Making icecubes.
May 4, 2010 11:39 PM Subscribe
Should I use warm or cool water when I fill an ice cube tray to freeze?
It has been said that when filling a coffee pot you should use cold water. Now then, does the same chemistry apply when you start an ice cube tray?
Should I use hot water to fill the tray? I want ice cubes as soon as possible to cool my drink.
It has been said that when filling a coffee pot you should use cold water. Now then, does the same chemistry apply when you start an ice cube tray?
Should I use hot water to fill the tray? I want ice cubes as soon as possible to cool my drink.
The reason you use cold water in a coffee pot is because hot/warm water has been passed through the boiler/heating system, increasing the chance that there are impurities in the water. It has nothing to do with the chemistry of the water. If you want ice cubes, you should use cold water.
posted by suedehead at 11:56 PM on May 4, 2010 [1 favorite]
posted by suedehead at 11:56 PM on May 4, 2010 [1 favorite]
You should use cold water in a coffee pot to minimize dissolved minerals in the water, hence reduced scale in the pot.
You should use cold water in your icecube tray, unless very specific conditions are met. You're thinking of the Mpemba effect.
posted by defcom1 at 11:57 PM on May 4, 2010
You should use cold water in your icecube tray, unless very specific conditions are met. You're thinking of the Mpemba effect.
posted by defcom1 at 11:57 PM on May 4, 2010
A better physicist is going to come along soon probably, but I have always heard you use warm water, like from the hot water tap, to make ice that is clear -- the longer it takes for the water to freeze the more air that escapes and the clearer the cubes.
Yeah, I don't think so.
I've found that boiling some water results in very clear ice. All of the other gases are forced out in the boiling process.
But warm water? Just the same as cold water, only it takes longer to freeze.
posted by Netzapper at 11:59 PM on May 4, 2010
Yeah, I don't think so.
I've found that boiling some water results in very clear ice. All of the other gases are forced out in the boiling process.
But warm water? Just the same as cold water, only it takes longer to freeze.
posted by Netzapper at 11:59 PM on May 4, 2010
The EPA are pretty clear on their recommendation: never cook with or consume water from the hot-water tap. It's about the level of dissolved lead in your water.
posted by surenoproblem at 12:13 AM on May 5, 2010 [5 favorites]
posted by surenoproblem at 12:13 AM on May 5, 2010 [5 favorites]
Hot tap water is for cleaning and bathing but never drinking or cooking. Hot water leeches out lead from soldier joints much faster than cold, and the hot water heater is a giant collection bin for sludge, sediment, and bacteria.
posted by Rhomboid at 12:17 AM on May 5, 2010
posted by Rhomboid at 12:17 AM on May 5, 2010
I never heard that. I use hot tap water for ramen and I'm still alive. Hmm, maybe I should have my lead levels checked...
posted by IndigoRain at 12:32 AM on May 5, 2010 [1 favorite]
posted by IndigoRain at 12:32 AM on May 5, 2010 [1 favorite]
After experimenting: hot water --> clear ice, cold water --> cloudy ice. Don't know the chemistry about why. I just stumbled upon it one day. So now I only use hot water to make ice.
posted by wherever, whatever at 12:32 AM on May 5, 2010
posted by wherever, whatever at 12:32 AM on May 5, 2010
> I want ice cubes as soon as possible to cool my drink.
Not as simple a question as it first appears! But despite old wives' tales to the contrary, cold water does freeze faster than hot water in normal circumstances. Here's another source.
posted by churl at 1:05 AM on May 5, 2010 [1 favorite]
Not as simple a question as it first appears! But despite old wives' tales to the contrary, cold water does freeze faster than hot water in normal circumstances. Here's another source.
posted by churl at 1:05 AM on May 5, 2010 [1 favorite]
I just wanted to mention this since it comes up every time: there is the so-called Mpemba effect that allegedly means that hot water freezes faster than cold; but I've been tracking this idea on the internet for some time and no one seems to be able to reproduce these results in average, every-day settings. My vote goes to cold water.
posted by PontifexPrimus at 1:09 AM on May 5, 2010
posted by PontifexPrimus at 1:09 AM on May 5, 2010
Let me add my 2ยข. I happen to be a physicist and not sure if I can say anything more enlightening than has already been said. Water used for cooking or drinking should come from the cold tap. Hot water will likely have slightly more dissolved impurities than cold water, besides it is cheaper to use cold water. I doubt if lead need be worried about in newer plumbing systems; the solder used on copper pipes no longer contains lead. Besides, it is difficult to get significant quantities of dissolved lead, because the most common lead compounds are very insoluble.
