Safe to drink boiled water from hot tap?

[Andy Hall]

That depends on where you shop.

I'm sure that that's true. Do they have to add calcium salts to buffer it back up to a reasonably pH neutral level?

[Tom Anderson]

Depends on the protein - there's quite a variation in denaturation temperature, and it depends on the chemical environment etc. 60-odd degrees is in the right area, though.

That's because that's the sort of temperature where collagen denatures, becoming gelatin, which is how cooking softens meat. I believe collagens from different kinds of animals have different conversion temperatures - i ISTR 58 C for fish and 65 C for mammal meat.

tom

[Dave Fawthrop]

|On Sat, 6 May 2006, David P wrote: | |> On 06 May 2006, Dave Fawthrop |> wrote: |>

|>> On Sat, 06 May 2006 00:34:13 +0100, The Natural Philosopher |>> wrote: |>>

|>> |Raising the water to 60 C kills about 95% of the bugs in seconds. |>>

|>> That temperature is actually *82* deg C to kill food poisoning bugs |>> Some food poisoning bugs breed nicely below 64 deg C |>

|> I think amino-acids/proteins get denatured (and becoma deformed beyond |> use) at about 62 degrees. | |Depends on the protein - there's quite a variation in denaturation |temperature, and it depends on the chemical environment etc. 60-odd |degrees is in the right area, though. | |> I thought that was the basis for saying that food (eggs, meat, etc) must |> be cooked over approx 62 C. | |That's because that's the sort of temperature where collagen denatures, |becoming gelatin, which is how cooking softens meat. I believe collagens |from different kinds of animals have different conversion temperatures - i |ISTR 58 C for fish and 65 C for mammal meat.

I am not disputing your protein denaturing figures, it is just that bacteria are not just protein, but a lot tougher. Some will withstand greater than 100 deg C and even breed at that temp.

10c. Hyperthermophilic Archaea.

Temperature for growth(degrees C) Genus Minimum Optimum Maximum Optimum pH Sulfolobus 55 75-85 87 2-3 Desulfurococcus 60 85 93 6 Methanothermus 60 83 88 6-7 Pyrodictium 82 105 113 6 Methanopyrus 85 100 110 7

Figure 8. Sulfolobus acidocaldarius is an extreme thermophile and an acidophile found in geothermally-heated acid springs, mud pots and surface soils with temperatures from 60 to 95 degrees C, and a pH of 1 to 5. Left: Electron micrograph of a thin section (85,000X). Under the electron microscope the organism appears as irregular spheres which are often lobed. Right: Fluorescent photomicrograph of cells attached to a sulfur crystal. Fimbrial-like appendages have been observed on the cells attached to solid surfaces such as sulfur crystals.T.D. Brock. Life at High Temperatures.

[Chris Bacon]

Iron pipes were used extensively. I'd be surprised if they were used only 40 years ago, though, because plastic/copper was normal.

[Dave Fawthrop]

| |>

|>|>The only Life without risk is death. |>| |>|Of course, so why spoil it with foul tasting tap water? |>

|>Our tap water straight off the Yorkshire peat moors tastes fine. | |I'm sure that that's true. Do they have to add calcium salts to |buffer it back up to a reasonably pH neutral level?

They used to stop the lead pipes dissolving, not sure about now.

[Owain]

It'll be cheaper than buying Irn Bru

Owain

[Helen Deborah Vecht]

Tom Anderson typed

I doubt it; the clostridia are anaerobes and don't tolerate air very well. Down in the soil, they are almost universal.

You probably have them in small, manageable numbers in your healthy intestines anyway. (Please wash hands after using the WC. It is more important to physically remove muck than to apply antiseptics in normal situations.)

[The Natural Philosopher]

Not from drinking contaminated water though.

Last weeks Tesco's pork pie is far more dangerous.

[The Natural Philosopher]

something rather than a dead sheep wedged in a stone wall?

Somehow I think you have fallen for a false sense of freedom.

I suggest you actually carry out tests, or find someone else to, on bottled water.

>

[The Natural Philosopher]

[Andy Hall]

No need.

[David Hansen]

On Sat, 06 May 2006 13:37:02 +0200 someone who may be Mxsmanic wrote this:-

Iron surfaces in contact with water that will be drunk from the hot tap. Hmmmm. Can't think of that many in UK plumbing, other then any old-fashioned direct hot water systems (including the ones with the old square hot water tanks). I imagine there are a few of these left in the UK, but not many.

And what sort of heater is that?

[David Hansen]

On Sat, 06 May 2006 13:40:17 +0200 someone who may be Mxsmanic wrote this:-

If it is under pressure in a very old iron tank then the tank could well fail at any time and, as others have said, replacement should be a priority.

[John Savage]

It probably depends a lot of the water's pH and natural mineral and gas content, but around here it is recommended that when preparing beverages we use water from the cold tap. My understanding is that copper dissolves better in hot water, so water that has been standing in the hot water tank emerges with a higher copper content than water that has been standing for equal time in cold copper pipes.

To avoid unwanted copper intake, fill your electric jug from the cold water tap even though it will take a minute more to bring to the boil.

-- John Savage (my news address is not valid for email)

[Dave Plowman (News)]

And the extra time taken dissolves nasty chemicals from the kettle body?

First I've heard of copper dissolving in hot water. How long does it take for the pipes to disappear?

[John Savage]

No one knows; we throw out the HWS as soon as one tiny spot in the copper coils corrodes all the way through. Wasteful innit?

The time this takes varies a lot with what's in the water you feed the system. 30 years for rural rainwater, 8 years for caustic acid rain. But you'll notice that cold water pipes of similar gauge are set to last for centuries.

Copper dissolves in cold water too, but more will dissolve in hot. If you regularly drink tap water from a building tap that has not had water running through the pipes for days, it's best to first run off some to clear the copper piping of water that has been stagnating there for a long time. Even the cold water pipes.

-- John Savage (my news address is not valid for email)

[Dave Plowman (News)]

But often caused by impurities in cheap tube?