ph of fast ferment sample at 3,85!???

[tomaso]

I brewed my first lager 4 days ago and just checked the fast ferment sample.

It came down from 1,051 to 1,013 which is where it should be but the ph was 3,85! why is it so low???

The mash ph was 5,5 and into the fermentor was 5,36; how did it get down that far?

Thanks!

 

[ajdelange]

You got some wild yeast or bacteria in there. How does it taste/smell?

 

[tomaso]

Haven'T tasted it yet; do I have to suspect that the main batch is infected as well? the starter for the lager yeast I pitched had a sour smell but tasted normal.
I'll take a sample tomorrow from the batch to check ph and taste.

also, another fast ferment sample of a stout that is 12 days old is at 4,14 and isn't nice at all.
Another infection?

And I also just opened a bottled of oktoberfast ale from last July and it tastes sourly off, infected and has a ph of 4,15;

To top that off I just had two local commercial beers, an ESB and a stout, that both weren't bad but I measured their ph while I was at it and it was 3.8-3,9.

Is that a definite flaw? as I read that the ph of the finished beer should usually be in the 4,25-4,6 range...

 

[ajdelange]

pH of finished beers is usually in that range you mentioned so when a beer is outside that range you suspect a problem and often that problem is an infection but not always. If the pH is low and the beer tastes and/or smells foul or is turbid that usually confirms infection. The fact that a forced sample is infected does not necessarily imply that the main batch is also infected but it may. Brewers often will set aside a sample of wort drawn just before pitching and see how long it takes for it to start fermenting. If it is more than a couple of days (it always starts up eventually) the wort is generally considered to have been safe in terms of infection.

And it goes without saying that when one sees a suspicious pH reading or readings the first thing he should do is check the pH meter.

 

[joshesmusica]

AJ, on his two commercial examples, could the carbonation be affecting this low reading?

In other words, OP, did you decarbonate the commercial samples and warm them to room temp before testing.

If you did that, it seems like your pH meter is off. Or else those two commercial samples should be contacted to let them know that something is off with their beers! But considering that you didn't think the two commercial examples were bad, then I'd say you need to check your pH meter.

 

[tomaso]

And it goes without saying that when one sees a suspicious pH reading or readings the first thing he should do is check the pH meter.

I thought the meter worked just fine because a day or two before I put it into the 4,01 solution and it correctly displayed 4,01.

But just now I drew the sample from the main batch (it tastes fine btw) and the reading was 1,89!
So meter is obviously off but I can't seem to calibrate it because in the 7,01 solution it reads about 5,8 and the calibration stops as soon as I start it (Extech 100 is my meter).

Any advice on how to calibrate if my meter is so much off? and why it is that much off???? I stored it in ph meter storage solution and haven't had any problems so far.

 

[tomaso]

So it seems like I managed to calibrate the meter although after some mesasurments it was off by 0,1 again and i calibrated it again but then again it was off by 0,2.
While calibrating it says 'renew' which according to the manual means to change the probe but the meter is only a few months old and was stored in solution all the time!

Anyway, the measurement for the sample first was 4,2 and the second time 4,1 and the last time 4,3; it tastes a bit sourly and off

the measurment for the main batch was first 4,2 and then 4,15 and last 4,5; it doesn't taste good but not sour or really off either.

 

[fun4stuff]

So it seems like I managed to calibrate the meter although after some mesasurments it was off by 0,1 again and i calibrated it again but then again it was off by 0,2.
While calibrating it says 'renew' which according to the manual means to change the probe but the meter is only a few months old and was stored in solution all the time!

Anyway, the measurement for the sample first was 4,2 and the second time 4,1 and the last time 4,3; it tastes a bit sourly and off

the measurment for the main batch was first 4,2 and then 4,15 and last 4,5; it doesn't taste good but not sour or really off either.

Edit: misread

 

[ajdelange]

Any advice on how to calibrate if my meter is so much off? and why it is that much off???? I stored it in ph meter storage solution and haven't had any problems so far.

