mash ph adjustment technique

[UltraHighABV]

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

 

[JordanKnudson]

Are you sure you were too high? Remember, room temperature pH reads about 0.3 higher than at mash temp. Did you account for that?

EDIT: to add to that, I think the only reason to measure your pH at room temp is if your equipment requires it. What you are interested in is the mash temp pH anyway

 

[benner7746]

The best way, I have found, to adjust your PH in mash is to pre-plan all water adjustments prior to ever starting. I use an online calculator that factors my water profile, grain choices, and any mineral additions. It seems daunting at first, but it avoids having to do major course corrections on the fly. I have soft water, so I use a small bit of acid malt in almost every beer I make to get a solid 5.2-5.3 PH.

 

[mabrungard]

Trying to chase a mash pH value without knowing what the approximate initial adjustments should be is just like a dog chasing its tail. After a couple of rounds, you won't know where you are. It is FAR better to know your water chemistry and plan the necessary adjustments. Most of us go ahead and implement those adjustments and then check mash pH, but some like to wait and see. If you've already calculated the adjustments, then you can get ahead of the game without trial and error.

 

[UltraHighABV]

Are you sure you were too high? Remember, room temperature pH reads about 0.3 higher than at mash temp. Did you account for that?

EDIT: to add to that, I think the only reason to measure your pH at room temp is if your equipment requires it. What you are interested in is the mash temp pH anyway

arent we interested in a room temp ph of 5.2-5.6, not mash temp ph?

i havent measured ph at mash temp, not bc of fear of damaging the instrument, but moreso for accuracy. how close is the .3 to rt ph at the 147-153 temp range?

so mash temp ph should be targeted at 4.9-5.3?

 

[Yooper]

arent we interested in a room temp ph of 5.2-5.6, not mash temp ph?

i havent measured ph at mash temp, not bc of fear of damaging the instrument, but moreso for accuracy. how close is the .3 to rt ph at the 147-153 temp range?

so mash temp ph should be targeted at 4.9-5.3?

Yes, room temperature mash pH is the standard. You want 5.3-5.5 or so, but I go more or less, based on styles (5.2 for dry stout, 5.35-5.4 for IPAs, 5.5ish for oatmeal stout, etc).

I don't know what mash temp pH should be- it's rarely used.

 

[Yooper]

Anyway, I cool the small sample to room temperature quickly by putting my sample in a shot glass, and suspending that in a little cup of ice water and stir. It cools in just a few minutes, far faster than putting it in the freezer does.

 

[UltraHighABV]

thanks yooper thats a good idea

 

[jimyson]

Yes, room temperature mash pH is the standard. You want 5.3-5.5 or so, but I go more or less, based on styles (5.2 for dry stout, 5.35-5.4 for IPAs, 5.5ish for oatmeal stout, etc).



I don't know what mash temp pH should be- it's rarely used.

I thought that the pH ranges you detail are preferred at mash temp and when measuring these at room temp, they are about .3 higher in your reading, so you should actually see average at 5.6-5.8 since the pH has increased as the temp drops.

 

[Yooper]

I thought that the pH ranges you detail are preferred at mash temp and when measuring these at room temp, they are about .3 higher in your reading, so you should actually see average at 5.6-5.8 since the pH has increased as the temp drops.

No, 5.3- 5.5 are ideal mash pH taken at room temperature.

 

[Gavin C]

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.

 

[mabrungard]

Interesting Gavin. Your data shows something that I've contended for almost a year. Room-temp mash pH tends to correct itself toward a pH of about 5.4 during the mash. If the pH starts out higher than that, it tends to drop and if it starts at a pH lower than that, it tends to rise. I don't know what causes it, but I've seen a large amount of data and that trend is prominent.

Another reason not to worry too much about pH. If you've calculated and applied reasonable water treatment, it is more likely to end up in a good zone.

 

[Gavin C]

Interesting Gavin. Your data shows something that I've contended for almost a year. Room-temp mash pH tends to correct itself toward a pH of about 5.4 during the mash. If the pH starts out higher than that, it tends to drop and if it starts at a pH lower than that, it tends to rise. I don't know what causes it, but I've seen a large amount of data and that trend is prominent.

Another reason not to worry too much about pH. If you've calculated and applied reasonable water treatment, it is more likely to end up in a good zone.

That's really interesting.

A couple of things I've also been wondering about related to full volume mashes and fine milling include.

• Should I and others like me using full-volume mashes be targeting a slightly higher mash pH than if using a more typical water/grist ratio to offset for the increase in the kettle pH after sparging is completed. (Targeting a similar kettle pH while not actually measuring it).
  
• With a finer crush and a increased mash kinetics, should one be measuring mash pH sooner than 20-30 minutes, especially if it's true that mash pH is tending to a ~5.4 range over time

These are just things to consider for folks using a similar approach. I certainly don't claim to know the answer to either.