Cooling of wort before testing:
Cooling of the wort before testing is the ideal scenario. All digital pH meters irrespective if you purchase ours or a $300 one from another supplier will have reduced probe life if you put the probe into hot wort. With that said it will not destroy the probe instantly if it gets immersed in hot wort. You will be able to do this many times until you complete destroy the probe. It just comes down to a trade off between how long you want for wort to cool down and how long you want your probe to last. I would imagine even if you immersed the probe in hot wort once a week in hot wort for 60 seconds you would still get the probe last a couple years and it still give you usable readings.
Accuracy:
Thanks for this question. This question gives us the opportunity to explain a few points about accuracy in general. With PH meter they are largely only as accurate as you calibrate and how well you keep your probe. This is not just with our pH meter but all pH meters.
Its important to remember that the accuracy of the pH meter will be determined by a number of factors including:
1. The accuracy of the calibration solution
2. The temperature of the solution
3. The pressure in the pH glass bulb
4. a long list of other factors that are too numerous to state...
With regards to 1 the buffer solution that we supply with the kit is +/- 0.05ph. So this is important to take into account. You can get more expensive buffer solutions that have higher accuracy but to be honest these are more than adequate for any home brew or commercial brewery opperation. With that said its important to understand this so I have to point it out. With regards to 2 the temperature of the solution will be a factor. Both the temperature of the buffer solution when calibrating but also the temperature of the solution that you are measuring. As the temperater gets further away from ambient you will notice that the accuraccy also will varly slightly more. The ATC will calculate out some of this error but the ideal scenario is that the wort temp is ambient temp if you want extremly accurate results. With regarsd to 3 the pressure in the glass bulb will vary with the depth and position that the pH meter is placed into the container. As these glass bulbs measure hydrogen-ion activity in water-based solutions, if we immerse the pH sensor into a soluition the hydrogen-ion activity is not even, so you will get different results even with the same sample just by moving the probe.
Previously we were reluctant to state the accuracy of the pH meter as it's something that is very difficult to determine. With that said it seems that it's a question that we are getting more frequently so we have now put this into our specification sheet and as you can see from this PDF the accuracy has been amended into this sheet as pH 0.05.
https://www.kegland.com.au/media/pdf/Ph Meter Instructions 2.pdf
In some respects the stated "accuracy" on a specifcation sheet can be misleading. Accuracy at room temperature, accuracy and the edges of the recommended temperature range, or accuracy with just water. The accuracy of a sample of water compared with beer wort will be different. So you kinda have to take the accuracy reading with a grain of salt too. What we can say is we use a high quality probe and we have a high level of resolution to read that probe. If we start the accuracy as 0.05 or 0.01 or 0.1 to be honest this number on it's own is a bit meaningless.
Now with all that said, the probes that we use are very high quality probes. We have put a very good quality probe on here and the same probe is used on pH meters that sell for 4 or 5 times the price. The accuracy of these pH meters is signficiantly better than what any brewer will need. But most of all with any scientific instrument it will only be as good as you look after it.
I challenge anyone to find a better quality pH meter any anywhere near this price, distributed and supported by a local Australian company and that supplies spare parts such as replacement probes.
