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Posted

I have a steamer I use to boil water when I boil all the water out of the pot a black residue is left. What would be the possibilities of what the residue is?

Posted

Also if the water is placed into a plastic bottle and refrigerated it turns a light green color.

Green is an indicator of copper. What material is the pot made of? What is the source of your water?

Posted

It is tap water from my new apartment. The pot is stainless steel.

Could be stuff in the lines from non-use after the last occupant vacated. Many water supply lines are copper. Also, many cities publish water quality test results that tell what all is in the water. You might check with other apartment dwellers to see if they have similar pot staining.

Posted

I got the water tested for bacteria and got <1 colony forming unit per 100ml of E.Coli, Enterococci and Clostridium perfringens

Bacteria is not likely to leave a residue. Again; check with your neighbors.

Posted (edited)

Also if the water is placed into a plastic bottle and refrigerated it turns a light green color.

What happens if you put a bottle of it on the window sill in sunlight?

Where is the water coming from?

Edited by Robittybob1
Posted (edited)
What happens if you put a bottle of it on the window sill in sunlight?

I can check.

 

Where is the water coming from?

 

My new apartment is at the water treatment facility and the water is pumped from a river's source. The apartment block is fairly new (constructed within the last eight years) and copper wasn't used in the building's pipes. The facility itself is old and completely automated and I don't know if copper was used in the water treatment facility.

Edited by fiveworlds
Posted (edited)

The material is likely borne in suspension in the water.

 

Since it is black after dry heat it could be carbon from particles of poorly deburred plastic pipes and fittings. (you said they were relatively new)

 

Manganese (as robittybob noted but I would hope it isn't) would indeed leave a black residue, as would copper oxide.

 

If the area is fed from old iron pipes then iron oxide could be transported into your new pipes.

 

Can you not complain to the water quality department of your water supplier?

 

Finally do you have any tanks in the system where sediment could collect/have collected?

Edited by studiot
Posted (edited)
Since it is black after dry heat it could be carbon from particles of poorly deburred plastic pipes and fittings. (you said they were relatively new)

 

The pipes to the treatment facility from the river are definitely plastic. I also said my building was fairly new and I live about a 4 minute walk from the water treatment facility and I don't know how old it is but it is completely automated and I never see people go anywhere near it.

Edited by fiveworlds
Posted

Can you point to picture of what your steamer looks like? Acmes' suggestion is the way to go really. If the facility is automatic, something may be amiss that end.

Posted (edited)

Is it a pressure cooker; does it have a lid with a valve in the middle? Do you just boil water in it; nothing else goes in the pan?

Edited by StringJunky
Posted
Is there any possibility it's carbonised/carbonising oil resides from past cooking sessions? Grease films - from not rinsing in very hot water after normal washing - are invisible until you heat them again and may turn black.

 

It's possible all I cook in it is potatoes though no oil or anything like that. Potatoes aren't all that greasy.

Posted

I have idea how to check whether issue is in your tap water: buy water in shop and try it instead.. ;)

f.e. distilled water in electronics/car equipment shop.

Posted (edited)

It's possible all I cook in it is potatoes though no oil or anything like that. Potatoes aren't all that greasy.

No, they aren't but they are starchy and can stubbornly cling to the pan in a virtually invisible film. When you tip the boiling water out the heat in the pan dries the starch hard. When you think about it, starch used be used as a glue. Needs to be treated the same as oil residues although it can be more stubborn. It could be carbonising starch particles.

Edited by StringJunky
Posted
No, they aren't but they are starchy and can stubbornly cling to the pan in a virtually invisible film. When you tip the boiling water out the heat in the pan dries the starch hard. When you think about it, starch used be used as a glue. Needs to be treated the same as oil residues although it can be more stubborn. It could be carbonising starch particles.

 

But I get black scale in my kettle too. The kettle was already in the flat when I got here and it has dyed the inside of the kettle (normally white) a light brown color that will not come off.

Posted

But I get black scale in my kettle too. The kettle was already in the flat when I got here and it has dyed the inside of the kettle (normally white) a light brown color that will not come off.

Right. I'm playing "Twenty Questions" with you trying to help you fathom it. :) That avenue's off then.

Posted

But I get black scale in my kettle too. The kettle was already in the flat when I got here and it has dyed the inside of the kettle (normally white) a light brown color that will not come off.

That sounds like some mineral in the water rather than organic if the stain will not come off.

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