PH questions

[john luc]

I use beersmith3 and in it you can set up water profiles to add salts to either the mash or split them between mash and sparge or mash and boil. I have done all of these. I also take plenty of notes on brewday and what I notice is that my PH numbers don't go as planned. I use RO water and although it's hard to get a steady measure it seems to settle around 5.4 / 5.5 PH. SO WHEN used to sparge a mash with has 5.3PH the last runnings are coming out 5.9 PH.

[john luc]

My wort comes in at 5.5PH. my final sparge runnings are 1009 gravity. when I compete the boil I find the PH to be 5.9. Only thing I attribute to this may be the late hop which I add at 70C for 2o minutes.

[Eric]

What was the pH of your last runnings at 1009? Boiling usually reduces pH by ~0.2. with sufficient calcium in the boil.
If sparge liquor and mash liquor are similar, the pH of runnings will rise in line with the wort gravity reduces, such that first wort might be pH 5.5 while later running can be pH 6 and higher with adequate calcium present.

[Silver_Is_Money]

I agree with Eric. Most data indicates that pH falls across the boil. And some data indicates that the higher the pH is leading into the boil, the greater the measure of the drop will be. This data also shows that if the Wort is acidified to 5.1-5.2 pH just prior to the boil step there will be little to no further drop across the boil. Here is some data claimed to be sourced from the highly regarded Narziss:

1) A Wort which started the boil at a room temp. pH of 5.78 exited at pH 5.48. Drop = 0.30 pts.
2) A Wort which started the boil at a room temp. pH of 5.64 exited at pH 5.41. Drop = 0.23 pts.
3) A Wort which started the boil at a room temp. pH of 5.48 exited at pH 5.30. Drop = 0.18 pts.
4) A Wort which started the boil at a room temp. pH of 5.32 exited at pH 5.19. Drop = 0.13 pts.

This data can be found here: https://onlinelibrary.wiley.com/doi/epd ... .tb03663.x

This equation which I devised attempts to mirror the Narziss data. At a boil entry pH of approximately 5.0 the boil induced pH drop does not occur, as at boil exit the pH will still be 5.0. Here is the equation: pH_Knockout = 1.86336 + (0.62686 * pH_Pre-Boil)

A boil entry pH of 5.1-5.2 is generally desired, and many sources advise to acidify to 5.1-5.2 pH pre-boil whereby to achieve the best possible hot and cold breaks, while requiring the least amount of fining's such as Irish Moss or Whirlfloc.

[john luc]

My last runnings this time were PH 5.8 and the gravity was 1009. The PH of my wort going to boil was 5.5 and I added first wort hops and steep hop at 70C for 20 minutes. Thing is, my wort after boil was 5.9PH which means it rose instead of falling.

[Silver_Is_Money]

I can't fathom the mechanism that would cause pH to rise across the boil. As Eric said, calcium should promote a drop.