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Old 02-22-2008, 01:08 PM   #31
mrkristofo
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Quote:
Originally Posted by deathweed
Ok, its been awhile since I have done analytical chem, but based on some rough calculations, here is what I got:

5.2 is pH 5.2 in 1%solution (according to MSDS)
[H+]=6.31E-6

working through I got a values at:
a0=8.78E-4
a1=.989
a2=9.93E-3
a3=7.06E-10

so 5.2 is aprox:
98.9% NaH2PO4
1% Na2HPO4
~0.1% H3PO4

Meaning a tablespoon full per 5 gal=
tablespoon=15ml
MSDS said 5.2 is 1g/ml so 15g
winds up being:
124mmol NaH2PO4
1.06mmol Na2HPO4
0.15mmol H3PO4

As far as bicarb ion, 459ppm in 5 gal (18.9L) works out to be:
142mmol


hummmm, I am going to have to work on this some more, this may turn into a weekend thing.... I am not even taking into account everything else in our water, let alone how the bicarb affects the buffering capacity, because if it is at 5.2, most of the bicarb will be shifted back to its carbonic acid form... ok I am going to stop thinking about this for awhile, mabey I will spontaneously remember how to do stuff like this.
Ugh. As if I didn't have enough math to do today already. I'll give er a swig, too, but it's also been a couple years since I took analytical.
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Old 02-23-2008, 12:38 AM   #32
Dr_Deathweed
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I went through, figured everything up with the 5.2, worked out the concentrations, thought I had a buffering capacity worked out.... then realized I had forgotten to work in the water profile... oh well. Ive got the ground work laid, I guess I will finish up tomorrow.

I did get a pm pretty much stating that since our sodium is so high, adding more with 5.2 (which is a sodium/phosphate salt) may not be as good an idea as we thought. Instead, since our calcium and sulfate levels are low, using CaSO4 to lower the pH as well as lactic acid. Unfortunately calcium and phosphates tend to precipitate out, so using CaSO4 and 5.2 together won't go over so well.

Any thoughts on this? I think at this point the practical thing is just dilute our tap with RO like Lil' Sparky suggested. However, from an academic stand point, whats a good water profile for good all around brewing needs, and how to get there from the profile listed above.



and a update, tried that newcastle again, and its not near as bad as it was before. so 3-4 months wasn't enough but 1 more week might make it salvageable... Go figgure....

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