5.25 too low?

Mashing a dry Irish stout now and am at 5.25 mash ph (room temp). Too low, or let it go? What would you do?

The first thing I would do is ask how you measured that pH. If it was with strips I wouldn't worry about it. If it with a recently calibrated meter I might be tempted to let it go because I have never had a mash pH that low and am kind of curious as to how the beer would come out. In addition to that I would look at my grain bill and water and try to figure out how it got to be so low so that I could make adjustments (reduced sauermalz, reduced dark grains, increased alkalinity in the water...) the next time I brewed it.

If I realized that I had slipped a decimal point and inadvertently and added 50 mL of hydrochloric acid instead of 5 I would then probably add some lime to get the pH a tenth or 2 higher.

I wouldn't worry about it. Its just slightly too low and I've made several beers with mash pH that low. RDWHAHB.

Thanks guys. PH was measured using my Hanna ph meter which I calibrated this morning. I ended up throwing in a tsp of chalk (don't be mad AJ!) and pH was 5.38 at the end of the mash. Here's the EZ water report if you are interested. I did a no-sparge mash with a total of just under 9 gallons of mash water. I also ground up the roast barley (1lb) in my coffee grinder until it was nearly powder. Wonder if that could make more of the grain available to reduce pH? Thanks again.

Bill


Starting Water (ppm):
Ca: 23
Mg: 5
Na: 20
Cl: 18
SO4: 39
HCO3: 58

Mash / Sparge Vol (gal): 8.8 / 0
RO or distilled %: 0% / 0%

Total Grain (lb): 11.3

Adjustments (grams) Mash / Boil Kettle:
CaSO4: 0 / 0
CaCl2: 5 / 0
MgSO4: 0 / 0
NaHCO3: 0 / 0
CaCO3: 0 / 0
Lactic Acid (ml): 0
Sauermalz (oz): 4

Mash Water / Total water (ppm):
Ca: 64 / 64
Mg: 5 / 5
Na: 20 / 20
Cl: 90 / 90
SO4: 39 / 39
Cl to SO4 Ratio: 2.32 / 2.32

Alkalinity (CaCO3): -47
RA: -96
Estimated pH: 5.47
(room temp)

You're fine.

LBA4ME said:

PH was measured using my Hanna ph meter which I calibrated this morning. I ended up throwing in a tsp of chalk (don't be mad AJ!) and pH was 5.38 at the end of the mash.

Click to expand...

I have no problem with this. My cry is "don't do it unless a pH meter reading says you need to". It did and you did and you got a near perfect mash pH at the end of the day. That's the way it's supposed to work.

pjj2ba said:

I also ground up the roast barley (1lb) in my coffee grinder until it was nearly powder. Wonder if that could make more of the grain available to reduce pH?

Click to expand...

Possible as I see nothing else to suggest that pH would be that low.

Were the buffers fresh?

Cheers, A.J.

No. The buffers I used to calibrate were old and in fact the last little bits left in the bottles.

LBA4ME said:

No. The buffers I used to calibrate were old and in fact the last little bits left in the bottles.

Click to expand...

That cast's suspicion on all your observations. When you take a pH measurement you are comparing the sample to the buffer. If the buffers are off, your measurements are all off too.

As I noted earlier it doesn't seem likely that you would have such low pH given the the water and grain bill - even with the roast barley ground up fine. Possible, but not likely.