My first attempt at pH control - low pH throughout?

[MNDan]

Just got a PH56 pH meter and brewed my first batch with it last weekend. Calibrated it by following the nice video on how to calibrate it on their website. Pretty straight forward, though after calibration it read about .08 lower than expected in the 7.01 buffer - oh well, within the variance I guess. Didn't really like the fact they they make you go quickly from the 7.01 buffer to the 4.01 buffer without rinsing the probe, but I guess they know what they are doing.

Brewed a simple pale ale with 22 lbs of grain, of which 1 lb was crystal 40 and 1 lb was light munich malt. Used 100% RO water to make it easy. Plugged in the numbers to the EZWaterCalculator spreadsheet, and then figured my mash additions to be 5 grams of CaSO4 and 5 grams of CaCl2 along with 6 ml of lactic acid for an estimated 5.26 mash pH @ 152F. Also added 5.6 grams of the salts into my boil to adj for sparge water. 8 gallons mash/9 gallons sparge of RO water.

When I cooled the mash liquor after mashing for around 20 minutes it measured at 5.23 pH @ 80F. Way too low, right? Final cooled wort pH post-boil was 5.19@80F. I know that the spreadsheets are only a simple way of estimating a complex process, so perhaps for lighter beers they don't work as well?

And more importantly, will my beer be OK? I'm not worried, but just curious.

 

[ajdelange]

Pretty straight forward, though after calibration it read about .08 lower than expected in the 7.01 buffer - oh well, within the variance I guess.

I don't think it is. What do they specify for accuracy?

After calibration the meter should read the pH of the buffer pretty darn close. If it doesn't the cal is invalid. This can happen if you accept a cal reading before the electrode has come to equilibrium.

Didn't really like the fact they they make you go quickly from the 7.01 buffer to the 4.01 buffer without rinsing the probe, but I guess they know what they are doing.

I don't like it either. You should remove the electrode from the first buffer, rinse it with DI water, pat it dry with a paper towel (it doesn't have to be really dry - just get as much water as possible off the bulb guard, without touching the bulb itself, in order to prevent dilution of the second buffer) and then immerse in the 2nd buffer.

Brewed a simple pale ale ... 5.26 mash pH @ 152F. ...When I cooled the mash liquor after mashing for around 20 minutes it measured at 5.23 pH @ 80F. Way too low, right? Final cooled wort pH post-boil was 5.19@80F.

I know that the spreadsheets are only a simple way of estimating a complex process, so perhaps for lighter beers they don't work as well? [/quote]

Estimating 5.26 and coming up with 5.23 says the spreadsheet made a pretty good estimate. I wasn't aware that the EZ spreadsheet took temperature into consideration. Perhaps this is the adjustment in mash shift with temperature?

Anyway, if you have a pH meter you should be ruled by that and informed by the spreadsheet. Go easy on the salt additions and rely on the acid to get your mash pH, as determined from pH meter readings, correct. But be sure you get the questions about calibration of the meter resolved.

And more importantly, will my beer be OK? I'm not worried, but just curious.

I'm sure it will. In the future you may wish to use less acid (or sauermalz) to hit a pH of 5.4 or so rather than 5.2 but 5.2 should not screw the pooch.

 

[MNDan]

Probably wasn't clear - the spreadsheet said I should end up at 5.26 at mash temp (152F). I measured 5.23 at room temp, which, with the .35 shift, would be a mash pH of 4.88@152F. Not good.

 

[ajdelange]

Your pH shift will probably be more like 0.22 - 0.27 for an actual pH at 152 of 4.96 - 5.00. And your description of the calibration process makes the reading of 5.23 suspect. You will probably be OK in any case. There are those who think 5.2 at room temperature is fine though most would probably push you towards something like 5.4.

In the future calibrate the meter as I described in the previous post (be sure to use fresh buffer) and check against a DI solution of 5.2 (should read 5.82 if you like). Then add half the acid (or sauermalz) check pH (you need to give the acid some time to work) and only add the second half if you need it.

 

[remilard]

Probably wasn't clear - the spreadsheet said I should end up at 5.26 at mash temp (152F). I measured 5.23 at room temp, which, with the .35 shift, would be a mash pH of 4.88@152F. Not good.

I just downloaded the current version of the EZ Water spreadsheet and it neither claims to be estimating the mash temperature pH nor is it attempting to if you audit the calculations. What makes you think it should have been 5.23 at mash temperatures? Do you have an older version?

 

[MNDan]

I have the 2.0 version (newest I believe). The spreadsheet specifies "mash pH" only. Without a temperature indication, I have to assume they mean the actual pH of the mash at it's mash temperature. Keiser's spreadsheet estimates my mash pH at room temp to be 5.38, which is close to the .2-.3 range of temperature shift I'd expect.

I wish I could calibrate it the way you specify, AJ, but sadly my pH meter doesn't let me as near as I can tell. I only have a couple of seconds to switch it over.

http://www.milwaukeetesters.com/video-cal-pH55.html

 

[wildwest450]

I have the 2.0 version (newest I believe). The spreadsheet specifies "mash pH" only. Without a temperature indication, I have to assume they mean the actual pH of the mash at it's mash temperature.

That would be an incorrect assumption. It's at "room" temp. I always check mash ph at the temp I calibrate my ph meter at, which is "room" temp or 68f.

 

[MNDan]

That would be an incorrect assumption. It's at "room" temp. I always check mash ph at the temp I calibrate my ph meter at, which is "room" temp or 68f.

Interesting. I think you should probably indicate that on the spreadsheet like Braukaiser does on his, since it's very important. Also, I've never read that a desired mash pH at room temperature is 5.2-5.4 (as indicated on your spreadsheet). Usually it's 5.5-5.8 at room temp, right?

The good part is that the spreadsheet looks to have estimated the pH correctly. Pretty much spot on in my case. Braukaiser's spreadsheet gives me a mash pH of 5.37 @ 68F. Wonder why there is this much difference?

 

[wildwest450]

Interesting. I think you should probably indicate that on the spreadsheet like Braukaiser does on his, since it's very important. Also, I've never read that a desired mash pH at room temperature is 5.2-5.4 (as indicated on your spreadsheet). Usually it's 5.5-5.8 at room temp, right?

The good part is that the spreadsheet looks to have estimated the pH correctly. Pretty much spot on in my case. Braukaiser's spreadsheet gives me a mash pH of 5.37 @ 68F. Wonder why there is this much difference?

Not my spreadsheet, the guy who made it is TH, he's aroud here somewhere.

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