pH meter

[beer today]

thinking about getting a pH meter.
Anyone any advice, on brand, calib, costings, effectiveness.
cheers
bt

[Belter]

Everyone seems to rave about the Voltcraft. I have the Hanna HI98127 and love it but it's more expensive and the resolution isn't as good as the Voltcraft. Also replacement probes are more expensive for the Hanna.

[Dave S]

Everyone seems to rave about the Voltcraft. I have the Hanna HI98127 and love it but it's more expensive and the resolution isn't as good as the Voltcraft. Also replacement probes are more expensive for the Hanna.

+1 for the Voltcraft. Had one for over a year. It's the ATC100 PH and you can get it from Conrad Electronics for around £40. Replacement probes are about £20, though I haven't neded to replace mine yet. I get my calibration solutions from Amazon for under £10 for 2, (pH 4 and pH 7).

[Aleman]

I use an Oakton pH5 which comes with solutions and case. One button calibration . . resolves to and is accurate to 0.01 pH units . . .although in reality unless you are in a lab that level of accuracy is very misleading


Also doubles as a reference Thermometer.


Comes at a price however

[Dave S]

I use an Oakton pH5 which comes with solutions and case. One button calibration . . resolves to and is accurate to 0.01 pH units . . .although in reality unless you are in a lab that level of accuracy is very misleading


Also doubles as a reference Thermometer.


Comes at a price however

You're right, it does come at a price. Think I'll stick with the Voltcraft , resolution - 0.01, accuracy - 0.07 which, provided it's calibrated before each use is good enough for our purposes. I do recall another thread recently pointing to another low cost one claiming 0.01 accuracy. Can't remember what make it was now.

[stibnite]

[quote="Dave S"][quote="Belter"]Everyone seems to rave about the Voltcraft. I have the Hanna HI98127 and love it but it's more expensive and the resolution isn't as good as the Voltcraft. Also replacement probes are more expensive for the Hanna.[/quote]

+1 for the Voltcraft. Had one for over a year. It's the ATC100 PH and you can get it from Conrad Electronics for around £40. Replacement probes are about £20, though I haven't neded to replace mine yet. I get my calibration solutions from Amazon for under £10 for 2, (pH 4 and pH 7).[/quote]

How does the voltcraft do temperature compensation? the image only shows a BNC connector for pH so do you have to manually enter the temperature?

The Hanna one will be better as it has built in temperature and digital calibration but it is significantly more expensive

edit oops dont know what happened to the quotes

[Dave S]

I never rely on the temperature compensation, it only compensates for temperature changes in the instrument, not temperature changes in the sample. I find it better to let the sample cool to the temperature I calibrated at - usually 20-25C.

[Aleman]

I never rely on the temperature compensation, it only compensates for temperature changes in the instrument, not temperature changes in the sample. I find it better to let the sample cool to the temperature I calibrated at - usually 20-25C.

Should be 20C . . . I keep a set of shot glasses in the freezer, take a sample transfer to the shot glass and take the reading. It has generally cooled to be close to the calibrated Temperature , if not it only takes around 30 seconds to cool.

[Dave S]

I never rely on the temperature compensation, it only compensates for temperature changes in the instrument, not temperature changes in the sample. I find it better to let the sample cool to the temperature I calibrated at - usually 20-25C.

Should be 20C . . . I keep a set of shot glasses in the freezer, take a sample transfer to the shot glass and take the reading. It has generally cooled to be close to the calibrated Temperature , if not it only takes around 30 seconds to cool.

Good idea, I've often pondered the use of sample reading if you have to wait close on an hour for it to cool, by which time there's isn't any point in adjusting the mash pH if it's out. What I've done in the past is bung the sample in the fridge, but it still takes a while. Will try your method next time.

[beer today]

Voltcraft it is then, thanks chaps. Be interesting to see how acomparitive brew turns out, as my last one appeared to be 5.3 according to the paper strip.
cheers

[Belter]

I was just reading from Graham Wheeler and reminded mysel of reading the same thing in the water book. The difference in pH between wort at mash temp and 20C is about 0.1. Not enough to concern us if we're within the ideal PH range.

I've found this to be the case when measuring a sample at about 40C and then cooling it to 20C.

Obviously it isn't good for your delicate probe to subject it to extremes in temperature but it saves waiting until your sample is exactly 20C

[fego]

I've often pondered the use of sample reading if you have to wait close on an hour for it to cool, by which time there's isn't any point in adjusting the mash pH if it's out.

How do you adjust the mash PH once you've discovered it's out?

[Aleman]

I've often pondered the use of sample reading if you have to wait close on an hour for it to cool, by which time there's isn't any point in adjusting the mash pH if it's out.

How do you adjust the mash PH once you've discovered it's out?

You don't you make a note of what it is this time, what treatments you used and the grain bill , and adjust it for next time.

Technically if the pH is too high you can add acid to the mash and stir like crazy, remeasure and hope that it's in the right place. If it's too low you can add calcium carbonate or sodium hydrogen carbonate and stir etc. . . As the mash is a self buffering state, it really is too easy to add too much with no change . . . and then Bang, you've gone too far the other way . . . and you start chasing your tail. It's much easier to leave it alone and make the changes for the next brew.