PH Samples from the Mash

[Firkin L]

I'm interested to know at what point people take their PH samples from the mash tun and what your readings are.

We are taking samples from the first runnings and last runnings however I'm getting consistently low results from my samples.

My first runnings sample taken approx 5 mins after opening the tap and before the sparge are in the region of 5.1-5.3 after being cooled to 20C using a non-ATC ph meter. After deducting .35 from the reading, you can see the mash PH is actually 4.8-5.0

My final runnings are around 5.4-5.6 at 20C SG1008. Again, taking .35 away makes this reading very low and nowhere near the upper end of the 5's as I would expect.

I would just like to clarify if most people take their samples at roughly the same time and what their cooled readings are. Our meter is a couple of years old and the probe might be on the way out because it takes quite a while to stabilise.

If your first cooled readings are 5.5-5.7 then I know I definitely need to adjust our water treatment regime or get a new PH meter! It has been calibrated by the way, using PH7 and 4 buffer solutions.

Cheers

[KWLSD]

A couple of questions/thoughts:

- Are you having problems with wort clarity/fining or stability of your finished beer?

- If your pH meter is slow to respond, it may simply need cleaning. The porous plug on the sensor tip tends to get clogged with proteinaceous material. you can buy protein remover from your supplier (or you could try the stuff from chemists for doing the same job on contact lenses!)

Regards,

[Firkin L]

A couple of questions/thoughts:

- Are you having problems with wort clarity/fining or stability of your finished beer?

- If your pH meter is slow to respond, it may simply need cleaning. The porous plug on the sensor tip tends to get clogged with proteinaceous material. you can buy protein remover from your supplier (or you could try the stuff from chemists for doing the same job on contact lenses!)

Regards,

No, we don't have any problems with clarity or fining the beer and the stability is good too. We recently had some "lively" casks but we put that down to racking them off a little quicker than we would normally.

I've cleaned the probe on the meter recently with a very mild caustic solution but I will check it more closely.

[wiredgourmet]

Have you checked the meter by measuring your buffer solutions? Try this after calibrating, and then after several uses. If it doesn't measure within 0.05 of the solution's pH, I would look into replacing it.

Can you replace the reference junction on yours? It is true they get fouled over time. Also the coating on the glass portion is delicate and can be abraded over time by cleaning/wiping if you're not careful.

If you have doubts about your meter, other issues are academic until you eliminate that as a possible problem.

[KWLSD]

If your beer's performing well with those figures - even though they may be slightly out from 'ideal' - then I wouldn't be inclined to make any recipe changes.

Better to try against another pH meter - anyone near you who would assist? Then if there's a discrepancy, even after you've thoroughly rechecked your own meter, it sounds like time to buy a new one.

[kai]

If your pH meter has a lot of drift then it might benefit from a soak in a pepsin + HCl solution to clean off the buildup on the probe from many many beer & wort samples.

At recirc our mash pH is usually 5.3-5.4 cooled.

[dick murton]

I don't understand why you are taking .35 off your pH result. Please explain

Thanks