pH meter probe life expectancy

[flanken]

I've been doing a lot of hemming and hawing about purchasing a new pH meter, especially after seeing that the MW102 is on sale for $85 + s/h...

My biggest hang-up is probe life expectancy.

The MW102 has passed the HBT quality test, and the unit comes with a 2 year warranty, but the probe itself is only covered for 6 months under warranty.

I've been brewing a couple years now but only just made the switch to AG. I have a 3.5 year old and a 1 month old so I can go a few months between brew days.

It seems like every meter requires probe replacement at some point, and the cost is often 40-60% of the total cost of the meter. That's fine if I can expect it to last a couple years, but not fine if they only last 12 months or less (maybe only 3 or 4 brew days).

How long are you all able to keep your pH meter probe alive and accurate, and what are your recommendations for doing so?

And is pH probe life more a function of time or usage?

Brian

 

[ajdelange]

Short electrode longevity was enough to keep pH meters out of the hands of home brewers until fairly recently. The picture is now much better than it used to be with even the cheap electrodes lasting 2 years or more in many cases but the fact that the warranties on them is still short tells you that the luck of the draw is still part of the equation. I have a pH electrode that will not die. I've been using it for over 5 years and while it is getting as bit sluggish its slope is still 98% and its offset only a couple of mV. Its isoelectric pH is, however, over 8 and has been so for at least 3 years. I'm getting at least 3 years on other electrodes (less expensive than this seemingly immortal one but still more expensive than most of the meters discussed here). The electrode in my Hach Pro+ will be (I think) 3 yo this fall but I don't use it much.

I would have to say that I think the chances of 2 years of life are quite good but that there is a chance that it will be less than that and there is a chance that it will be more than that. What I'd like to be able to give you is an expected lifetime but I can't.

Certainly how you use the electrode and how you store it are factors. Always store following the manufacturer's recommendation. Brewing imposes some tough requirements because of the presence of sugars and proteins so keeping the electrode clean with an enzymatic cleaner seems a good practice but to be honest I don't recall doing that for quite a while and I take lots of pH measurements of mash.

Probably the most important thing is to avoid temperature shock which means cooling wort and mash samples before measuring.