Silly question. I've been told not to use the hot water from the sink in cooking. And recipes all...

[TreasonousBastard]

seem to start with a pot of cold water .

So, why not use the water that's already hot? It came in through the same pipes and only made a quick detour through the water heater.

[pdxflyboy]

1. I think that some hot water heaters

Put lead in the heated water.

[Warpy]

19. Big tanks also can grow bugs in the pipes and concentrate minerals

Around here, one of those minerals is arsenic, so it's cold water for me.

I'm just glad I can use it out of the tap for cooking. I've lived in one place where I needed a water service for that, 5 gallon carboys with hand pumps on the top. Using cold water to heat on the stove is not an inconvenience by that standard.

[cachukis]

2. Because it has been in a vat that has lots of schmutz

sitting on it's floor getting stirred up when you turn in the faucet. That's why.

[OAITW r.2.0]

5. Huh, I was told by a plumber that it was smegla.

[cachukis]

10. Smegma.

Had my students on the spot with their repetitious vulgarities. Had the large dictionary on a stand that everyone was expected to use as needed. I would use some Shakespearean like oaths and tell them that the construction of such was in that book. One young lady said where? and I said the first letter was s. She looked frustrated after a minute and asked for a clue. Second letter is m. Jumped forward in the book. Okay., what's next, after no hit. E. Moments later, SMEGMA! Reread it and said ooouh. Then I caught the clicking of gears. She would learn to cuss with style.

[ramblin_dave]

3. Some info...

https://gykam.com/life-insurance-marketing-tools/the-dangers-of-using-hot-tap-water-for-cooking-and-drinking-1545253415639.html

[elleng]

8. Oh right!

'Using hot tap water for drinking or cooking is a no-no, the Environmental Protection Agency warns. That’s because hot tap water can leach harmful contaminants like lead from your home’s service pipes into the water you might be drinking or using to prepare hot foods. The safest bet is to always use cold tap water when drinking and to start with cold water when preparing hot foods or drinks.

Lead dissolves easier in hot water, and too much of this heavy metal at any level can cause serious damage to the brain and nervous system. Even boiling the hot tap water doesn’t remove the lead but only makes it more concentrated if it’s present to begin with. Children and pregnant women are most at risk for developmental issues, yet lead exposure in adults can cause joint pain and high blood pressure.'

[zipplewrath]

12. Old houses

Most of these dangers are only going to be for older houses. The use of lead in plumbing ended long ago. Huge portions are plastic. Some is still steels of various sorts.

[mobeau69]

18. Copper is the best material for water supply and has been used for years. It is now, due to cost,

only used for commercial and high end homes unless specified by a knowledgeable buyer. One caveat though-until about 25 years ago, except for California, it was used with 50/50 solder and fittings that contained some amount of lead. Recently constructed homes required and new homes nationwide require lead free solder and fittings.

PEX (crossed linked polyethylene) is the popular choice today for builders wanting to keep costs down and for DIY’s afraid of their lack of skill in soldering. PEX looks great as an alternative until one learns about it’s history of stress fracturing which has resulted in litigation for its manufacturers who in turn blame failures on aggressive water.

[BarbaRosa]

4. Cold water is fresher.

[Ferrets are Cool]

6. I guess I'm gonna die any minute now

because for the last 64 years I've been using hot water from the water heater to cook with. Should I go ahead and write my obit?

[elleng]

9. Please write one for me too, SOON,

I'm OLDER than you!!!

[mike_c]

7. The folks at Cooks Illustrated tested this a few years ago.

Their results were that it didn't matter at all, at least not in the sense of impacting the taste of prepared food. Blind testers were not able to detect any difference in dishes prepared with cold water and hot water. I believe that included brewing coffee.

[Cozmo]

11. I guess this is a general observance and not related to an exact ingredient to be cooked

[lettucebe]

13. Haha, makes no sense -- if the water is safe, the water is safe, cold or hot

I bake a lot and I always will fill a pot that is to contain boiling water or hot water with hot water straight from the faucet. Some places you are not supposed to drink the water (not sure, our water in Washington State is fine) but still thought boiling the water renders it a-okay.

[Cozmo]

15. Don't think this has anything to do with water safety

I guess we all have differing experiences regarding the love and art of cooking.

[GemDigger]

17. All hot water heaters suggest draining it periodically.

All the minerals and whatever else is in the water over time settles on the bottom like a very dirty fish tank.

[Phentex]

23. our tap water reeks of chlorine!...

I hate it. It's worse when showering. If anything is gonna get me, it's the chlorine.

[BigmanPigman]

14. What I want to know is

why you add salt to boiling water (for stuff like pasta) and not before it boils. Does it take longer to get the water temp back up to a boiling temp?

[Cozmo]

16. Depends on where you live and elevations

Salt is added to pasta for flavor as the cooking process leeches out natural salt in pasta

[Phentex]

22. Boils faster...

is what I've been told.

[Major Nikon]

20. In some countries, notably the UK, hot water often comes from a stored source

A cistern in the attic stores water which is heated before use. Stored water is generally not what you'd want to use for drinking or cooking.

As others have mentioned, hot water leaches heavy metals from old pipes.

So there's at least a couple of reasons why in certain circumstances you wouldn't want to use hot water. In order to take the guess work out of it, many recipes specify cold water use.

[sir pball]

21. Fun fact, that's why UK sinks often have separate spigots

One hot, one cold, so you won't drink from the hot.

Myself, I use my electric kettle to heat cold water to a boil, then use it for cooking. Bit roundabout, but between 25+ years of habit and the theoretical possibility of hot water leaching lead from my 1906 pipes I can't bring myself to use hot water from the tap.