[brewinhard]

So the results are in.  I tested the 4.00 calibration buffer, a degassed coors light, my black IPA degassed, and a pilsner I brewed degassed:

Calibration buffer = 4.05 (not perfect, but accurate enough for these purposes)
Coors light = 4.11
Black IPA = 5.55
Pilsner = 4.36

These results just confuse me even more and I have no idea what to make of them.  I'm starting to think about the fermenters that I used for each beer.  The pale ales were fermented in a couple of my better bottles, the IPA in a 10 gal corny keg I just recently acquired, and the Pilsner in my 6 gal glass carboy.  I'm starting to question my better bottles because when I first started brewing I left PBW in them and let them sit outside for a very, very long time (months).  The 10 gal corny keg, which was not in great condition when I got it, I cleaned as thoroughly as I could but maybe it was not good enough.  I can't think of any reason my glass carboy would give me any problems, and that ph seems to be right where it should be.  Is there anything potentially in these fermenters that could have caused the spike in ph?

So I am confused here.  You are telling us that your mash pH's are within an acceptable range 5.3-5.5.  Yet your reading on your degassed fermented black IPA is 5.5?

[HoosierBrew]

Yeah a reading of 14 ppm isn't a problem at all.  That's really typical of store bought RO water, which I use all the time.  You're just going to need to start eliminating variables through controlled substitutions.  I'd start with the water source.  Most Walmart stores have a RO machine in the grocery dept.

+1.  I use RO water at that TDS level all the time - it's typical and fine. My understanding is that RO systems reduce TDS at a level proportional to the source water. In other words, in an area with harder water your home system might produce water slightly higher in TDS but be fine. I avoid using RO above 25ppm TDS to reduce the (slight) contribution in mineral content. I prefer a lower rating but make perfectly good beer with water at or under 25ppm.

[MoreHops]

So the results are in.  I tested the 4.00 calibration buffer, a degassed coors light, my black IPA degassed, and a pilsner I brewed degassed:

Calibration buffer = 4.05 (not perfect, but accurate enough for these purposes)
Coors light = 4.11
Black IPA = 5.55
Pilsner = 4.36

These results just confuse me even more and I have no idea what to make of them.  I'm starting to think about the fermenters that I used for each beer.  The pale ales were fermented in a couple of my better bottles, the IPA in a 10 gal corny keg I just recently acquired, and the Pilsner in my 6 gal glass carboy.  I'm starting to question my better bottles because when I first started brewing I left PBW in them and let them sit outside for a very, very long time (months).  The 10 gal corny keg, which was not in great condition when I got it, I cleaned as thoroughly as I could but maybe it was not good enough.  I can't think of any reason my glass carboy would give me any problems, and that ph seems to be right where it should be.  Is there anything potentially in these fermenters that could have caused the spike in ph?

So I am confused here.  You are telling us that your mash pH's are within an acceptable range 5.3-5.5.  Yet your reading on your degassed fermented black IPA is 5.5?

yep that's exactly what my ph meter is telling me

[brewinhard]

I can't even think how to explain this one.  Although I feel like someone else on here was just posting something like this recently. Maybe it was on the Brewing Network?

[narvin]

The only thing I can think of is that there's some serious residue of something alkaline in your kegs or something else it comes in contact with post fermentation.  Have you tested a sample out of the fermenter?

[hopfenundmalz]

The only thing I can think of is that there's some serious residue of something alkaline in your kegs or something else it comes in contact with post fermentation.  Have you tested a sample out of the fermenter?

Residual PBW?

[MoreHops]

The only thing I can think of is that there's some serious residue of something alkaline in your kegs or something else it comes in contact with post fermentation.  Have you tested a sample out of the fermenter?

Residual PBW?

The latest batch was fermented in the glass carboy and the black IPA in a 10 gal corny which i bought recently...only the better bottles would possibly have the residual PBW