post-fermentation pH

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akardam

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pH 3.85 post fermentation is okay? pre-fermentation (after boil) pH was 5.5. in 9 days SG went from 1.068 to 1.007. tastes great though, even though i had an impression it was a bit acidic..
if its too low, what should i do? haven't bottled yet..
thanks for any help..
 
I've never heard of measuring "post-fermentation" pH of beer. In fact, I've never heard of measuring any pH aside from the mash. It looks like you got very good attenuation, and at 7.71 abv, you're probably just tasting green, hot (moderately high alcohol) beer. I'm sure it will get right in the bottles. Give it some time...
 
3.85 post fermentation is pretty dang low. 5.5 post boil is pretty dang high, on the other hand. I would venture to guess that your method of measurement leaves something to be desired.
 
ok thanks for info! @reelale, I try to monitor pH fluctuations during each major step of brewing process, i.e. post-mash, pre-ferm, post-ferm and once after beer was ready for drink.. just want to identify any potential flaws (sources of oxidation) during these stages. cheers!
 
pH 5.5 post boil and pH 3.85 post ferment seems about right. See the chart at:
http://corrosion-doctors.org/Food-Industry/Beer-corrosion.htm#acidity

5.5 would imply a pre-boil pH of something like 5.7 which is acceptable but I am not aware of a source that would call that optimal.

PH < 4.0 for finished beer (not sour) is not something I have observed personally or in literature as being terribly common.

At the end of the day, when you want to know about beer pH don't go to corrosion-doctors.com.
 
At the end of the day, when you want to know about beer pH don't go to corrosion-doctors.com.
First, why not? They service the food industry.

Beyond that, though:
http://www.murphyandson.co.uk/FAQs/FAQ_Topic20.htm
http://www.murphyandson.co.uk/FAQs/FAQ_Topic11.htm
http://www.newton.dep.anl.gov/askasci/chem99/chem99214.htm
http://www.probrewer.com/vbulletin/showthread.php?p=50158 especially Dick Murton's post.

The "Brewer International" (www.ibd.org.uk/cms/file/312) cites these values:
Mash pH 5.6 ±0.2
Boiled wort pH 5.4 ±0.2
At end fermentation pH 4.0 ±0.2

akardam's values fall within these ranges.
 
Thanks guys you've been very helpful! @JohnMc, your references are exactly what I needed, thanks mate!
 
First, why not? They service the food industry.

Beyond that, though:
http://www.murphyandson.co.uk/FAQs/FAQ_Topic20.htm
http://www.murphyandson.co.uk/FAQs/FAQ_Topic11.htm
http://www.newton.dep.anl.gov/askasci/chem99/chem99214.htm
http://www.probrewer.com/vbulletin/showthread.php?p=50158 especially Dick Murton's post.

The "Brewer International" (www.ibd.org.uk/cms/file/312) cites these values:
Mash pH 5.6 ±0.2
Boiled wort pH 5.4 ±0.2
At end fermentation pH 4.0 ±0.2

akardam's values fall within these ranges.

He is at the high end of the range for post boil pH and the low end of the range for finished pH. Wouldn't you wonder why?
 
In fact, I think I am on the upper range because I didn't sparge correctly. What I did was I took my pot where I mashed for an hour, then I drained the syrup from the pot to the boiling kettle. I then filled up the 'mash' pot where the grainbed was with sparge water (at 75C) and then left it there and drained it after 10 minutes. SO, I'm thinking I lautering too fast hence resulting in a higher pH. I think I saw this relationship between lautering rate and higher pH values in Palmer's book somewhere. Now, I did another batch with a proper insulated mash tun. And did the sparging by the book, i.e. slowing draining wort from the drain at the bottom of mash tun and adding a litre of sparge water, for every litre of wort I got, at the top of the mash tun.. so to keep story short, I nailed a post-boil pH of 5.2 head on! So maybe all this is because of sparging incorrectly.. hmm.. what do you think?
 
He is at the high end of the range for post boil pH and the low end of the range for finished pH. Wouldn't you wonder why?

Depending on a whole bunch of factors, such as yeast strain, mash conditions, water chemistry, measurement accuracy, estimation accuracy and so on, not so much. pH is only a measurement of acidity, not buffering capacity. pH can be high or low but change rapidly if there isn't much buffer. None of the numbers were alarming.
 

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