The type of liquid surrounding an ice cube changes how fast it melts, and the differences can be dramatic. In one controlled experiment, a submerged ice cube in salt water melted four times faster than one submerged in plain tap water, while a floating ice cube in that same salt water actually melted slower than one floating in tap water. That counterintuitive split hints at just how many physical forces are at play: the liquid’s temperature, its density, whether it contains dissolved substances, how those substances affect the flow of warm liquid around the ice, and even whether the ice floats or sinks. The short answer to the question is yes, the liquid matters enormously, but the reasons are more complex and surprising than most people expect.
Salt Water and the Floating Paradox
Salt water is the liquid most people think of when they imagine speeding up ice melting, and with good reason: salt lowers water’s freezing point and changes its density. But the relationship between salt concentration and melt rate is not a simple “more salt equals faster melting.” Research consistently shows the effect is non-monotonic, meaning the melt rate first decreases as you add salt, reaches a minimum, and then starts climbing again at higher concentrations.1Journal of Fluid Mechanics. Ice melting in salty water: layering and non-monotonic dependence on the mean salinity This happens because salt affects two competing forces. On one hand, saltier water is denser, which changes the buoyancy-driven currents that carry warm liquid toward the ice surface. On the other hand, salt creates layering in the water that can actually insulate the ice by suppressing the natural mixing that would otherwise bring warmer water into contact with it.
A particularly striking demonstration of this comes from experiments where ice cubes were placed in beakers of tap water and sodium chloride solution, both starting at 20°C. When the ice cubes floated freely, the one in tap water melted about 25% faster than the one in brine. But when both ice cubes were weighted down so they sat on the bottom, the brine cube melted four times faster than the tap water cube.2Chemical Engineering Research and Design. Heat Transfer Characteristics of Ice Melting in Water and Salt Solutions The explanation lies in convection. When ice floats, the cold meltwater (which is fresh and less dense than the surrounding brine) forms a stable layer around the ice that acts like a blanket, slowing heat transfer. When the ice is submerged at the bottom, the geometry flips: the cold meltwater rises away from the ice, continuously replaced by warmer brine, and the melting accelerates dramatically.
This same non-monotonic pattern has been confirmed for vertical ice surfaces as well, where increasing salinity initially slows melting until a balance point between thermal and saline buoyancy effects is reached, after which the melt rate climbs again.3Journal of Fluid Mechanics. Buoyancy-driven flow regimes for a melting vertical ice cylinder in saline water For a kitchen experiment, this means that a lightly salted glass of water might actually melt your ice cube more slowly than plain water, while a heavily salted solution could speed things up considerably, depending on whether the ice is floating or held under the surface.
Sugar Solutions and Sweet Drinks
Sugary liquids affect ice melting differently from salty ones, largely because sugar molecules are much larger than salt ions and change the liquid’s physical properties in their own way. Research on sugar-water solutions shows that adding sugar increases the liquid’s ability to absorb heat compared to plain water.4Ilorin Journal of Science. Comparison of Heat Absorption and Retention Capacity in Fresh Water and Sugar Water Solutions That sounds like it should make ice melt faster, and in some conditions it does. But sugar also makes the liquid thicker and more viscous, which slows down the natural circulation currents that deliver warm liquid to the ice surface. These two effects pull in opposite directions.
In practice, if you drop an ice cube into a glass of cola or juice versus a glass of plain water at the same temperature, the soda or juice will often melt the ice at a somewhat different rate. The sugar content slightly lowers the freezing point (though much less than salt does at equal concentrations by weight), and the increased viscosity resists the swirling convection currents that are the main engine of melting. The net result depends on sugar concentration and the liquid’s starting temperature. Highly concentrated sugar syrups, like those used in cocktails or dessert preparations, can slow convective mixing enough that ice lasts noticeably longer than it would in water, even though the syrup itself may be warmer.
There is another factor at play in carbonated drinks. The bubbles in a fizzy soda stir the liquid around the ice, breaking up the cold boundary layer that otherwise forms on the ice surface. This agitation can partially offset the viscosity effect, meaning a carbonated sugary drink may melt ice faster than a flat sugary drink of the same composition. Practical experience bears this out: ice in a freshly opened can of soda seems to shrink faster than ice in a glass of flat juice, even when both start at the same temperature.
