PH Question

[FNM]

Hey all,

I've finally started using my own water for my all grain brewing. I connect a Carbon Block filter and let my water run for a few minutes, In the same way I had my water tested by Ward before I decided to use my own water and the general PH result came out at 8.1.

Now I know the mash PH is the one that matters and i'll get into treating/checking that though while i'm learning how to use the PH meter and I've only ever used Poland in the kits I make, i'm trying to just make pure water so to speak.

My question is more about procedure; I have a Milwaukee MW102. Lately I've calibrated the meter fine and poured out my mash water. It usually comes out just over 7 (say 7.2). After then pouring out my Sparge water a little later, it's been coming in around 6.7. I thought "hmm maybe my calibration is off", so I rechecked in solution and fine.

Questions:

1. Is it usual that an official water test would come out 1.5 points higher than average and for it to vary .4 points between say 90 minutes?

2. I usually take the probe out of the storage solution and rinse it with water quickly then dip. This sound the right thing to do?

The instructions lead me to believe I'm doing it right but if i'm doing something stupid i'd rather be told Note, when I re-dip in the calibration solution it registers correctly, so it looks correctly calibrated.

 

[blackonblack]

I'm not really understanding what your doing. ...

But yes the ph of the water will change during the mash. Biochemical reactions are taking place and the warm water is dissolving compounds and ions which affect ph. Throughout the sparge the ph will also change as a function of the concentration of dissolved compounds and ions which changes throughout laurering.

What kind of electrode did it include. Some are much more accurate and expensive as others.

Temperature will effect ph and some probes don't automatically adjust for this. Could this be the culprit?

Yes use tap water to rinse off the electrode from storage solution

Calibrate your probe often preferably a 2 point calibration. And store the probe in special storage solution and always keep the filament moistened . Tap water should NOT be used to store and definitely not distilled water.

 

[FNM]

Thanks for the thoughts - I'm with you if temp does change the PH, would make sense as my well water can get seriously cold the longer it runs. Stupidly enough it has a temp probe too which I should have used! (duh)

It came with the stock probe (guessing a Milwaukee one)

and seems to do a fine job when I test with the calibration solution. I was really just trying to get my head around why it'd change so much and make sure I was able to use is properly before I start testing the mash etc.

Appreciate the help!

 

[Hermit]

1. Is it usual that an official water test would come out 1.5 points higher than average and for it to vary .4 points between say 90 minutes?

2. I usually take the probe out of the storage solution and rinse it with water quickly then dip. This sound the right thing to do?

1. Yes
1.A. It can pick up carbon dioxide from the air but this sounds a bit much. I usually swish my probe around a little and don't count on the hourglass to mean the reading has stablized.

2. Yes

You should use distilled water to rinse it if you can, but not a big deal. AJ suggest blotting the outside of the probe to remove excess water. Check out his 'sticky's' in the brew science section ton pH meters.

 

[blackonblack]

I recommend rinsing with tap water not distilled water. Distilled water can quickly ruin an electrode with frequent exposure