DarkRange55
Enlightened
- Oct 15, 2023
- 1,256
An old myth is that cocktails require 'extra-cold ice'. Supposedly an ice company was promoting its ice as being the best ice for cocktails. If snow is the same temperature as the air outside, can't you achieve "extra-cold ice," it just depends on the environment like icebergs in the arctic? Or no, thats just a misnomer? A lot of the ice questions come from a salesmen/co-founder for a high-end ice company who was making some claims in an interview online.
There are +17 different types of ice but at a given temperature, what you call "ice" has a fixed density like water. The gentlemen's claim is that because they freeze their purified water as a block with a large volume, their ice is somehow more "molecularly dense." That's a totally absurd notion, because ice (as a continuous lattice, not shaved ice) undergoes a phase change from a (nearly) incompressible fluid (water)— ideal gas law and phase change mechanics (laws of hydraulics) - Ice can definitely become more dense with pressure, but it takes a lot of pressure to make much difference at all. Extra cold ice would be ice that was stored in a cold freezer. At -40°C, it would cool 50% more than ice at 0°C, and thus dilute the drink less (in the initial chilling would be almost dilution-free). The temperature, or the pressure that the ice is frozen at would make no difference at all, nor would the size of the block of ice. Yes, you could theoretically have a slab of ice large enough to last throughout the whole summer – it is called a glacier. Adding a bit of insulation, and the masses more manageable – before refrigeration, ice was kept in ice houses all summer and shipped around the world, all using sawdust as insulation. The difference in density of ice is almost entirely due to the presence of air bubbles. Air bubbles affect the thermal conductivity of ice more than the density. Freeze and thaw the water a few times, and the air bubbles will be gone the next time it is frozen. Larger ice cubes will melt more slowly, diluting a drink less, but they also cool the drink less quickly.
Hand carved ice?
I cannot think of any measurable value in hand carved ice cubes.
Spherical ice vs traditional ice cubes?
Kilogram per kilogram, a spherical ice cube will melt slower, but also will cool slower. But traditional ice cubes are not that far from spheres, so the effect is pretty minor.
I recently read that, in a cocktail you can shake it to a certain point and that's as cold as it's going to get, under normal conditions, most cocktails will not get any colder than –7°C?
The limit of -7°C is probably due to the alcoholic content of the resulting drink. It takes an awful lot of shaking to heat up a cold liquid…
On planets outside of the inner solar system like Titan and Pluto some of the hardest rocks in the crust of those worlds are made of water ice (ice is a mineral & water a mineraloid) .
The Bank of America tower uses an ice A/C - Price of electricity changes every hour so the Bank of America building in downtown Bellevue makes ice when electric prices are low and then uses that ice (the size of a walk in freezer) to cool their building.
So why can't we use salt brines or ethanol solutions as heat transfer fluids? The short answer is that you can and in some instances we do, but for many applications they present more problems than they solve. Salt brines are often very corrosive causing the need for more robust materials of construction and ethanol is flammable causing explosion proof construction of the chiller unit.
Thermoelectric cooling
Water expands when heated
Salt water cools engines on boats oftentimes
Swamp coolers vs A/C - see index
Pre-chilling a cooler or freezer will make it so the cooler or freezer walls don't pass their heat into your food warming it up. Pre-chilling a cooler will make the ice last way longer. Way better than air, so the the warm cooler walls will melt your ice and food. If you cool your cooler with a small amount of ice, then dump it before putting in all your food and ice for the trip and replace it. Then the ice doesn't have to do all the work to get the cooler down from room temp. Which melts a ton of ice and gets rid of a lot of your cooling potential. (This applies to glasses, too).
Air circulation - cools things better by making sure the air that warms up from food cooling down is removed and replaced with cold air and that warm air can go cool down again. Air circulation would also aid in the evaporation effect (see evaporate cooling). Air is a great insulator (think bubble wrap in the freezer, doesn't make it colder, it just insulates). An empty freezer is the fastest way to reach the freezer's coldest temp, but having copper blocks loosely in baskets will provide stored cold to cool faster initially. Empty freezer for freezing things = most air flow. You do get extra cooling from items that are already frozen but I'm not sure that's a good thing. You don't want items to melt and refreeze which most likely happens when a warm item is set on a frozen item. Full would be good in the event of a power outage since all the food is pretty much ice. Most frozen food should be similar to water but will be slightly different (most foods have a high water content). Although, "food is bad conductor of heat," isn't so simple. If you look further into the referenced study, it cites having a large valine to surface area being one of the big factors. Most everything else in your freezer is likely to be a much better thermal conductor (than ice) and is thus able to absorb the heat from the newly placed item much faster than air alone. For conduction, yes, almost any food will conduct better than air. But if you place food loosely in a tray it will freeze pretty fast due to convection, and you can then transfer to glass jars or plastic bags. In contrast, it is hard to get good thermal contact to other foods so you almost always end up with an air gap that ruins the intended conduction.