Alcohol and Antifreeze-Type Liquids
Alcoholic beverages and antifreeze solutions represent a different category entirely because these liquids can remain liquid well below 0°C. When ice meets a liquid whose freezing point is far below zero, the ice dissolves into the surrounding liquid rather than simply absorbing heat and transitioning from solid to liquid water. The rate at which this happens depends heavily on both the concentration of the solute and the temperature of the liquid. In ethanol and ethylene glycol solutions, the dissolution rate of ice increases exponentially as the liquid temperature rises. At −5°C, for instance, a 60% ethylene glycol solution dissolved ice at a rate of about 0.68 grams per minute; at −50°C, that rate dropped to just 0.006 grams per minute.5Polar Science. Ice drills recovery using chemical deicers Ethanol solutions dissolved ice slightly faster than ethylene glycol solutions at the same concentration and temperature.
For anyone making cocktails, this has real implications. A spirit like vodka (roughly 40% ethanol) is a powerful ice melter even when chilled, because the ethanol drastically lowers the freezing point and the remaining liquid water acts as an efficient heat-transfer medium. The latent heat of fusion of ice in ethanol solution is also affected by temperature in ways that differ from other antifreeze agents like propylene glycol or ethylene glycol.6International Journal of Refrigeration. Effect of temperature on the effective latent heat of fusion of ice in aqueous solutions In plainer terms, the energy cost of melting ice changes depending on what the ice is dissolved into and how cold the mixture is, which makes predicting melt rates in mixed drinks more complicated than it seems.
Wine and beer, which contain much less alcohol than spirits, behave more like slightly modified water. Their lower alcohol concentration means the freezing point depression is modest, and the dominant factors in ice melting are the liquid’s temperature and how well convection currents can circulate warm liquid past the ice. A glass of room-temperature red wine will melt an ice cube faster than cold white wine, and the alcohol content matters less than the temperature difference.
Why Convection Is the Hidden Driver
Across all of these liquids, the single most important mechanism controlling melt rate is not the liquid’s chemical identity but how effectively it circulates warm fluid toward the ice surface. This process, known as natural convection, is driven by density differences in the liquid. When ice melts, it creates a layer of cold water right next to its surface. If that cold layer sits stably in place (because it is less dense than the surrounding liquid, as happens when ice floats in brine), melting slows. If the cold layer is continuously swept away and replaced by warmer liquid, melting accelerates.
Numerical modeling of ice melting in water shows that the temperature of the bulk liquid is the dominant variable in determining how fast heat reaches the ice surface, and that convection currents driven by the temperature difference between the ice and the surrounding liquid are the main transport mechanism.7International Communications in Heat and Mass Transfer. A simplified numerical model for melting of ice with natural convection When you add dissolved substances to the liquid, you introduce compositional buoyancy on top of thermal buoyancy. Research using ice-water and frozen ethanol-water systems has shown that these compositional flows, along with surface tension effects at the melting interface, can significantly change the melting behavior compared to a system driven by heat alone.8International Journal of Heat and Mass Transfer. Study of melting mechanism of a solid material in a liquid
This is why stirring a drink makes ice melt faster regardless of what liquid is in the glass. Stirring forces warm liquid past the ice surface at a rate far higher than natural convection alone could achieve. It is also why the shape and position of the ice matter so much. An ice cube sitting at the bottom of a glass is surrounded by liquid that convects differently than one bobbing at the surface. In salt water especially, the position of the ice relative to the liquid’s density gradients can flip the melt rate by a factor of four, as the weighted-versus-floating experiments demonstrated.
How Ice Shape Interacts with the Liquid
The geometry of the ice itself interacts with the liquid to change the melting timeline. A standard cube has more surface area per gram than a sphere or cylinder of the same mass, which means more of the ice is in direct contact with the warm liquid at any given moment.9International Journal of Thermal Sciences. Exploring ice melting dynamics in beverageware The practical consequence is that ice cubes chill a drink faster but also dilute it faster. Spherical ice molds, popular in whiskey culture, exploit this tradeoff: the sphere has the lowest possible surface-area-to-volume ratio, so it melts more slowly and dilutes the drink less over time.
This geometry effect compounds with the liquid type. In a viscous liquid like a sugar syrup or a thick smoothie, the boundary layer of cold meltwater clinging to the ice surface is harder to displace. A sphere in such a liquid melts especially slowly because the combination of low surface area and poor convection creates a double insulating effect. In a thin, warm liquid like hot tea, even a large sphere of ice disappears quickly because the aggressive convection overwhelms the geometric advantage. Bartenders who care about dilution rates intuitively understand this: they choose large, dense ice for spirits served neat (where you want slow melting) and crushed ice for cocktails that benefit from rapid chilling and some dilution.
