I ran into this problem last week:
I start my mash, wait 10 min, then pull a sample to check the pH, however its 150deg so i put it into the freezer to get it to room temp asap; 15 minits later i see that im too high and add some acid; i pull another sample after mixing but again this takes 15-20 to get to rt for measuring, and by this time my mash is almost done
how do you guys do it so you can make adjustments quickly and accuratley?
thanks
You shouldn't attempt to make intra-mash pH adjustments for a number of reasons.
Reasons not to make intra-mash pH adjustments
- Mash pH is not a constant
- Mash ph requires some finite time to stabilize
- Once a stable mash pH is known it's too late to effect any control over the chemical reactions dictating the pH. The reactions have already happened
- Any pH mediated enzymatic control of these same reactions is now not possible. The reactions have already occurred.
Intra-mash pH adjustments are thus ineffective, inaccurate and unpredictable.
Lets suppose you are performing a mash.
A number of chemical reactions are taking place in the mash. It's these you want to control.
These reactions as they occur give rise to a non-constant mash pH
You take a sample, cool it measure its pH and decide to add some acid/alkali/thin the mash to cause a change.
Ask yourself a few questions.
How much should you add. How much of a change do you want?
Has the mash pH stabilized?
Is the sample pH representative of the mash now that some more time has passed since the sample was taken?
How much more mash chemistry is left to happen after all this time?
Here is a better way using a recent brew as an example
Calculate a predicted mash pH and make changes targeting a pH of your choosing.
Planned Mash
On my setup I typically find Bru'n Water to constantly predict a little higher than measured mash pH so offset this by aiming a touch higher than planned. In this instance targeting 5.45 so input mash details to give a figure of 5.50. While this is less than ideal perhaps, I find it to be predictable.
To lower the ph add acid in one of its forms
- Acidulated malt
- Lactic Acid
- Dark malts
To raise the ph (rarely be needed)
- Add alkali (never use chalk)
- Mash thinner
Carry out the mash and take a sample. When to take the sample is open to debate but 20-30 minutes in, would probably be reasonable to most.
Measure the pH (multiple measures made here to illustrate the changing pH over time)
- Record any difference between planned and measured pH
- Tweak the amount of acid (usually acid) to add to similar future mashes based on this data.
- Over successive brews as your data pool grows your planned and measured mash pH are likely to grow ever closer.
Hope that is of some use. Best of luck with your brewing.