Kettle PH

[SpeedYellow]

So just to clarify for myself.. The goal when you start to try controlling your PH levels is to match your sparge water's PH to your Mash PH or else it's really all for not, right?

Nah, matching sparge water pH to mash pH doesn't need to be a goal. For example, some folks will sparge with distilled water, and they might just skip acidifying it. And let's say your first runoff is 5.2 but your second runoff is 5.4 because you barely (or didn't) acidified the sparge water. Is that a problem? Of course not; it just means your kettle pH will be say 5.3.

There are rules-of-thumb for acidifying sparge water, like Miller says to acidify it to 5.7. I've seen other numbers too.

 

[Roadliner]

ok. So to my understanding (and I'm just starting on all of the sciences behind cooking and brewing more than 8read recipe.. follow recipe) The mash would have a certain PH to maximize it's efficiency in converting you sugars, but a lower efficiency is better for your finished wort to promote yeast activity, correct?

 

[ajdelange]

The goal in adjusting sparge water pH is to help set the kettle pH where you want it. This is usually a bit below finished mash pH and so one may want to acidify the sparge water somewhat. Or you can refrain from acidifying the sparge water and add the acid to the kettle. Doesn't matter as long as the acid goes in there. In many cases, acid is not needed (I have never used it). There is only one case where sparge water must be acidified and that is where it is alkaline enough that it can pull mash pH up or that it pulls up runoff pH to over 6 before you have collected as much wort as you want (runoff gravity is too high).

 

[BeerGrylls]

Keep in mind that as the kettle run off becomes low gravity, in the 1.011-1.009 range, it has very little buffering power and thus the pH is likely to easily rise to the 6.0 range. This promotes tannin extraction and astringency well within taste thresholds in the final product. That's why it's important to keep your sparge water acidic and cease lautering when the gravity gets to around 009. The fantastic book 'water' is extensive in the subject, both scientifically and empirically.

 

[Roadliner]

I've got that on my reading list for when I get home. Along with the other books in the series.

 

[mabrungard]

Keep in mind that as the kettle run off becomes low gravity, in the 1.011-1.009 range, it has very little buffering power and thus the pH is likely to easily rise to the 6.0 range.

That is my experience. There is very little chance of tannin or silicate extraction into the wort, regardless of temperature and somewhat regardless of pH, when the wort gravity is relatively high. It is not until the gravity falls into the 3 or 4 brix range that there is much opportunity for damage. Then having the sparging water alkalinity and temperature in the proper range is very important.

Those of you batch sparging, have less to worry about since the final runnings tend to be much higher gravity than the danger point I mention above. You lose some efficiency, but should be less apt to extract the bad stuff. Of course, you still need to acidify the sparging water to bring its alkalinity down.

I still fly sparge and have to be careful with stopping the runoff at low gravity or my beer does display slight astringency. Lately, I've been reserving the last 1 to 1.5 gal of the calculated sparging volume from the mash and just adding that as pre-boil top-off water in the kettle. That is working very well.

 

[ajdelange]

If wort is at pH high enough to ionize phenols there is no mechanism I can think of whereby high wort gravity provides any protection against dissolution of the phenols. It shouldn't be a question of ionic strength as the ionic strength of wort is modest at worst i.e. not high enough to cause significant deviation from ideal behavior (I don't think) and certainly not high enough for 'salting out' to be taking place. What do you have in mind here?

 

[BeerGrylls]

It's all in the phosphate buffering power at high gravity concentrations that keep the pH low.

 

[ajdelange]

Low buffering simply means that it takes little acid or base to move pH. I'm not questioning that. My question was with respect to the statement that tannin extraction is more or less independent of pH if the wort is strong. The statement was made that there is little opportunity for damage until the wort reaches 3 - 4 Bx but does not state that this is because one can quickly slip to pH of > 6 rather implying, as I read it anyway, that it isn't the pH but the Bx that causes tanins to move.

 

[BeerGrylls]

I went back and read Martin's comment once more and now I see what you're questioning. The data I know of tells us that the pH is the principal driver behind tannin, ash, and silicate extraction. But if there's data to show that gravity is directly responsible for astringency compounds then maybe it's important we know about it. AJ, I know that you worked closely with Colin to flesh out chapter 6 of his Water book (which I will continue to shout is a phenomenal resource) so I don't expect I'll be correcting you! I think I just read Martin's comment to mean that he was shortcutting the progression of low runoff brix -> increased pH.

