Limescale in fermenter?

[staplefordbill]

One section of my FV has a thick coating of a white chalky substance. I assume it is limescale, calcium carbonate, call it what you will. I live in a hard water area and use bleach and VWP to clean the FV. What's the easiest way to get rid of it? Acid-based presumably?

[GrowlingDogBeer]

Ive had this in a fermenter as well, it was when I was using VWP. I don't think its limescale, I think its to do with the cleaner.

[staplefordbill]

Did you manage to remove it Steve? Don't want to scrub too hard and scratch the bucket.

[GrowlingDogBeer]

No, I never got it out, bit to be honest I never really tried.
I had just bought mango chutney bins to use and I was cleaning my fermenter ready to use as a bottling bucket. I left it soaking for a couple of days in either VWP or bleach, it may have been bleach actually as I had just had an infection in it. I then ended up with some white limescaley powder on the inside of the bucket. I was assuming it was the fault of the cleaner being left to soak.
I really should try to get it clean as until I do I can't bottle.

[Kev888]

I had a similar happening with my demijohns when I soaked them in bleach for too long; the verdict seemed to be that it was limescale and that acid was the answer; I used citric acid and it worked well but potentially I guess others may work, such as starsan, vinegar etc. (though work out the economics first - I spent more on citric acid than the DJs were worth!)

However, I also had a similar type of deposit in a corny once when I used too much of a cleaner that a home brew shop mixed up themselves; I don't know what was in it but they said it was VWP-like. That one rubbed off easily enough with a non-stick safe scrubby but I'm not sure if that'd be gentle enough for plastic.

Cheers
kev

[staplefordbill]

I'll try some vinegar then. Thanks guys!

[Graham]

In staplefordbill's case, when cleaning using stuff like sodium carbonate or sodium percarbonate or proprietary cleaners that include such things in their formulation, you are shoving lots of carbonate into the water. In hard water areas this forces the calcium carbonate (chalk), to precipitate due to a phenomenon known as the common ion effect. The white film that remains afterwards is just chalk. It is difficult to rinse off because it has poor solubility in already hard water. It is harmless, but an acid rinse, such as a spray with vinegar or citric acid will get rid of it. It is okay to rinse afterwards should you feel the need to remove the acid without fear of putting a film back.

In Kev888's case, the demijohn's were probably damaged by the sodium hydroxide (caustic soda) that is present in standard bog bleach reacting with the glass to produce sodium silicate. This causes a frosted effect. I have done the same thing with demijohns myself. It is harmless, but I don't think that it is reversible (I didn't try). It is a very slow reaction, but it is best not to let a bog-bleach solution stand in glass for exceptionally long periods and to always rinse afterwards. Alternatively, use bleach tablets for disinfecting glass, they do not have any caustic soda in them.

[Kev888]

Interesting Graham, many thanks! In my case the acid definately did reverse it, but thats probably not very useful info as I don't actually know for certain if it was sodium silicate (or some other kind of deposit).

Cheers
kev