Economically speaking, you use less energy in heating cold water than running the hot water until it gets warm and using that warmed water to be heated on the stove.
Regarding clear ice: it has already been noted that boiling water makes clearer ice than cold water. It has been suggested that boiling removes much of the dissolved gas and reduces the trapping of gas bubbles in the ice. I agree. This brings up whether hot water freezes faster than cold water.
This subject will always get an argument in a physics department. For my part, I have empirical evidence that hot-water pipes freeze before cold-water pipes. I have thought this was due to the water in the hot-water pipes (cooled after standing in the pipes) containing less dissolved gas than the water in the cold-water pipes. It is basic thermodynamics that dissolutes increase water's boiling point and decrease water's freezing point.
posted by Hilbert at 2:47 AM on May 5, 2010 [3 favorites]
Economically speaking, you use less energy in heating cold water than running the hot water until it gets warm and using that warmed water to be heated on the stove.
Regarding clear ice: it has already been noted that boiling water makes clearer ice than cold water. It has been suggested that boiling removes much of the dissolved gas and reduces the trapping of gas bubbles in the ice. I agree. This brings up whether hot water freezes faster than cold water.
This subject will always get an argument in a physics department. For my part, I have empirical evidence that hot-water pipes freeze before cold-water pipes. I have thought this was due to the water in the hot-water pipes (cooled after standing in the pipes) containing less dissolved gas than the water in the cold-water pipes. It is basic thermodynamics that dissolutes increase water's boiling point and decrease water's freezing point.
posted by Hilbert at 2:47 AM on May 5, 2010 [3 favorites]
I was just researching this last week, as we discovered upon replacement that our fridge's ice cube maker had been connected to the hot water line all these years. There are a lot of plumbers on the internet who claim to do this on purpose, because it makes for clearer ice cubes. And then there are a lot of other people on the internet who cry foul because the hot water is likely to have more minerals (and potentially lead) dissolved in. The conclusion I came to is that a lot of people use ice made from hot water, but I personally don't want to.
posted by vytae at 4:07 AM on May 5, 2010
posted by vytae at 4:07 AM on May 5, 2010
Here's a guy that did some (fairly non-scientific) testing of freezing (and boiling) hot vs. cold water. His results show that room temperature water freezes much faster than hot or boiling water.
posted by Dojie at 4:49 AM on May 5, 2010
posted by Dojie at 4:49 AM on May 5, 2010
I thought the reason you don't drink from the hot water tap is because of the dissolved metal compounds from the water heater anode.
posted by DarkForest at 5:29 AM on May 5, 2010
posted by DarkForest at 5:29 AM on May 5, 2010
Best answer: If the only thing you care about is the speed at which you get your ice cubes, you should use hot water (see: Mpemba Effect). If you give a shit about the quality of your ice, you should only use cold water, and only after you have run the water long enough to make sure it's not coming from your building (i.e., purge all standing water from the system). Your ice will have less sediment, which is clearly visible as a foggy part in the center of the ice cube (well, visible if you have it).
Either that, or just use filtered water (which you can use warm, by the way… get the best of both worlds). When you buy ice from a store, you'll notice that all the cubes are completely transparent: that's because they use filtered water. If you used filtered water, you'd get clear ice as well.
posted by Civil_Disobedient at 5:56 AM on May 5, 2010
Either that, or just use filtered water (which you can use warm, by the way… get the best of both worlds). When you buy ice from a store, you'll notice that all the cubes are completely transparent: that's because they use filtered water. If you used filtered water, you'd get clear ice as well.
posted by Civil_Disobedient at 5:56 AM on May 5, 2010
The Mpemba Effect isn't very strong, and it's a difficult experiment to reproduce. Read the wiki article, particularly the 'Causes' section, and note that there are many variables at work, some of which oppose each other - it's not a single variable (hot vs cold) experiment at all, and an attempt to perform the experiment without taking these other effects into consideration yields essentially meaningless results that are all over the place... which is why even physicists argue over the problem, because different sets of assumptions and conditions can tip the experiment in different directions.
(When our physics lab groups performed the test, the people who got their samples into the freezer early got very different results from those that came after, because the opening and closing of the door and the condensation from earlier samples changed the physical environment. You can think of it this way: hot water will have to pass through the same temperature as the 'cold' water started at on its way toward freezing, but the hot water will have changed the immediate local environment such that it doesn't experience the same conditions at that temperature that the cold water did.)