 

[mabrungard]

Yes, there is published evidence in Malting and Brewing Science in the form of a graph. Unfortunately, my volumes of that text are at home and I can't cite the figure number. Wort gravity has a major influence in tannin and silicate extraction.

When I mentioned 'somewhat regardless' for the pH, that was assuming that the wort pH was not wildly out of range (<6). If it is higher than that, there will be other problems that will affect the beer.

 

[ajdelange]

Mine are also 600 miles away so I can't check. In interim you will have to color me very skeptical as I can't think of any physical phenomenon that would induce 'major' influence. I have listed the things it shouldn't be in a previous post. Perhaps there is some phenomenon that I haven't heard of that would explain it.

 

[ParanoidAndroid]

I brewed yesterday and decided to keep up with everything. Brewday was kind of a mess, so I am trying to record all kinds of info and get in a rhythm. The recipe was a modified lil sparky nut brown:

2.25 Gallon Batch (BIAB)
100% Distilled Water
Starting volume = 3.60 gal

3.304 lbs Marris Otter
0.367 lbs Flaked Oats
0.184 lbs Victory
0.367 lbs Crystal 60
0.092 lbs Chocolate

0.39 oz Fuggles @ 4.7% & 60 Min
0.33 oz East Kent @ 6.3% & 15 Min

S-05 Yeast

1.1 grams Gypsum
1.1 grams Calc Cl
1.0 mL Lactic Acid

I have a MW-102 pH Meter. I calibrated it 3 times throughout the process. I used Brunwater and input my Marris Otter, Oats, and Victory, along with my salts and acid and had a predicted mash pH of 5.45.

1. Initial Distilled Water pH = 4.39
2. Initial Distilled Water with salts and acid = 3.59

Mash pH

3. 15 min = 5.29 @ 88 deg F (No Crystal or Choc)
4. 30 min = 5.33 @ 89 deg F (No Crystal or Choc)
5. 45 min = 5.33 @ 88 deg F (No Crystal or Choc)
6. 60 min = 5.37 @ 82 deg F (No Crystal or Choc)

Mashout pH (added chocolate and c60 at start of ramping to 168-170 deg. this took 35 minutes. due to this taking so long, I only did a 5 min mashout. 0 min is the start of 168 deg F)

7. 0 min = 5.25 @ 82 deg F (all Malts)
8. 5 min = 5.21 @ 84 deg F (all Malts)
9. After Squeeze of bag = 5.15 @ 80 deg F (all Malts)

Kettle pH

10. 15 min = 5.16 @ 80 deg F
11. 30 min = 5.10 @ 67 deg F
12. 45 min = 5.05 @ 80 deg F
13. 60 min = 5.08 @ 80 deg F

14. Post Chill pH = 5.10 @ 67 deg F

So there's 14 pH readings. Its definitely overkill, but I was interested in how it reacts throughout the process. I assume around 80-90 deg is okay to take a pH reading? If not, is there a conversion to room temp Ph?

After a few readings I put the probe back in the buffer solutions. It was always within +/- 0.03 of the buffer....except for the #1 and #2. They were -0.05 off.

Ive attached my spreadsheet that has everything.

View attachment Nut Brown 2xml.xml

 

[ajdelange]

So there's 14 pH readings. Its definitely overkill, but I was interested in how it reacts throughout the process.

And now you have a pretty good idea of how it changes during the process so it wasn't overkill at all. Do this a few more times to get a feel for what kind of variation you can expect from batch to batch and for different styles of beer. From there on a check at a couple of points should suffice.

I assume around 80-90 deg is okay to take a pH reading?

It is and it isn't. If you do take measurements at an elevated temperature you will shorten the life of your electrode because of the thermal stresses temperature change puts on it. Also, if you measure at temperature other than the calibration temperature you rely on your meter's ATC algorithm which is only dead nuts on if the electrode's isoelectric pH is 7 and no meter I know of allows you to adjust if it isn't (which is why I do ATC in my computer). If you plan to measure at elevated temperature you should calibrate at elevated temperature too.

If not, is there a conversion to room temp Ph?

It depends on the temperature offset. I have used 0.0055 pH/°C only to find that it is malt dependent. This is why most people simply use room temperature pH readings.