Water is a decent heat conductor, that's why it's used as a cheap coolant. However there's a ton of better coolants (depending on what temp range...) Water is not an insulator because it does transfer heat well (highest conductivity I know for for a nonmetallic liquid). Water is not an insulator of heat in the sense that word is used for ceramics, refractory bricks, glass wool, rock wool or thermocole. Water has a large thermal capacity because it has the highest specific heat. So, water absorbs a large amount of heat before its temperature raises significantly. I think when you say a good insulator, you mean it can keep temperatures steady. Water has a pretty large heat capacity, which is how much energy it takes to heat it up, and naturally the amount of energy it will release as it cools down. Because its heat capacity is so large it can prevent things from heating up or cooling down too quickly, but only if the water is at that same temperature. Its not actually "insulating", which is how quickly heat moves between something hot and something cold, instead its holding a lot of heat. Water is used as a coolant a lot because its a liquid so that can make good contact on something you want to cool, and you can pump it easily bringing new water in contact with the thing you want to cool. As well as the fact that it can hold a lot of heat given off by the thing you want to cool. Water and steam are in fact used as heat transfer medium. In some cases its also used for evaporative cooling, that is it cools things down by absorbing heat in order to go from liquid to a vapor because there naturally wants to be a certain amount of water vapor in the air and if the air is dryer than that it will pull in liquid water. However for evaporative cooling there are a lot of other refrigerants people use in things like air conditioning systems and refrigerators by pumping it and letting it expand. Water isn't really an exceptional coolant, its pretty good and its cheap. And its not really an insulator, its just a big stockpile of temperature that you have to drag along with stuff around it when heating or cooling. It depends on if the water is moving or not. There are three modes of heat transfer: conduction, convection, and radiation. Radiation is irrelevant in this example. Conduction is heat transfer through the collision of molecules. Hot molecules collide with colder molecules and transfer energy. The speed at which a material transfers heat through conduction is described by its thermal conductivity, which is a basic property of the material. Water's thermal conductivity is about 0.6 W/(m*K). For reference, most metals have thermal conductivities of around 300 W/(m*K). Many plastics, silicons, epoxies, etc. are ~0.15, of 4x worse than water. Air is ~300X worse. Aluminum is considered a very good conductor at ~200 W/mK. Steels are 25-50... Water is a good conductor for a liquid (about the same as glass). Ice is ~2x better than water. Steam is a poor conductor, but condensation transfers heat really well. Water is used as a coolant (i.e. water cooled PC's, nuclear cooling towers, radiators, ect) but it takes a lot of energy to heat up water. Its not as efficient as copper but its a better conductor than some insulators (better than alcohol). Convection is heat transferred by a moving fluid. It is much much faster than conduction because it is a combination of both conduction and something called advection. You can think of advection as basically the hot molecules moving somewhere else and mixing with cold molecules.
So instead slowly transferring heat to different locations by colliding with other molecules, convection just moves those hot molecules to different locations. In addition to convection being faster than just conduction, water also has high specific heat, which means its temperature does not change quickly when heat is added. Heat transfer is faster if there is a large temperature difference between the hot and cold material. Since water is able to maintain is temperature longer even when absorbing heat, it is a rather effective coolant. Water has the highest specific heat capacity for any liquid. Specific heat capacity is defined as the amount of energy it takes to raise 1 ml of a substance by 1 degree Celsius. Since water is high, it take a large amount of energy to raise its temperature. It's not a good insulator, but if water is heated up it can be. Wet suits operate under this principle. Air is a poor conductor of heat but a great insulator, which is why we use it as an insulator inside double-glazed windows. Argon is actually even better than air and is used sometimes but its more expensive. Old houses were water heated and even older houses were steam heated. Water and steam were used to transfer heat instead of heating the air. Most things now just have forced air. Wearing a down coat in the winter, its the air keeping you warm. Get the clothes wet and its not a good insulator and you're in trouble. The water is conducting heat away from the body - transferring heat from one medium to another (dumping heat from the body to the air). Sweat conducts heat away from the body. In both cases its both conduction and phase change (evaporative cooling).
According to physics, block ice is more efficient for long term cooling. Large single pieces of ice have a reduced surface area compared to their volume. Due to the energy required in the phase-change, this lowers the maximum rate of melting (and also the maximum rate of cooling). The volume of an ice cube goes up as the third power of its size, but the surface area goes up as the square of the size. Small ice cubes, therefore, have a larger surface area per gram than large ice cubes. Since water resides at the surface of wet ice, immense amounts of surface area will unfairly add to dilution. So you could keep slabs of ice frozen year 'round outside if they are big enough and larger ice cubes will melt slower this less dilution in the drink.
This is due to the fact that large ice cubes have a large volume compared to surface area so they stay cold longer. Small ice cubes have high surface area to volume exposed to the surrounding heat as compared to its relative density. While ice cubes melt faster than block ice, they do a great job of filling in the cracks. Larger ice cubes will melt more slowly, diluting a drink less, but they also cool the drink less quickly. If you isolate the system (put the drink and the ice together in a thermos), then the overall cooling will not depend on the shape of (but on the volume and the temperature of) the ice. However, if the system is not isolated, then the slower melting of the spherical ice allows more time for heat to leak in from the outside world, so the coldest temperature reached is not quite as cold. The temperature of the contents goes to the freezer temp.
Snow is just as cold as ice, but the air it contains makes it a good insulator, and thus not as good at sucking out heat (unless air/fluid moves through it). Ice beats gel for heat absorption. Ice is hard to beat for amount of cold. Freezer packs could be made to be colder, but then might frost the food. Clear ice isn't inherently colder than cloudy ice but it melts slightly slower - more ice, less air... igloos are not made of ice, you'd freeze! The blocks are packed snow, ~1/4 the density of ice. Also, in cold weather it is the freshly-cut edges (broken snow crystals) that are most responsible for sticking the blocks together. Not to be confused with the melting of ice which can hold it together. When ice blocks are placed on top of each other the weight/pressure of the block causes the ice to slightly melt. This is called regelation. The water layer now refreezes thereby cementing the ice blocks together. The heat capacity of water is substantially higher than the heat capacity of air. The heat given off by people inside igloos can substantially warm the air inside (helped out by the fact that snow is a great insulator). But because the snow/ice/water that makes up the igloo structure has so much more mass and has such a higher heat capacity than the air inside, the igloo melts slowly. Snow has only 1/10 of the mass of an equivalent volume of water. It also has a lot of trapped air (90-95% of its composition). But for it to conduct heat effectively, it has to undergo a phase change. It takes a lot of energy to melt snow. If the walls are too thick, the inside of the walls will not be able to give away any heat they absorb from the people and lamps inside the igloo so the inside of the walls will melt a bit until the walls thin out enough that it reaches an equilibrium point, where the warmth absorbed from inside is exactly lost to the outside through the walls and no further melting occurs. Electrical resistance or thermal resistance: Snow consists of ice crystals and air. It turns out that water is a actually a poor electrical conductor, and frozen water (ice) is an even poorer electrical conductor.