Common Misconceptions in Kitchen Experiments
The most widespread misconception about ice melting in different liquids is that salt always makes ice melt faster. As the research shows, this is only reliably true when the ice is submerged and the salt concentration is high enough to have passed the non-monotonic minimum. A lightly salted solution, or one where the ice is floating, can actually slow melting compared to plain water. Anyone who has run a science-fair experiment comparing ice in salt water versus tap water and gotten confusing results likely stumbled into this phenomenon without realizing it.
Another common misunderstanding is that the liquid’s temperature is the only thing that matters. While temperature is certainly the most powerful single variable, two liquids at the same temperature can produce very different melt rates because of differences in density, viscosity, and the convection patterns they generate. A glass of room-temperature milk and a glass of room-temperature water will melt ice at different rates, even though neither is notably warm. The milk’s higher density and different viscosity change the fluid dynamics around the ice.
A third misconception shows up in discussions about oil. People sometimes assume that oil, being a liquid at room temperature, should melt ice at a rate comparable to water. But oil and water are immiscible, oil has a much lower thermal conductivity than water, and oil’s density relative to ice creates a situation where the ice tends to sit at the oil-water interface (if any water is present) or simply float with minimal contact. Ice in pure cooking oil melts far more slowly than ice in water at the same temperature, not because of a chemical interaction but because oil is simply bad at delivering heat to the ice surface.
What Happens at the Boundary Layer
At a microscopic level, the melting process is controlled by what happens in the thin layer of liquid right next to the ice surface. As ice melts, it produces a film of nearly freezing fresh water. In pure water, this cold film is slightly denser than the ice but lighter than the warmer water farther away, so it sinks gently and is replaced by warmer water from above. The process is relatively orderly.
In salt water, the physics of this boundary layer become more complex. The fresh meltwater is less dense than the surrounding brine, so it tends to rise, creating a stratified layer that resists mixing. Increasing salinity strengthens this stratification, which is why the melt rate initially drops with added salt. But at higher salinities, the overall density difference between the warm brine and the cold meltwater becomes large enough that turbulent mixing breaks through the stratified layer, and the melt rate climbs again.10Journal of Fluid Mechanics. Meltwater transport and mixing-layer growth near the ice–ocean interface Numerical simulations show that turbulence in the bulk liquid continuously drives meltwater transport, but the interfacial boundary layer acts as a gatekeeper, regulating how much of that fresh meltwater actually reaches the turbulent region beyond.
This boundary-layer behavior helps explain why real-world ice melting rarely matches simple predictions. The interplay between thermal gradients, density gradients, and the dissolved contents of the liquid creates a system where small changes in conditions can tip the balance between slow, stable melting and fast, convection-driven melting. It is one of the reasons that researchers still publish papers on ice melting in various solutions: the physics are genuinely complex despite the apparent simplicity of dropping ice into a glass of liquid.
Industrial Applications of Controlled Ice Melting
The science of ice melting in various liquids is not just a curiosity for science fairs and cocktail bars. It has direct industrial relevance in thermal storage and refrigeration systems. Ice slurries, which are mixtures of small ice particles suspended in a liquid (often water mixed with an antifreeze agent like ethylene glycol), are used as secondary refrigerants in cooling systems for buildings, food processing, and industrial applications. These slurries exploit the high latent heat of ice melting to absorb large amounts of energy during phase change, making them more efficient than single-phase liquid coolants.11PubMed Central. ICE SLURRY APPLICATIONS
The performance of these systems depends directly on how fast the ice melts in the carrier liquid. In tube-flow experiments with ice slurry made from a 6.5% ethylene glycol solution, the heat transfer rate increased with both the flow rate of the slurry and the fraction of ice in the mixture. At low flow rates, increasing the ice fraction above 10% produced a sharp jump in heat transfer efficiency, but at high flow rates the ice fraction mattered less because the forced convection was already doing most of the work.12International Journal of Refrigeration. Heat transfer characteristics of the ice slurry at melting process in a tube flow The concentration of antifreeze in the carrier liquid also plays a role: higher antifreeze concentrations affect the temperature gradients inside the slurry during melting, changing how uniformly the ice particles melt and how efficiently the system absorbs heat.13Thermochimica Acta. DSC study and computer modelling of the melting process in ice slurry
These industrial findings echo the kitchen-scale observations: the dissolved contents of the liquid, the rate of fluid flow past the ice, and the temperature difference between the ice and the liquid are the three knobs that control melting speed. Engineers designing cooling systems and bartenders designing cocktail programs are, in a real sense, solving the same heat-transfer problem with different tools and different stakes.