Yes. Use it as a voltmeter. Read mV and temperature in 4 buffer, 7 buffer and the sample. There are formulas that will give you slope and offset from the buffer readings and another formula gives you pH from slope, offset and sample mV & T. However

1)Having to go to a spreadsheet is a big PITA relative to just reading pH off the screen.
2)While this technique is great for manufacturers that try to push you into buying a new electrode when slope drops below 95% the fact that it has dropped means the electrode is ailing. You probably wouldn't want to depend on an electrode whose slope was 50%.
3)It is especially important that you check electrode stability if you are doing the measurements this way.
4)Most pocket/portable meters don't display mV which moots 1 - 3.

 

[ajdelange]

AJ, on his two commercial examples, could the carbonation be affecting this low reading?

Yes, carbon dioxide forms carbonic acid which lowers pH. John PAlmer wanted to know by how much for some article he was writing and as I recall I calculated 0.1 pH for 2 volumes but that is from memory so accept it at your peril.

 

[tomaso]

Yes. Use it as a voltmeter. Read mV and temperature in 4 buffer, 7 buffer and the sample. There are formulas that will give you slope and offset from the buffer readings and another formula gives you pH from slope, offset and sample mV & T. However

1)Having to go to a spreadsheet is a big PITA relative to just reading pH off the screen.
2)While this technique is great for manufacturers that try to push you into buying a new electrode when slope drops below 95% the fact that it has dropped means the electrode is ailing. You probably wouldn't want to depend on an electrode whose slope was 50%.
3)It is especially important that you check electrode stability if you are doing the measurements this way.
4)Most pocket/portable meters don't display mV which moots 1 - 3.

yes, that indeed seems like a big PITA but thanks anyway for the suggestion.
But why is my electrode already ailing after a few months and with proper storage?? That meter was about a 100E so it's not cheap...
Anything else I can do besides replacing the electrode or getting a new one?

Thanks for your help

 

[ajdelange]

But why is my electrode already ailing after a few months and with proper storage?? That meter was about a 100E so it's not cheap...

Yes, actually it is. A good electrode (without the meter) costs twice that or more but tremendous strides have been made in recent years in inexpensive electrode technology and many manufacturers have released meter in this price range which are pretty good. However, as with any new product, there are often problems when production is just starting up and pH electrodes are basically rather finicky things. Your electrode should not fail after a couple of months and he fact that it did says that it was probably from a 'bad batch'. I would go to the manufacturer or supplier and tell him your story. They may replace the unit for you.

 

[rabeb25]

Come on you guys, its known that the faster and warmer the ferment the lower the final pH will be. This is not out of the ordinary. A healthy fermentation, with an accelerated schedule will always end you up with a lower finished pH.

However the whack readings.. yea something is wrong there.

 

[ajdelange]

Come on you guys, its known that the faster and warmer the ferment the lower the final pH will be. This is not out of the ordinary. A healthy fermentation, with an accelerated schedule will always end you up with a lower finished pH.

But probably not enough to make his meter read 5.8 in 7 buffer.

 

[rabeb25]

But probably not enough to make his meter read 5.8 in 7 buffer.

Yea, like I said, those readings indicate an issue. But the 3.85, no.

 

[tomaso]

My meter has come to life again!
I brewed today and periodically checked the meter in the buffer solutions and it seemed to work just fine!
Could it just have had a bad day?

and about the 3,85; I just had a comercial Pilsner (radeberger) And out of curiosity measured the ph and it was 3,90.

 

[rabeb25]

My meter has come to life again!
I brewed today and periodically checked the meter in the buffer solutions and it seemed to work just fine!
Could it just have had a bad day?

and about the 3,85; I just had a comercial Pilsner (radeberger) And out of curiosity measured the ph and it was 3,90.

That just tells you that salt water funk of a Pilsner uses an accelerated lager fermentation.

 

[ajdelange]

My meter has come to life again!
I brewed today and periodically checked the meter in the buffer solutions and it seemed to work just fine!
Could it just have had a bad day?

If it had a bad day it is going to have another. Intermittency is common in a failing electrode.

and about the 3,85; I just had a comercial Pilsner (radeberger) And out of curiosity measured the ph and it was 3,90.

I do not know what the pH of this particular beer is but it would be unusual for it to be below about 4,40. If I got a reading that low on a Pils I would definitely check the calibration (in 4 buffer).