Since air is also a very poor electrical conductor, it shouldn't be surprising that the combination is a very poor electrical conductor... and thus a good insulator. In cold climates snow is often found covering the high-voltage insulators in electrical power systems with no arcing or flashovers since it behaves as an insulator. Snow is also a great thermal insulator due to the presence of entrapped air spaces in the snow matrix. And the snowflake crystals prevent convection cells forming. Animals build "caves" inside snow banks to help keep warm. The snow near the ground is much warmer because it is more near to the low layer of ground and this is the best place for the animals to hide in winter. This snow acts as the best natural insulator.
Salt melts ice down to ~0F. The salt plus ice helps cool at first, but then impedes at ~0F (as slush refreezes); the rest just gets in the way of the cooling.
The effectiveness of the evaporative cooling effect of a wet paper towel around a can in the freezer, speeds cooling at first, then cooling slow as towel freezes or dries outer.
Water freezes into very pure ice, forcing almost all the dissolved substances out. This works for concentrating maple sap and ethanol as well as for salt. Yes, brine can drain out of ice over time.
Ice on top provides more-even cold
What makes "fresh ice" better?
Marketing?
Glacial ice fans disagree.
Water molecules migrate and stick at just below 0C. And external temp swings can melt and refreeze ice that is stored just around 0°C/32°F
- Is clear ice inherently colder than cloudy ice?
No.
In regards to microbes surviving in ice in Antartica, "the organisms survive in various ways, mostly by taking advantage of minuscule cracks in the ice containing flowing water." Is this the same thing as the ice having a pre-melted layer of water on it? Whats causing it to flow? Salt keeps the water in the crack liquid?
Metal and ice can get equally cold. They get as cold as the freezer they're in. Ice has a greater heat capacity than most metals, meaning it stays cold for longer, and there is a large latent heat when it melts, which means it absorbs a lot of heat from the ambient water without changing its own temperature as it melts. This allows it to cool down water by warming and melting more than the same size cube of metal could. To put a number on things, the specific heat capacity of water is about eight times larger than that of stainless steel. And that's leaving aside its very high latent heat of fusion.
Metal's higher density would largely offset its lower specific heat capacity for cubes of equivalent volume. Water still has the edge over metals even on a per volume basis, but it's not the factor of 8 that one gets on a per mass basis. For cubes of the same volume, the factor is more like 1.2 or 1.3 depending on the metal. The latent heat contribution from melting ice, on the other hand, would be roughly triple that from the heat exchanged in warming the ice to its melting
point and then to room temperature, with no
counterpart from the metal cubes. Therefore, I think that latent heat is the real issue to dwell on. But the catch with latent heat is that it, by definition, is absorbed when the ice melts. And when very much ice melts, it makes the drink taste flat. Hence the whiskey stones mentioned by others, made possible (though perhaps not convenient) by the higher density of metals as noted above.
The density of the metal cubes has another
aspect: steel weighs about 8 grams per cubic cm, and water 1 gram (8kg and 1kg per liter). Meaning that a mojito and some other ice applications could be unwieldy. Also, hot water rises. Due to its low density, ice also rises, meaning that the hottest water is always in contact with ice. Metal would settle at the bottom, potentially not cooling the top of a tall glass as well. But actually the highest density of water is at 4°C, so the ice could be in contact with the coldest water.
Other substances that expand on freezing are
silicon, gallium, germanium, antimony,
bismuth, plutonium and also chemical
compounds that form spacious crystal
lattices with tetrahedral coordination. But do they also expand before freezing?
It's a huge effect for the ice to be on top. Ice
cubes on the bottom of a glass melt about 3x
slower. So 3-5x slower cooling, which means
roughly 3-5x smaller temperature drop. Melting 3-5x slower essentially means 3-5x slower cooling, which means roughly 3-5x less temperature drop. The large majority of the energy ice absorbs is through the melting process, while the temperature change makes a very small difference. Melting isn't a byproduct of the ice warming. The melting itself is the mechanism that cools your drink. The ice
warming is just a side process until you reach the melting point that cools a small amount. Then it remains at a constant temp while it cools your drink through heat of fusion.
I would say significant (ice on top). One aspect of why ice does a good job of cooling water is that the water at the top of the column that gets cooled by the ice, falls to the bottom, creating a
convection current that constantly brings
warmer water to the top to be cooled, keeping a
fairly uniform temperature in your glass. With
the cooling source at the bottom of the glass,
you'd get a temperature gradient, driven by the
ability of the water to conduct heat. Convection
transports heat better than conduction, so the
effect could be noticeable. To add to this, with metal cube drink's temperature would rise gradually. Where with ice melting, the drink's temperature would gradually falls and stay there while the cube melts.
It is quite literally the process of melting ice that absorbs heat from the drink. No melting, you'd get comparatively almost no cooling from the ice. The ice increasing in temperature does nearly nothing to the temperature of a drink. It's basic science that the heat of fusion is what does most of the cooling when you put ice in a drink. Not sure what you're on about. The process of melting itself takes most of the energy from your drink and cools it. The same principle is used for most physical (not using electricity) cooling applications. Gel packs, liquid nitrogen, etc. They are effective
because of phase change. Your "ice absorbs the heat and then melts" is actually talking about the phase change itself, which is melting.
You can cool without a phase change, but you get relatively little cooling, this is THE reason why ice cubes are still more precelant than metal cubes for cooling drinks. Refrigeration systems are the most popular method of cooling, and they are completely based around the phase change of the refrigerant within the system. The refrigerant is changing from a gas, to a liquid, back to a gas within the system. You would have nowhere near the same cooling capacity if it only pumped a liquid through the system without any phase changes.
