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ddc69
Joined: 13 Jan 2012 Posts: 118 Location: Parkersburg, WV
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Link Posted: Thu Apr 04, 2013 6:49 pm Post subject: Mash pH (What Confusion!?!) |
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My head is about to explode! There is such confusion not only about the optimum pH range but more importantly at what temperature these optimum's are measured at.
I have now learned, I believe, that the pH is affected two ways by temperature which is why measuring the mash pH at room temperature is important. "The first is a chemical change caused by the change in the energy in the water that makes it easier to split hydrogen protons from acidic molecules in the mash. The second component is due to the change in electrical response of the pH meter probe electrodes with temperature. These two factors produce a mash pH that measures about 0.2 to 0.3 units lower at 150°F than at room temperature." (Bru'n Water-water knowledge page)
I'm not really sure it matters where you take the reading, as long as the shift between mash temperatures and room temperature readings are consistent. However, I don't really know if this is true. I will be doing some tests and post the results. I have also read that taking readings at room temperature are easier on your pH probe and will make them last longer.....again I have no evidence of this to date.
I think the most confusing thing is the optimum range. More specifically, at what temperature are these optimums we read about in literature. Unfortunately, it looks like there are several sources that mix and match optimum ranges at either mash or room temperature which has caused a lot of confusion. I think, I felt a little better after reading the following sources:
http://braukaiser.com/blog/blog/2011/03/02/about-ph-targets-and-temperature/
https://sites.google.com/site/brunwater/water-knowledge
So, I think where I am at now is to do some testing to validate the room temperature vs. mash temperature shift and get an idea of how consistent it is. Once I have this data I will decide on what temperature to actually take my pH readings going forward....leaning towards room temperature at this point.
As for some of the threads I have seen on this forum about mash efficiency, I wondered across this little tidbit in my journey for pH wisdom. Puts the complexity of it all in perspective:
http://braukaiser.com/wiki/index.php/Effects_of_mash_parameters_on_fermentability_and_efficiency_in_single_infusion_mashing#mash_results
OK Guys, let's hear your thoughts!
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huaco
Joined: 05 Apr 2012 Posts: 1506 Location: Burleson Texas
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Link Posted: Thu Apr 04, 2013 7:06 pm Post subject: |
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I just got a pH meter. I will be trying to wrap my head around all this soon!
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Ben58
Joined: 14 Aug 2011 Posts: 409 Location: Hamilton, Ontario
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Link Posted: Thu Apr 04, 2013 9:10 pm Post subject: |
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I've got a Hannah pHep 5 and it temperature compensates, so I just check in the mash pot, read and rinse.
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perogi
Joined: 12 Feb 2012 Posts: 850 Location: NH
Drinking: Perogi Pale, NEIPA, Nutter's Crossing Nut Brown Ale, Edmund Fitzgerald Porter Clone
Working on: Max's Maibock
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Link Posted: Thu Apr 04, 2013 10:42 pm Post subject: |
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Ben58 wrote: | I've got a Hannah pHep 5 and it temperature compensates, so I just check in the mash pot, read and rinse. |
+1 ditto!
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ddc69
Joined: 13 Jan 2012 Posts: 118 Location: Parkersburg, WV
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Link Posted: Fri Apr 05, 2013 12:47 am Post subject: so do I |
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So do I. However, in my reading, temperature compensation is not enough. The mash pH also changes with temperature due to the chemistry. Take a look at the links in my original post. I thought that a temperature compensated probe was enough until I started digging into the issue.
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11123 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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Link Posted: Fri Apr 05, 2013 2:00 am Post subject: |
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Definitely a confusing subject.
I've actually been reading a lot about this over the last week as I've been working on my water adjustment article and the information is all over the place, including supposedly "real" information from legit brewing books like Gordon Strong's book that basically says that if you use a pH meter with automatic temp compensation (ATC) you're good to go. That conflicts with the links above.
Much documentation don't mention temperature at all (no standard). Some say, use a pH meter with ATC and you're ok. So I'm not sure what the answer is.
My gut feeling (I haven't tested yet) is that the difference measuring with a pH meter with ATC at mash at room temp and 140-150F is probably pretty small. Much smaller than the 0.2 - 0.3 difference you get just from the temp.
(This 0.2-0.3 difference is why EZWaterCalc says to target 5.4-5.6 room temp but all other documentation tends to say that mash pH should be 5.2. The 5.2 is at mash temp).
I'm getting great beers and excellent conversion so I don't doubt it's working well (and don't necessarily plan on changing anything) but I would be good to get this right.
One thing I've found intersting with mash pH is that generally speaking it just always ends up reasonably right and conversion happens. I'm more overly concerned with getting the salts right for flavour and less so about mash pH. Sort of makes sense since historically, people have make been forever and never new about mash until recently. It's only the very lightest beers that tend to read at a slightly high pH so I add some lactic. Everything else gets down to the right range without any help other than the salts I'm already adding.