As I see it there is some danger in telling people that their belief that 'hot water freezes faster' is 'proven' by the Mpemba Effect. It's not like they've got a scientific fact in their heads they didn't know the name of... they've got faulty folk-science in their heads, and giving them a fancy-sounding scientific name to back it up just makes the problem worse.
posted by foobario at 6:44 AM on May 5, 2010 [1 favorite]
(When our physics lab groups performed the test, the people who got their samples into the freezer early got very different results from those that came after, because the opening and closing of the door and the condensation from earlier samples changed the physical environment. You can think of it this way: hot water will have to pass through the same temperature as the 'cold' water started at on its way toward freezing, but the hot water will have changed the immediate local environment such that it doesn't experience the same conditions at that temperature that the cold water did.)
As I see it there is some danger in telling people that their belief that 'hot water freezes faster' is 'proven' by the Mpemba Effect. It's not like they've got a scientific fact in their heads they didn't know the name of... they've got faulty folk-science in their heads, and giving them a fancy-sounding scientific name to back it up just makes the problem worse.
posted by foobario at 6:44 AM on May 5, 2010 [1 favorite]
> If the only thing you care about is the speed at which you get your ice cubes, you should use hot water (see: Mpemba Effect).
Civil_Disobedient: the Mpemba Effect is an anomalous behavior where in very specific and unusual circumstances warmer water can freeze faster than colder water. It is not the norm.
posted by jehsom at 7:02 AM on May 5, 2010
Civil_Disobedient: the Mpemba Effect is an anomalous behavior where in very specific and unusual circumstances warmer water can freeze faster than colder water. It is not the norm.
posted by jehsom at 7:02 AM on May 5, 2010
My understanding of why you ought use cold water fresh from the tap when boiling water for coffee or tea is because the fresh water has more dissolved oxygen, which makes the drink more flavorful by binding more of the flavor molecules you want. If you re-heat pre-heated water, your drink will taste flat.
(For that matter, though, for coffee and most teas, you want to take the kettle off the stove before the water has actually started to boil. You want it very very hot, but fairly shy of 212'.)
(Also, the lead thing is true.)
(Also, if you're camping or otherwise boiling water to sterilize it, you can remove the flat taste by pouring it back and forth between two containers a few times.)
posted by J-Train at 8:52 AM on May 5, 2010
(For that matter, though, for coffee and most teas, you want to take the kettle off the stove before the water has actually started to boil. You want it very very hot, but fairly shy of 212'.)
(Also, the lead thing is true.)
(Also, if you're camping or otherwise boiling water to sterilize it, you can remove the flat taste by pouring it back and forth between two containers a few times.)
posted by J-Train at 8:52 AM on May 5, 2010
If you want ice cubes as soon as possible to cool your drink, then take 2-3 ice cube trays and put about 1/4" depth of cold water in each little cubby (large surface are to volume ratio). Put in the freezer, preferably a freezer that already contains lots of frozen stuff (large thermal mass to maintain coldness) but spread the trays out, don't stack them together (better circulation of the cold air). Of course, this will make you three trays worth of little thin ice bits, and it might take all of it to fill one large glass with your ice. But you just want to cool your drink, right?
posted by aimedwander at 10:21 AM on May 5, 2010
posted by aimedwander at 10:21 AM on May 5, 2010
For my part, I have empirical evidence that hot-water pipes freeze before cold-water pipes.
Freeze, or burst?
posted by gjc at 4:16 PM on May 5, 2010
Freeze, or burst?
posted by gjc at 4:16 PM on May 5, 2010
The Straight Dope: Which freezes faster, hot water or cold water?
Interestingly, I was always told growing up not to use warm/hot water when filling the ice cube trays because they could crack the plastic trays when they froze. Apparently that was hogwash.
posted by sprocket87 at 12:21 PM on May 6, 2010
Interestingly, I was always told growing up not to use warm/hot water when filling the ice cube trays because they could crack the plastic trays when they froze. Apparently that was hogwash.
posted by sprocket87 at 12:21 PM on May 6, 2010
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Of course that also means you are heating up your freezer in the first couple of minutes after the cube are put in (well, you always are, but in this case for longer), and if you don't care about white-cloudy ice (I don't), then using cold or cool water makes more sense.
posted by Some1 at 11:55 PM on May 4, 2010