Diffusion says water in contact with
the ice will drop to and stay at 0 C because any additional heat transferred to the water will go toward melting the ice. The 100% surface contact with the liquid makes this even easier. Heat isn't going to diffuse out of the liquid into the environment, because the environment is warmer. With enough contact and bulk, the inside of the system isn't going to increase in temperature until all the heat of fusion is absorbed first. Phase changes eat a lot of energy.
You drop cube of ice into water, the water that's already there won't be at 0 C, but all the water that used to be ice would start at 0 C and quickly warm up. Ice cube will never be above 0 C, it will change states into water before it warms up above 0 C. Practically, no one is trying to cool their coffee with ice. You have a cup that's half or more ice, you poor 20C water in it. Water fairly quickly drops close to 0 C and all the water that used to be ice will start out at 0 C, keeping the drink "cold". As ice melts (like said, change of state takes a lot more energy than just transfer of heat from one part of liquid to another) and continuously adding 0 C water to your drink it will stay very close to 0 C until a large portion of the ice is gone. The latent heat contribution from melting ice, on the other hand, would be roughly triple that from the heat exchanged in warming the ice to its melting point and then to room temperature, with no counterpart from the metal cubes. Therefore, I think that latent heat is the real issue to dwell on.
Metals also have a latent heat of fusion....
The part about ice not going above 0C is correct...
At the density of water, we gain roughly one atmosphere pressure for every 10 m, or 100 atm per kilometer, so an 11 km deep trench would have over 1000 atm pressure.
But an interesting fact about water is that it probably has the highest density at around 4 degrees celsius. This might enable it to give you a different "feel" if you keep it on your tongue? Most fridge or chillers would chill water up to around this temperature.
Heavier atoms tend to produce denser solids, but bond length is also critical. Molecular weight has very little to do with density, buoyancy is simply the difference in density between something and what is immersed in, times the volume of the something.
Most glacial ice is at least as clear as most ice cubes. But it usually comes in much bigger pieces that show off its intrinsic color better than a small piece would. Glacial ice starts out as fairly porous snow, but by the time it becomes deep glacial ice, the air bubbles are greatly compacted, but it is still not as dense as ice made from boiled water or several-times-refrozen water.
Yes, water freezes into very pure ice, forcing almost all the dissolved substances out. This works for concentrating maple sap and ethanol as well as for salt. Yes, brine can drain out of ice over time. This works for concentrating maple sap and ethanol as well as for salt. Yes, brine can drain out of ice over time.
Unless ice cubes are individually wrapped, sticking together is about whether they've been allowed to partially thaw and refreeze, not whether they are "premium?"
Ice will also freeze to itself (basically a diffusion bond) over time, especially with a bit of pressure. I would not expect premium ice to be any different in this regard.
With cocktails presentation is one of the most important things. If you are taking the time to make sure everything else is perfect might as well make sure the ice is also perfect.
Snobby cocktail bar with obscure ingredients and lots of theater? Gotta include fancy ice. Local pub? Who cares? Somewhere in between? Just can't taste bad and needs to be dense enough to do it's job
I think it would be somewhat important if your goin got a cocktail bar sort of thing where the cocktails are the centerpiece of what your serving. But if your just a normal restaurant serving cocktails I wouldn't be too worried about it. How expensive is the cocktail?
directional freezing. In essence; you inhibit freezing on all sides but one in order for the trapped gasses that are usually trapped in the ice to escape from one direction. meaning you get an ice clearer than one frozen from all directions at once.
the big clear ice cubes that you see in bars don't come from ice machines as you know them; most will have come from a giant block of ice produced in a large and very expensive Clinebell machine, which takes a few days to generate and then needs to be broken down into manageable chunks. For a lot of bars this is too much work, so they outsource to companies that can provide pre-cut cubes, collins spears, and so on. If you want to achieve the same results at home, you'll need to either use a Wintersmiths product or similar, or set up an insulated cooler in your freezer and break down the resulting block.
Saturated (dry) steam results when water is heated to the boiling point (sensible heating) and then vaporized with additional heat (latent heating). If this steam is then further heated above the saturation point, it becomes superheated steam (sensible heating).
en.m.wikipedia.org
Water is adhesive and the weight of the water pulls the other water. The air breaks that.
Most toilets utilize a siphon to empty the water when the level rises quickly enough to create a seal in the top of the "U"-bend. The siphon process then carries the water down the pipe until air enters and the siphon is broken.
Ice is a mineral. It freezes in the hexagonal crystal system. Think about it like snowflakes. They are frozen six sided hexagonal crystals composed of frozen water. Another interesting fact is that frozen water like in a lake is natural ice where as frozen ice cubes from your refrigerator are considered synthetic ice.
One of the weirdest aspects of water is its unusual density. Normally, liquids become increasingly dense as they are cooled down, but water reaches a maximum density at about 4 degrees Celsius (39.2 Fahrenheit).
Below this point it is less dense, so when it freezes and becomes ice at 0 degrees Celsius (32 Fahrenheit), the ice is less dense than the water. This is why water ice floats, and bodies of water freeze from the top down.
But that's not all. Water also has really high surface tension - aside from mercury (https://www.sciencealert.com/mercury), it has the highest surface tension of all liquids. This is what allows water spiders to skate across the top.
To top it all off, water also has an unusually high boiling point, and the fact that so many chemical substances dissolve in it is also really peculiar, if we compare it to other liquids.
At room temperature and as ice, water has a tetrahedral arrangement (https://phys.org/news/2013-02-scientists-tetrahedral-molecular.html)
of molecules, which means every water molecule is bonded to four others in a rough pyramid shape.
Iceberg ice (and other glacial ice) that is more than a few thousand years old is generally free from modern pollutants, but other than that it is mostly a marketing gimmick.