Another point to consider - if you really want to make your head explode: At what temp should you calibrate the pH meter? We use 4 and 7 pH samples to calibrate, but I've never noticed or read anywhere what these samples themselves are calibrated at or created. Room temp? Or does it even matter?
I hate chemistry!
Kal
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perogi
Joined: 12 Feb 2012 Posts: 850 Location: NH
Drinking: Perogi Pale, NEIPA, Nutter's Crossing Nut Brown Ale, Edmund Fitzgerald Porter Clone
Working on: Max's Maibock
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Link Posted: Fri Apr 05, 2013 11:19 am Post subject: |
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kal wrote: |
One thing I've found interesting with mash pH is that generally speaking it just always ends up reasonably right and conversion happens. I'm more overly concerned with getting the salts right for flavour and less so about mash pH. Sort of makes sense since historically, people have make beer forever and never knew about mash [pH] until recently
Kal |
^ this
There are so many other things to make sure that you "lock down". However, if you are on your 4th Ninkasi Award and want to make sure when the aliens land, you will not only have the best beer in America but also the Universe, then by all means figure it out and write a book so the rest of us can enjoy the fruits of your labor
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ddc69
Joined: 13 Jan 2012 Posts: 118 Location: Parkersburg, WV
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Link Posted: Mon Apr 08, 2013 3:03 pm Post subject: |
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So I did my pH tests this weekend while brewing. What I found is that with the Hanna temperature compensated probe that the diffference between mash temp and room temp was about 0.2 pH units on average. If measuring at mash temp I will just target a pH of 0.2 less than the room temperature recommended ranges.
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11123 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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Link Posted: Mon Apr 08, 2013 3:10 pm Post subject: |
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Thanks for doing this! Can you provide the details on what the numbers were and what the temp was for each?
Kal
_________________ Our new shop with over 150 new products: shop.TheElectricBrewery.com
We ship worldwide and support our products and customers for life.
Purchasing through our affiliate links helps support our site at no extra cost to you. We thank you!
My basement/bar/brewery build 2.0
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ddc69
Joined: 13 Jan 2012 Posts: 118 Location: Parkersburg, WV
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Link Posted: Mon Apr 08, 2013 3:32 pm Post subject: pH test results |
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Temp1 pH1 Temp2 pH2
153F 5.29 75F 5.46 (Test #1)
152F 5.27 74F 5.47 (Test#2)
152F 5.26 73F 5.48 (Test#3)
I will probably repeat this test over the next several batches to soo how consistent it is with different grain bills, etc...
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huaco
Joined: 05 Apr 2012 Posts: 1506 Location: Burleson Texas
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Link Posted: Mon Apr 08, 2013 3:37 pm Post subject: |
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Great data... thanks!
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11123 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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g8tors
Joined: 05 Oct 2011 Posts: 211
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Link Posted: Tue Apr 09, 2013 4:52 pm Post subject: |
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My Hanna pH meter never seems to lock in on a number. It seems to take three to five minutes to get to a number that isn't changing every two seconds. Even then it will slowly fluctuate.
Do you think I need to replace the sensor?
Scott
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ddc69
Joined: 13 Jan 2012 Posts: 118 Location: Parkersburg, WV
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Link Posted: Tue Apr 09, 2013 4:58 pm Post subject: probe drifting |
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I have been having the same problem lately. I will calibrate and eventually settle in on a number but drift for quite some time. I have ordered a new probe. I'm assuming that is the problem. I will let you know if it settles down with the new one. Hopefully have it later this week.
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11123 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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g8tors
Joined: 05 Oct 2011 Posts: 211
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Link Posted: Tue Apr 09, 2013 6:41 pm Post subject: |
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Maybe it could just need batteries?
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ddc69
Joined: 13 Jan 2012 Posts: 118 Location: Parkersburg, WV
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Link Posted: Tue Apr 09, 2013 7:05 pm Post subject: batteries |
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could but my battery indicator on the probe shows that they are fine. I tend to think it is the probe.
I have read some literature, not confirmed by experience yet, that using these probes at elevated temperatures like mash and sparge temperatures reduce the life of the probe.
Depending on where you look the max temperature for this probe is either 140F per Amazon or 122F per Hanna instruments site.
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g8tors
Joined: 05 Oct 2011 Posts: 211
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Link Posted: Tue Apr 09, 2013 9:48 pm Post subject: |
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I ordered a new tip, batteries, and some electrode cleaner. One of those ought to fix it. I know I have checked pH of mashes at temps of 155 so maybe the probe is shot.
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ddc69
Joined: 13 Jan 2012 Posts: 118 Location: Parkersburg, WV
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Link Posted: Sat Apr 13, 2013 7:56 pm Post subject: another data point |
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I did another batch today which was a blonde ale. I took one data point with this batch. This one was a little higher differential at 0.29.
pH at 142F was 5.37
pH at 74F was 5.66
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g8tors
Joined: 05 Oct 2011 Posts: 211
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Link Posted: Sun Apr 14, 2013 11:28 am Post subject: |
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Are those numbers with the new probe?
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