Digital Ph meter help

[barneey]

You have to calibrate digital Ph meters before every use session as the cheap ones are notorious for drifting by miles even within 24hours

You will need some buffer solution to set them up properly.

Or you could just buy a decent one... Calibrating them is a massive faff, because the buffers are only accurate at the specified temperature.

Cheap pH meters aren't any better than the test strips really. Easier to read, but I wouldn't rely on them for accuracy. My Hannah HI 98128 was great until it died. (The O-ring sealing the pH electrode failed. Probably my fault for sticking it straight in the mash...) But that was the thick end of £80...

As a matter of interest what meter are you using now?

Cheers

[gregorach]

I ended up reverting to the narrow-range test strips for a while... I haven't been brewing much the last few months due to working too much, but I should be getting back into it soon and I've just ordered another one exactly the same. It's a perfectly good meter, I just need to be a bit more careful with it.

[barneey]

Thanks gregorach, I think if I`m going to buy one I`ll go for either the Hanna HI98127 or 28 http://www.hannainst.co.uk/Leaflets/HI9 ... eaflet.pdf if I can find one at a reasonable price, if not the strips have always worked well for me.

Cheers

[gregorach]

I've literally just ordered a new HI98128 from Hop & Grape for £75.59 plus delivery. That's the best price I've seen for it. When it comes to digital meters, I always like to get one with a resolution an order of magnitude higher than the accuracy I'm looking for (so a resolution of 0.01 for an accuracy of +/- 0.1, although the accuracy of the HI98128 is specced as 0.05). Generally, the last digit on a digital meter only tells you which direction to round in... I wouldn't trust a meter that only reads to 0.1 to be accurate to better than +/- 0.5. (Although the HI98127 does claim +/- 0.1 accuracy, and they're a pretty reliable brand.)

One thing I can attest is that these meters have stable calibration, which seems to be something that lets a lot of the cheaper meters down. (Or so people say...) It's probably worth thinking about getting a bottle of storage solution as well.

[barneey]

Regarding the liquid buffer solution for these meters, any particular makes I should look out for in terms of quality and ease of storage between uses?

I`ve seen the hanna pouches but would prefer something with its own storage vessel.

Cheers

[gregorach]

With the Hannah pocket meters, you just put a few drops of storage solution in the cap, and store the meter upright. Can't help with any particular brand - it's all the same stuff, as far as I know.

[Dave S]

I did look at that one (even watched a YouTube video of it in use) and was a little perturbed by how the figures it was registering wobbled about so much, plus there was no ATC facility and you need a screw driver to adjust and it didn't come with buffer solutions for calibration. Good price though.

Hi Orlando

It does come with buffer solutions, not much of I admit, but enough for one or two calibrations. At the price it is obviously not the best, but almost anything has to be better than the strips. To me they never seem to match exactly any of the colours on the scale.

[barneey]

Managed to get my hands on a Hanna meter, have now spent a small fortune on 1 x 500ml cleaning solution, 1 x 230ml storage solution and 2 x 230ml bottles of liquid PH 7.01 and PH 4.01, so if any of the posters in this thread are in need of a small trial amount of fluid let me know.

[orlando]

Thought I would update on my experience with the PH meter. It arrived within 10 days (can't remember exactly) and as it came with 3 sachets of buffer solution to calibrate it I think it represents excellent value. I of course have to assume it is correct but I was able to make up 250ml of solution from each sachet, which I also assume is stable over time (does anyone know how long?) so can calibrate every time I use it if necessary. It has ATC (automatic temperature compensation) so I don't have to allow for that and feel confident that I have gained another tool to help me with precision and accuracy when it comes to liqour preperation and crucially the mash.

I was able to make an offer on it when I bought this one (see above) but when looking again for the same supplier they appear to have pulled this option. It is still a good buy though, even at the current price.

Try here if interested.

[barneey]

I`ll be interested in how you get on with the PH solutions, the Hanna stuff costs £13.00 for a 230ml bottle.

One test for you meter to see how long the solutions last, is to calibrate the meter over say the 4 & 7, then actually test the third to see what the result is. If its near or spot on, no problems?

[orlando]

Fine, I've stored it in some small pots I have for storing harvested yeast (thoroughly rinsed of course). The sachets contained a sort of granular powder which you mixed with deionised water. I calibrated the meter with all 3 solutions and it appears to work brilliantly. My hope is that it accurate and I can now ensure my water is corrected properly and my mash pH is on target for every brew.

I will try your idea of calibrating with 4 and 7 and then go for a reading on 10 in a week or so.

[Dave S]

Fine, I've stored it in some small pots I have for storing harvested yeast (thoroughly rinsed of course). The sachets contained a sort of granular powder which you mixed with deionised water. I calibrated the meter with all 3 solutions and it appears to work brilliantly. My hope is that it accurate and I can now ensure my water is corrected properly and my mash pH is on target for every brew.

I will try your idea of calibrating with 4 and 7 and then go for a reading on 10 in a week or so.

One thing to note though is that the calibration power should be be mixed with distilled water, which is not the same as deionised. It has to be ph 7 in order to get the correct ph from the solution.

[orlando]

I just followed the instructions, which called for deionised.

[Dave S]

I just followed the instructions, which called for deionised.

That's interesting, because deionised just has electrical charge removed, whereas distilled has all particulates removed rendering at neutral ph. It is amazing though how many people think they are the same.

[Martin G]

Just followed a link from another thread. I don't think deionised water has only had the charge removed, I think it has had the mineral ions removed, which are important for pH.