Most minerals in mineral water are pretty stable, having already had many years in which they could react if they wanted to. However, the plastic bottle can indeed deteriorate, especially if exposed to heat or sunlight. If you leave a bottle of water in the car on a hot day, even if you let it cool afterward it will taste plasticky, mineral water in a glass bottle should not have an expiration date.
There are +17 different types of ice but at a given temperature, what you call "ice" has a fixed density like water. The gentlemen's claim is that because they freeze their purified water as a block with a large volume, their ice is somehow more "molecularly dense." That's a totally absurd notion, because ice (as a continuous lattice, not shaved ice) undergoes a phase change from a (nearly) incompressible fluid (water)— ideal gas law and phase change mechanics (laws of hydraulics) - Ice can definitely become more dense with pressure, but it takes a lot of pressure to make much difference at all. Extra cold ice would be ice that was stored in a cold freezer. At -40°C, it would cool 50% more than ice at 0°C, and thus dilute the drink less (in the initial chilling would be almost dilution-free). The temperature, or the pressure that the ice is frozen at would make no difference at all, nor would the size of the block of ice. Yes, you could theoretically have a slab of ice large enough to last throughout the whole summer – it is called a glacier. Adding a bit of insulation, and the masses more manageable – before refrigeration, ice was kept in ice houses all summer and shipped around the world, all using sawdust as insulation. The difference in density of ice is almost entirely due to the presence of air bubbles. Air bubbles affect the thermal conductivity of ice more than the density. Freeze and thaw the water a few times, and the air bubbles will be gone the next time it is frozen. Larger ice cubes will melt more slowly, diluting a drink less, but they also cool the drink less quickly.
Hand carved ice?
I cannot think of any measurable value in hand carved ice cubes.
Spherical ice vs traditional ice cubes?
Kilogram per kilogram, a spherical ice cube will melt slower, but also will cool slower. But traditional ice cubes are not that far from spheres, so the effect is pretty minor.
I recently read that, in a cocktail you can shake it to a certain point and that's as cold as it's going to get, under normal conditions, most cocktails will not get any colder than –7°C?
The limit of -7°C is probably due to the alcoholic content of the resulting drink. It takes an awful lot of shaking to heat up a cold liquid…
On planets outside of the inner solar system like Titan and Pluto some of the hardest rocks in the crust of those worlds are made of water ice (ice is a mineral & water a mineraloid) .
The Bank of America tower uses an ice A/C - Price of electricity changes every hour so the Bank of America building in downtown Bellevue makes ice when electric prices are low and then uses that ice (the size of a walk in freezer) to cool their building.
So why can't we use salt brines or ethanol solutions as heat transfer fluids? The short answer is that you can and in some instances we do, but for many applications they present more problems than they solve. Salt brines are often very corrosive causing the need for more robust materials of construction and ethanol is flammable causing explosion proof construction of the chiller unit.
Thermoelectric cooling
Water expands when heated
Salt water cools engines on boats oftentimes
Swamp coolers vs A/C - see index
Pre-chilling a cooler or freezer will make it so the cooler or freezer walls don't pass their heat into your food warming it up. Pre-chilling a cooler will make the ice last way longer. Way better than air, so the the warm cooler walls will melt your ice and food. If you cool your cooler with a small amount of ice, then dump it before putting in all your food and ice for the trip and replace it. Then the ice doesn't have to do all the work to get the cooler down from room temp. Which melts a ton of ice and gets rid of a lot of your cooling potential. (This applies to glasses, too).
Air circulation - cools things better by making sure the air that warms up from food cooling down is removed and replaced with cold air and that warm air can go cool down again. Air circulation would also aid in the evaporation effect (see evaporate cooling). Air is a great insulator (think bubble wrap in the freezer, doesn't make it colder, it just insulates). An empty freezer is the fastest way to reach the freezer's coldest temp, but having copper blocks loosely in baskets will provide stored cold to cool faster initially. Empty freezer for freezing things = most air flow. You do get extra cooling from items that are already frozen but I'm not sure that's a good thing. You don't want items to melt and refreeze which most likely happens when a warm item is set on a frozen item. Full would be good in the event of a power outage since all the food is pretty much ice. Most frozen food should be similar to water but will be slightly different (most foods have a high water content). Although, "food is bad conductor of heat," isn't so simple. If you look further into the referenced study, it cites having a large valine to surface area being one of the big factors. Most everything else in your freezer is likely to be a much better thermal conductor (than ice) and is thus able to absorb the heat from the newly placed item much faster than air alone. For conduction, yes, almost any food will conduct better than air. But if you place food loosely in a tray it will freeze pretty fast due to convection, and you can then transfer to glass jars or plastic bags. In contrast, it is hard to get good thermal contact to other foods so you almost always end up with an air gap that ruins the intended conduction.
