Corrosion Issues Answered

Hello Anova Community!

This is Jeff Wu (Senior Engineer @ Anova) - I wanted to speak to some of the corrosion questions that have been asked recently.

There is absolutely no issue with the water sensor and what everyone is seeing is normal. The water sensor will discolor and people will see build up under normal usage but this is completely expected (just to reiterate again).

  1. Question: Why does the probe turn brown or black?

Answer: During manufacturing (forging, cutting, and polishing), impurities in the steel and residuals from cutting and polishing end up imbedded into probe. During the first few weeks (depending on usage) the impurities and residuals leach out (yes this is normal). This process turns the probe brown or black. After the break in period, this process will eventually stop and the probe will last forever.

  1. Question: Why is there build up on the probe?

Answer: This is a normal build up of mineral deposits mostly from tap water. Build up can be brown, black or even green depending on your water pipes and water source (if you drill your own well or use a water utility).

Please let us know if you have any additional questions about your systems. Your feedback is incredibly valuable.


Hi Jeff,

You mention the “build up” but most of posters seem to suggest that it’s actually “corrosion” (ie, a significant subtraction (or “wearing away”) of material – moreso than “some embedded impurities” would suggest).

I’m not sure if you were addressing the corrosion (as defined above) or the more general term of “stuff that happens to the probe”. Can you clarify if your answer includes the corrosion?

thanks for the update @AnovaJeff‌. Since I took those photos back in December (when my dev unit probably had 200-300 hrs on it) showing the stainless pitting on my unit in this discussion - it’s gotten worse (probably another 100 or so hours of use). So, I’m not sure I agree with your comment “During the first few weeks (depending on usage) the impurities and residuals leach out (yes this is normal). This process turns the probe brown or black. After the break in period, this process will eventually stop and the probe will last forever.” I don’t think it qualifies as just impurities “leaching out”.

@aarthur Thank you for your message, we appreciate your insight on this issue. Regarding your unit, you’d expressed interest in returning after the holidays since it hadn’t caused any issues with cooking for you at the time and you still wanted to use it. Is this still the case? The corrosion shouldn’t be altering the device functionality, although if it has please let us know and we can exchange your unit.

@jshannon Jeff’s response above is regarding the corrosion issue that you may have seen discussed in other threads on the forum. The sensor is pulling charged particles from other sources including the water, sides of your pot, particles stuck to the bag, air particles, etc. All of this is going to stick to it and cause a discoloration, which is normal and does not affect the use of the device. Does this provide any sense of clarity?

I hope this helps, please let me know if you have any further questions!

@JordanHouston‌ No. I don’t care about discoloration or even the corrosion he describes.

There have been many pictures in other threads that are clearly of pitting. As you say, Jeff’s post is in regards to stuff that’s “sticking to and causing discoloration”, which is basically the opposite of pitting, and was suspiciously silent on the issue of pitting. That’s what I’m looking for him to address.

Does he deny the pitting is happening? Does he consider what the other threads are referring to pitting to be what he describes as “corrosion”? Is it normal and acceptable? Was it a bad batch?

Good summary of the issue here by @jshannon I’m a complete layperson barely following this issue, but it is obvious that at least a few users are presenting an issue and Anova is responding to something different. Why there is a disconnect is worrisome, as it would seem obvious for Anova to directly say “There is no and will be no pitting” or “There is no and will be no corrosion” and go on to discuss why that is the case. It is unclear why the only questions answered above are about ‘build up’ or ‘brown and black’ coloration.

@jshannon and @brady747 - Thank you both for your feedback! I’ll share your concerns with the team and will share any updates with you.

While there is corrosion, the type occurring is normal and will occur in most Precision Cooker devices. This is due to the electricity charging through the probe, which is a bead-blasted 308 stainless steel that reacts this way with the 5 volt dc power supply. The corrosion will stop once it reaches the chromium layer. There are many types of corrosion and pitting has been one most of our community members have noted. While this may occur, it is important to note that there are many varieties of this type of corrosion and in this case, it is not dangerous and it will reach a stopping point.

The corrosion is not harmful, nor will it affect the functionality of the unit, however we’re more than happy to issue replacements if this occurs.

Happy to answer any other questions you may have on the subject - thanks!

@JordanHouston Most helpful response ever! Thanks for the updated information and clarity from the Anova side of things. Best wishes to you guys and keep up the good work.

@brady747 You’re welcome and thank you for your feedback!! :slight_smile: