NTC "stc" probes are not wort proof.

[elcarter]

Howdy,

Been using STC probes for some time now. They are usually sold with units that are to be used as aquarium water sensors such as the STC-1000's.

I've been using them inside fermenters and inside HERMS "wort liquid" for some time and can now say without a doubt they will fail when used in this manner.

I suspected they would fail but no one really had documented the results of prolonged use. That I could find anyhow.

If they were in aquariums with close to neutral Ph and low temperature fluctuations (as they are intended) the longevity no doubt may be much longer.

Not a post to say don't do it. I have with good success and accuracy, with most lasting more than 6 months but I can now with certainty say they will fail. Just keep an eye on them the tell tail is minor fluctuations around the .1 degree decimal and gets worse very quickly.

Last HERMS probe was out by 32.3 degrees within minutes of failing.

So buy a few spare ones if you use them in this manner.

 

[seamad]

I've used 2 in my fermenting fridges directly in the wort for years without failure. I'm sure there could be problems in a herms situation because of the heat and possibly the rate of change has an effect as well, but I haven't used them in this way.

 

[joshF]

I've used mine for nearly 3 years inside the fermenter during fermentatino and it's still 100% accurate. Tested it this morning by comparing it to a rather expensive digital food thermometer. HERMS may be a different story due to the heat like seamad said, but when used in conjunction with an STC-1000 for maintaining fermentation temperature they are brilliant. I have no reason to suspect or expect it to fail any time soon when used in this manner.

 

[Yob]

Mine in my herms has been faultless for years, it's possible he just got a brummy one.

 

[indica86]

Mine went to 75 today.
Also went to -14 two days ago,
Pretty happy and certain that it went where it was supposed to.,

 

[elcarter]

Yob I wish it was so but I'm not commenting on just one or two probes failing, it's 5 I think now.

Nor from the same batch. Not the same style either. The completely coved polyurethane type is still working to this day. The stainless versions are the worst for it.

3yrs is a decent effort I hope it continues for a hell of a lot more

 

[squirt in the turns]

Slightly OT: I have a stainless corny keg dip tube which I already cut and got brazed closed, ages ago, with the intention of using it as a thermowell for an NTC probe, in the fermenter. I don't use it as I now know copper (and prob zinc or whatever else is in the brazing alloy) is not safe in beer.

If I re-did it using silver solder (lead free), would that be safe for use in beer?

Or just stick the NTP probes straight in the wort and if they fail replace? They're not exactly expensive.

 

[Pogierob]

Yob I wish it was so but I'm not commenting on just one or two probes failing, it's 5 I think now.

Nor from the same batch. Not the same style either. The completely coved polyurethane type is still working to this day. The stainless versions are the worst for it.

3yrs is a decent effort I hope it continues for a hell of a lot more

same stc?