Water is a decent heat conductor, that's why it's used as a cheap coolant. However there's a ton of better coolants (depending on what temp range...) Water is not an insulator because it does transfer heat well (highest conductivity I know for for a nonmetallic liquid). Water is not an insulator of heat in the sense that word is used for ceramics, refractory bricks, glass wool, rock wool or thermocole. Water has a large thermal capacity because it has the highest specific heat. So, water absorbs a large amount of heat before its temperature raises significantly. I think when you say a good insulator, you mean it can keep temperatures steady. Water has a pretty large heat capacity, which is how much energy it takes to heat it up, and naturally the amount of energy it will release as it cools down. Because its heat capacity is so large it can prevent things from heating up or cooling down too quickly, but only if the water is at that same temperature. Its not actually "insulating", which is how quickly heat moves between something hot and something cold, instead its holding a lot of heat. Water is used as a coolant a lot because its a liquid so that can make good contact on something you want to cool, and you can pump it easily bringing new water in contact with the thing you want to cool. As well as the fact that it can hold a lot of heat given off by the thing you want to cool. Water and steam are in fact used as heat transfer medium. In some cases its also used for evaporative cooling, that is it cools things down by absorbing heat in order to go from liquid to a vapor because there naturally wants to be a certain amount of water vapor in the air and if the air is dryer than that it will pull in liquid water. However for evaporative cooling there are a lot of other refrigerants people use in things like air conditioning systems and refrigerators by pumping it and letting it expand. Water isn't really an exceptional coolant, its pretty good and its cheap. And its not really an insulator, its just a big stockpile of temperature that you have to drag along with stuff around it when heating or cooling. It depends on if the water is moving or not. There are three modes of heat transfer: conduction, convection, and radiation. Radiation is irrelevant in this example. Conduction is heat transfer through the collision of molecules. Hot molecules collide with colder molecules and transfer energy. The speed at which a material transfers heat through conduction is described by its thermal conductivity, which is a basic property of the material. Water's thermal conductivity is about 0.6 W/(m*K). For reference, most metals have thermal conductivities of around 300 W/(m*K). Many plastics, silicons, epoxies, etc. are ~0.15, of 4x worse than water. Air is ~300X worse. Aluminum is considered a very good conductor at ~200 W/mK. Steels are 25-50... Water is a good conductor for a liquid (about the same as glass). Ice is ~2x better than water. Steam is a poor conductor, but condensation transfers heat really well. Water is used as a coolant (i.e. water cooled PC's, nuclear cooling towers, radiators, ect) but it takes a lot of energy to heat up water. Its not as efficient as copper but its a better conductor than some insulators (better than alcohol). Convection is heat transferred by a moving fluid. It is much much faster than conduction because it is a combination of both conduction and something called advection. You can think of advection as basically the hot molecules moving somewhere else and mixing with cold molecules.
So instead slowly transferring heat to different locations by colliding with other molecules, convection just moves those hot molecules to different locations. In addition to convection being faster than just conduction, water also has high specific heat, which means its temperature does not change quickly when heat is added. Heat transfer is faster if there is a large temperature difference between the hot and cold material. Since water is able to maintain is temperature longer even when absorbing heat, it is a rather effective coolant. Water has the highest specific heat capacity for any liquid. Specific heat capacity is defined as the amount of energy it takes to raise 1 ml of a substance by 1 degree Celsius. Since water is high, it take a large amount of energy to raise its temperature. It's not a good insulator, but if water is heated up it can be. Wet suits operate under this principle. Air is a poor conductor of heat but a great insulator, which is why we use it as an insulator inside double-glazed windows. Argon is actually even better than air and is used sometimes but its more expensive. Old houses were water heated and even older houses were steam heated. Water and steam were used to transfer heat instead of heating the air. Most things now just have forced air. Wearing a down coat in the winter, its the air keeping you warm. Get the clothes wet and its not a good insulator and you're in trouble. The water is conducting heat away from the body - transferring heat from one medium to another (dumping heat from the body to the air). Sweat conducts heat away from the body. In both cases its both conduction and phase change (evaporative cooling).
According to physics, block ice is more efficient for long term cooling. Large single pieces of ice have a reduced surface area compared to their volume. Due to the energy required in the phase-change, this lowers the maximum rate of melting (and also the maximum rate of cooling). The volume of an ice cube goes up as the third power of its size, but the surface area goes up as the square of the size. Small ice cubes, therefore, have a larger surface area per gram than large ice cubes. Since water resides at the surface of wet ice, immense amounts of surface area will unfairly add to dilution. So you could keep slabs of ice frozen year 'round outside if they are big enough and larger ice cubes will melt slower this less dilution in the drink.
This is due to the fact that large ice cubes have a large volume compared to surface area so they stay cold longer. Small ice cubes have high surface area to volume exposed to the surrounding heat as compared to its relative density. While ice cubes melt faster than block ice, they do a great job of filling in the cracks. Larger ice cubes will melt more slowly, diluting a drink less, but they also cool the drink less quickly. If you isolate the system (put the drink and the ice together in a thermos), then the overall cooling will not depend on the shape of (but on the volume and the temperature of) the ice. However, if the system is not isolated, then the slower melting of the spherical ice allows more time for heat to leak in from the outside world, so the coldest temperature reached is not quite as cold. The temperature of the contents goes to the freezer temp.
Snow is just as cold as ice, but the air it contains makes it a good insulator, and thus not as good at sucking out heat (unless air/fluid moves through it). Ice beats gel for heat absorption. Ice is hard to beat for amount of cold. Freezer packs could be made to be colder, but then might frost the food. Clear ice isn't inherently colder than cloudy ice but it melts slightly slower - more ice, less air... igloos are not made of ice, you'd freeze! The blocks are packed snow, ~1/4 the density of ice. Also, in cold weather it is the freshly-cut edges (broken snow crystals) that are most responsible for sticking the blocks together. Not to be confused with the melting of ice which can hold it together. When ice blocks are placed on top of each other the weight/pressure of the block causes the ice to slightly melt. This is called regelation. The water layer now refreezes thereby cementing the ice blocks together. The heat capacity of water is substantially higher than the heat capacity of air. The heat given off by people inside igloos can substantially warm the air inside (helped out by the fact that snow is a great insulator). But because the snow/ice/water that makes up the igloo structure has so much more mass and has such a higher heat capacity than the air inside, the igloo melts slowly. Snow has only 1/10 of the mass of an equivalent volume of water. It also has a lot of trapped air (90-95% of its composition). But for it to conduct heat effectively, it has to undergo a phase change. It takes a lot of energy to melt snow. If the walls are too thick, the inside of the walls will not be able to give away any heat they absorb from the people and lamps inside the igloo so the inside of the walls will melt a bit until the walls thin out enough that it reaches an equilibrium point, where the warmth absorbed from inside is exactly lost to the outside through the walls and no further melting occurs. Electrical resistance or thermal resistance: Snow consists of ice crystals and air. It turns out that water is a actually a poor electrical conductor, and frozen water (ice) is an even poorer electrical conductor.
