought that was high. The acid was 10% PA. Does any of this seem off and did I mess anything up?

EDIT: I am doing an Ofest test. 90% pils, 10% munich
EDIT 2: I always cool a testing sample ~65F

 

[marc1]

How are you measuring pH?

 

[hilljack13]

Aptera 60. I can't remember full model, but I did a 3 point calibration before I even crushed grains this morning.

 

[marc1]

That's very strange. I wouldn't expect the pH to change that much during the boil.

IIRC it should also generally go down slightly during the boil, not up.

Are you adding anything besides hops to the boil?

 

[hilljack13]

Just the normal salts. I'm using RO water. Only thing I did different was to use a hop bag just to keep trub lower when transferring.

I also used yeast nutrient for the first time, but I wouldn't think that has anything to do with this.

 

[marc1]

What salts did you add?
Was Fermax the nutrient?
There was another thread where this seemed to be the pH-altering variable, but it doesn't seem like it should be. Maybe there's a bad batch of Fermax out there?

https://www.homebrewtalk.com/threads/very-high-post-boil-ph.730650/page-2#post-10402669

 

[MaxStout]

A quick search shows DAP having a pH in solution of around 7.5-8. It (or something similar) could be the culprit.

 

[hilljack13]

Normal, gypsum, calcium chloride, and Epson based on brewfather recommendations. Nothing out of the ordinary.
I have the LD Carlson yeast nutrients. This one.
Looks like it does have DAP in it. I would have to double check with the bag. Is this one not commonly used?
Guess it is a good thing it only goes in the boil and just before finish.

 

[marc1]

You could check if that's it. Make a small batch of wort, check pH, add minerals as normal, check pH, split it in 2, add DAP to 1, chech pH again, boil, check pH of both at completion.
That'll give you an idea what the DAP is doing. You can then use the wort for starters if you want, so it's not wasted.

 

[refect]

What style beer did you make? What all did you add during the boil? A ton of hops and/or some adjuncts can cause pH to rise. Is it possible the pre-boil wort was not homogenized and your initial sample was off?