Martin B. is the man!

Brewing Processes
21

Huh? Mash Ph at mash temp ( temp corrected to room temp) should be same as room temp PH.

22

I’ve heard this both ways too.  My last batch I took a reading of my sample while it was hot and then after it cooled.  I got the same reading.  Going to try this experiment again next batch, mainly because I want it to work!

23

Without temp correction ph will be different hot vs room temp. It will also shorten life of probe.

24

Yeah mine has temp correction.  I’ve just heard varying opinions on whether it actually works.

25

The temp correction is for the electronics, not the reaction vs temp.

26

No, the pH of a solution goes down as temperature rises.  Neutral pH at room temperature is 7.0.  Neutral pH at 100C/212F is 6.14.

T (°C) 	Kw (mol2 dm-6) 	pH
0 	0.114 x 10-14 	7.47
10 	0.293 x 10-14 	7.27
20 	0.681 x 10-14 	7.08
25 	1.008 x 10-14 	7.00
30 	1.471 x 10-14 	6.92
40 	2.916 x 10-14 	6.77
50 	5.476 x 10-14 	6.63
100 	51.3 x 10-14 	6.14
27

so if that were the case, anyone taking mash PH that cools to room temp doesnt have an actual PH to compare to their target PH. unless Im missing something, that would be significant if your cooled mash temp was 5.2-5.5… that would mean the actual mash PH would be lower by about .4-.5 (150F mash vs room temp sample of 70F)???

so every PH reading I take that is cooled, I should correct lower by a factor of .4-.5?  if this is accurate, that’s news to me!

here’s similar discussion with Kai’s comments on this: https://www.homebrewersassociation.org/forum/index.php?topic=702.0

"In short:

  • don’t test at mash temp since this shortens the life of your pH meter probe
  • the room temp to mash temp pH shift is more like 0.2 than 0.35
  • Mash pH optima are generally reported as room temp pH values and by comparing them to room temp measurements you remove the ambiguity.
  • A correct room temp mash target range is 5.3 – 5.6 with the boundaries being quite fuzzy. I.e  5.2 and 5.7 should work too.
  • Don’t worry what the actual mash temp pH values are.

Kai"

28

According to Kai somewhere, the brewing literature (was it Narziss?) states that you want a reading of 5.3 - 5.6 at room temperature. After reading that I stopped worrying about the shift to a lower value at higher temperatures.

29

read what kai wrote again. He says optima are stated at room temp. so by cooling your sample to room temp you are ‘removing the ambiguity’. so 5.2-5.7 is optimal AT ROOM TEMP. you are doing the readings just fine.

30

that’s what I took away also- thanks.

31

FWIW I thought Brunwater was also slated for room temp readings. I.e. 5.3 in brun water assumes you are measuring at room temp.

Which is why I asked S. why he target a higher end of the spectrum mash ph.

32

You are correct. While anywhere in the spectrum is acceptable to minimize the risk of tannin extraction and allow the enzymatic processed to work well there are perceptable differences in flavor and, according S. hop utilization. between 5.3 and 5.5. it’s pretty subtle stuff but it can make a real difference. higher pH tends to accentuate hop flavor to some extent.

33

Yep, I like 5.4 for hoppy beers.

34

However, what matters to enzymatic hydrolysis is the pH at mash temperature, not the pH at room temperature.  A pH of 5.6 at room temperature is as pH of around 5.3 at mash temperature. I thought that this information was common knowledge.

35

The problem Mark is that while you are correct on difference in PH at mash temps vs room temp-all the information home brewers have as reference to mah PH and its impact on the beer is relative to mash PH at room temps. Kai’s article is just one example, and this forum has more references than you can count.

That’s why alarms went off in my head when I read your post-thought I was doing something wrong. I just never read or heard of anyone taking PH of mash at room temp and adjusting it for mash temp PH.

36

It is common knowledge, but I don’t think the actual shift is .3, closer to .2…  I am also fully aware of targeting higher ph’s fro the beers. I.e. For a pils I target 5.2-3 for a nice crisp finish (also helps the yeast work faster). I also target 5.4-5 for hoppy American beers, just never went as high as 5.6. I think Kai did a test on higher wort pH’s, but didn’t know if I missed something.

37

i have an old probe on one  of my meters i’m replacing when new one comes in. think just for the heck of it i will take a reading at mash temp and compare it to room temp this weekend…see what the shift really is.

38

All of my references point to optimum mash pH being between 5.2 and 5.3 at mash temperature.

39

feel like a storms coming on this one…

40

Well this post was all about Brunwater… Brunwater is made to read with a room temp sample. That sample is correlated to mash temp. If Brunwater says 5.3 mash pH, its expects you to read 5.3 on your cooled sample because it does/did the guess work(pH temp shifts) for you.  I think you are thinking if Brunwater reads 5.3 at mash you need to read 5.6 at room, right?

I don’t think anyone is disagreeing with you on pH values.

Also in looking at your sample picture, you have WAY to much grain in that sample. You should really have a nice clear (free of particles) sample.