Since air is also a very poor electrical conductor, it shouldn't be surprising that the combination is a very poor electrical conductor... and thus a good insulator. In cold climates snow is often found covering the high-voltage insulators in electrical power systems with no arcing or flashovers since it behaves as an insulator. Snow is also a great thermal insulator due to the presence of entrapped air spaces in the snow matrix. And the snowflake crystals prevent convection cells forming. Animals build "caves" inside snow banks to help keep warm. The snow near the ground is much warmer because it is more near to the low layer of ground and this is the best place for the animals to hide in winter. This snow acts as the best natural insulator.
Salt melts ice down to ~0F. The salt plus ice helps cool at first, but then impedes at ~0F (as slush refreezes); the rest just gets in the way of the cooling.
The effectiveness of the evaporative cooling effect of a wet paper towel around a can in the freezer, speeds cooling at first, then cooling slow as towel freezes or dries outer.
Water freezes into very pure ice, forcing almost all the dissolved substances out. This works for concentrating maple sap and ethanol as well as for salt. Yes, brine can drain out of ice over time.
Ice on top provides more-even cold
What makes "fresh ice" better?
Marketing?
Glacial ice fans disagree.
Water molecules migrate and stick at just below 0C. And external temp swings can melt and refreeze ice that is stored just around 0°C/32°F
- Is clear ice inherently colder than cloudy ice?
No.
In regards to microbes surviving in ice in Antartica, "the organisms survive in various ways, mostly by taking advantage of minuscule cracks in the ice containing flowing water." Is this the same thing as the ice having a pre-melted layer of water on it? Whats causing it to flow? Salt keeps the water in the crack liquid?
Metal and ice can get equally cold. They get as cold as the freezer they're in. Ice has a greater heat capacity than most metals, meaning it stays cold for longer, and there is a large latent heat when it melts, which means it absorbs a lot of heat from the ambient water without changing its own temperature as it melts. This allows it to cool down water by warming and melting more than the same size cube of metal could. To put a number on things, the specific heat capacity of water is about eight times larger than that of stainless steel. And that's leaving aside its very high latent heat of fusion.
Metal's higher density would largely offset its lower specific heat capacity for cubes of equivalent volume. Water still has the edge over metals even on a per volume basis, but it's not the factor of 8 that one gets on a per mass basis. For cubes of the same volume, the factor is more like 1.2 or 1.3 depending on the metal. The latent heat contribution from melting ice, on the other hand, would be roughly triple that from the heat exchanged in warming the ice to its melting
point and then to room temperature, with no
counterpart from the metal cubes. Therefore, I think that latent heat is the real issue to dwell on. But the catch with latent heat is that it, by definition, is absorbed when the ice melts. And when very much ice melts, it makes the drink taste flat. Hence the whiskey stones mentioned by others, made possible (though perhaps not convenient) by the higher density of metals as noted above.
The density of the metal cubes has another
aspect: steel weighs about 8 grams per cubic cm, and water 1 gram (8kg and 1kg per liter). Meaning that a mojito and some other ice applications could be unwieldy. Also, hot water rises. Due to its low density, ice also rises, meaning that the hottest water is always in contact with ice. Metal would settle at the bottom, potentially not cooling the top of a tall glass as well. But actually the highest density of water is at 4°C, so the ice could be in contact with the coldest water.
Other substances that expand on freezing are
silicon, gallium, germanium, antimony,
bismuth, plutonium and also chemical
compounds that form spacious crystal
lattices with tetrahedral coordination. But do they also expand before freezing?
It's a huge effect for the ice to be on top. Ice
cubes on the bottom of a glass melt about 3x
slower. So 3-5x slower cooling, which means
roughly 3-5x smaller temperature drop. Melting 3-5x slower essentially means 3-5x slower cooling, which means roughly 3-5x less temperature drop. The large majority of the energy ice absorbs is through the melting process, while the temperature change makes a very small difference. Melting isn't a byproduct of the ice warming. The melting itself is the mechanism that cools your drink. The ice
warming is just a side process until you reach the melting point that cools a small amount. Then it remains at a constant temp while it cools your drink through heat of fusion.
I would say significant (ice on top). One aspect of why ice does a good job of cooling water is that the water at the top of the column that gets cooled by the ice, falls to the bottom, creating a
convection current that constantly brings
warmer water to the top to be cooled, keeping a
fairly uniform temperature in your glass. With
the cooling source at the bottom of the glass,
you'd get a temperature gradient, driven by the
ability of the water to conduct heat. Convection
transports heat better than conduction, so the
effect could be noticeable. To add to this, with metal cube drink's temperature would rise gradually. Where with ice melting, the drink's temperature would gradually falls and stay there while the cube melts.
It is quite literally the process of melting ice that absorbs heat from the drink. No melting, you'd get comparatively almost no cooling from the ice. The ice increasing in temperature does nearly nothing to the temperature of a drink. It's basic science that the heat of fusion is what does most of the cooling when you put ice in a drink. Not sure what you're on about. The process of melting itself takes most of the energy from your drink and cools it. The same principle is used for most physical (not using electricity) cooling applications. Gel packs, liquid nitrogen, etc. They are effective
because of phase change. Your "ice absorbs the heat and then melts" is actually talking about the phase change itself, which is melting.
You can cool without a phase change, but you get relatively little cooling, this is THE reason why ice cubes are still more precelant than metal cubes for cooling drinks. Refrigeration systems are the most popular method of cooling, and they are completely based around the phase change of the refrigerant within the system. The refrigerant is changing from a gas, to a liquid, back to a gas within the system. You would have nowhere near the same cooling capacity if it only pumped a liquid through the system without any phase changes.
Diffusion says water in contact with
the ice will drop to and stay at 0 C because any additional heat transferred to the water will go toward melting the ice. The 100% surface contact with the liquid makes this even easier. Heat isn't going to diffuse out of the liquid into the environment, because the environment is warmer. With enough contact and bulk, the inside of the system isn't going to increase in temperature until all the heat of fusion is absorbed first. Phase changes eat a lot of energy.
You drop cube of ice into water, the water that's already there won't be at 0 C, but all the water that used to be ice would start at 0 C and quickly warm up. Ice cube will never be above 0 C, it will change states into water before it warms up above 0 C. Practically, no one is trying to cool their coffee with ice. You have a cup that's half or more ice, you poor 20C water in it. Water fairly quickly drops close to 0 C and all the water that used to be ice will start out at 0 C, keeping the drink "cold". As ice melts (like said, change of state takes a lot more energy than just transfer of heat from one part of liquid to another) and continuously adding 0 C water to your drink it will stay very close to 0 C until a large portion of the ice is gone. The latent heat contribution from melting ice, on the other hand, would be roughly triple that from the heat exchanged in warming the ice to its melting point and then to room temperature, with no counterpart from the metal cubes. Therefore, I think that latent heat is the real issue to dwell on.
Metals also have a latent heat of fusion....
The part about ice not going above 0C is correct...
At the density of water, we gain roughly one atmosphere pressure for every 10 m, or 100 atm per kilometer, so an 11 km deep trench would have over 1000 atm pressure.
But an interesting fact about water is that it probably has the highest density at around 4 degrees celsius. This might enable it to give you a different "feel" if you keep it on your tongue? Most fridge or chillers would chill water up to around this temperature.
Heavier atoms tend to produce denser solids, but bond length is also critical. Molecular weight has very little to do with density, buoyancy is simply the difference in density between something and what is immersed in, times the volume of the something.
Most glacial ice is at least as clear as most ice cubes. But it usually comes in much bigger pieces that show off its intrinsic color better than a small piece would. Glacial ice starts out as fairly porous snow, but by the time it becomes deep glacial ice, the air bubbles are greatly compacted, but it is still not as dense as ice made from boiled water or several-times-refrozen water.
Yes, water freezes into very pure ice, forcing almost all the dissolved substances out. This works for concentrating maple sap and ethanol as well as for salt. Yes, brine can drain out of ice over time. This works for concentrating maple sap and ethanol as well as for salt. Yes, brine can drain out of ice over time.
Unless ice cubes are individually wrapped, sticking together is about whether they've been allowed to partially thaw and refreeze, not whether they are "premium?"
Ice will also freeze to itself (basically a diffusion bond) over time, especially with a bit of pressure. I would not expect premium ice to be any different in this regard.
With cocktails presentation is one of the most important things. If you are taking the time to make sure everything else is perfect might as well make sure the ice is also perfect.
Snobby cocktail bar with obscure ingredients and lots of theater? Gotta include fancy ice. Local pub? Who cares? Somewhere in between? Just can't taste bad and needs to be dense enough to do it's job
I think it would be somewhat important if your goin got a cocktail bar sort of thing where the cocktails are the centerpiece of what your serving. But if your just a normal restaurant serving cocktails I wouldn't be too worried about it. How expensive is the cocktail?
directional freezing. In essence; you inhibit freezing on all sides but one in order for the trapped gasses that are usually trapped in the ice to escape from one direction. meaning you get an ice clearer than one frozen from all directions at once.
the big clear ice cubes that you see in bars don't come from ice machines as you know them; most will have come from a giant block of ice produced in a large and very expensive Clinebell machine, which takes a few days to generate and then needs to be broken down into manageable chunks. For a lot of bars this is too much work, so they outsource to companies that can provide pre-cut cubes, collins spears, and so on. If you want to achieve the same results at home, you'll need to either use a Wintersmiths product or similar, or set up an insulated cooler in your freezer and break down the resulting block.
Saturated (dry) steam results when water is heated to the boiling point (sensible heating) and then vaporized with additional heat (latent heating). If this steam is then further heated above the saturation point, it becomes superheated steam (sensible heating).
Superheated steam - Wikipedia
Water is adhesive and the weight of the water pulls the other water. The air breaks that.
Most toilets utilize a siphon to empty the water when the level rises quickly enough to create a seal in the top of the "U"-bend. The siphon process then carries the water down the pipe until air enters and the siphon is broken.
Ice is a mineral. It freezes in the hexagonal crystal system. Think about it like snowflakes. They are frozen six sided hexagonal crystals composed of frozen water. Another interesting fact is that frozen water like in a lake is natural ice where as frozen ice cubes from your refrigerator are considered synthetic ice.
One of the weirdest aspects of water is its unusual density. Normally, liquids become increasingly dense as they are cooled down, but water reaches a maximum density at about 4 degrees Celsius (39.2 Fahrenheit).
Below this point it is less dense, so when it freezes and becomes ice at 0 degrees Celsius (32 Fahrenheit), the ice is less dense than the water. This is why water ice floats, and bodies of water freeze from the top down.
But that's not all. Water also has really high surface tension - aside from mercury (https://www.sciencealert.com/mercury), it has the highest surface tension of all liquids. This is what allows water spiders to skate across the top.
To top it all off, water also has an unusually high boiling point, and the fact that so many chemical substances dissolve in it is also really peculiar, if we compare it to other liquids.
At room temperature and as ice, water has a tetrahedral arrangement (https://phys.org/news/2013-02-scientists-tetrahedral-molecular.html)
of molecules, which means every water molecule is bonded to four others in a rough pyramid shape.
Iceberg ice (and other glacial ice) that is more than a few thousand years old is generally free from modern pollutants, but other than that it is mostly a marketing gimmick.
Most minerals in mineral water are pretty stable, having already had many years in which they could react if they wanted to. However, the plastic bottle can indeed deteriorate, especially if exposed to heat or sunlight. If you leave a bottle of water in the car on a hot day, even if you let it cool afterward it will taste plasticky, mineral water in a glass bottle should not have an expiration date.
