How do I chill drinks quickly?

Everyone reaches for the freezer, and the freezer is the slowest of the good options. The physics is worth thirty seconds of attention because it explains all the tricks at once: heat moves out of a drink into whatever surrounds it, and how fast depends on how well that medium conducts and how big the temperature difference is. Still air is a poor conductor; moving ice water is an excellent one.

Safety

Step by step

1. Use ice water rather than ice alone.A can buried in dry ice cubes touches the ice only at a few points. The same can submerged in ice water is in complete contact with a cold medium that conducts heat far better than air. Adding water to a bucket of ice roughly halves the time — it is the single most counter-intuitive and most effective step.
2. Add salt.Salt dissolved in ice water lowers its freezing point, so the mixture can sit several degrees below zero while remaining liquid. A couple of generous handfuls in a bucket makes a genuine difference. This is the same principle as gritting a road and as an old-fashioned ice cream churn.
3. Keep it moving.As the drink cools, a layer of slightly warmed water forms around it and insulates it. Stirring the bucket, or spinning the can, breaks that layer up and keeps cold liquid against the surface. Spinning a can for a few seconds at a time makes a measurable difference.
4. Use a wet cloth in a breeze if you have no ice.Wrap the bottle in a wet cloth or a damp piece of kitchen paper and stand it in a draught, or in front of a fan. Evaporation removes a lot of heat, and this works surprisingly well outdoors on a dry breezy day. It is the slowest of the good methods and needs no equipment.
5. Use the freezer only with a timer.The freezer works — it is just slow, because still cold air is a poor conductor, and it is the one method that ruins things. A can left in overnight splits and a glass bottle can shatter. Fifteen to twenty minutes for a can, and set an actual timer rather than trusting yourself to remember.
6. Choose the container shape.A thin aluminium can chills far faster than a thick glass bottle, and a wide shallow container faster than a tall narrow one, because both are about surface area relative to volume. If you have a choice, decant into cans or a wide jug.
7. Pre-chill the glasses too.A cold drink poured into a warm glass warms immediately. Glasses in the freezer for a few minutes, or rinsed with cold water and left wet in the freezer, keep a drink cold for much longer once poured.
8. Do not use ice made from warm water in a hurry.There is a persistent claim that hot water freezes faster than cold. It is unreliable and depends on conditions that are hard to reproduce, so for making ice quickly use cold water in a shallow tray, which gives the most surface area.
9. Keep the drinks box separate from the food box.Drinks are opened constantly and every opening dumps the cold air. A bucket of ice water for drinks, with the food cool box closed and undisturbed, keeps both jobs working.

Tips

• A damp paper towel wrapped around a can before it goes into the freezer speeds it up noticeably, because the wet layer conducts far better than the air gap around a dry can.
• Freeze some of the drink itself in cubes — squash, juice or coffee — so the drink is chilled without being watered down as they melt.
• A wet sock over a bottle, hung in a breeze, is the classic camping version of the evaporative method and it works.
• Salted ice water is cold enough to be uncomfortable to fish drinks out of. Use a scoop or wear a glove rather than plunging your hand in repeatedly.
• Do not put sealed carbonated bottles in a freezer at all beyond a few minutes. The pressure and the expansion together make bursting far more likely than with a still drink.

Common mistakes

• Burying drinks in dry ice cubes with no water — Contact is only at a few points and air fills the rest. Adding water puts cold liquid against the whole surface and roughly halves the time.
• Putting cans or bottles in the freezer and forgetting them — Liquid expands as it freezes, splitting cans and shattering glass. It is the one method that causes damage and injury, so always set a timer.
• Pouring a cold drink into a warm glass — The glass warms it immediately. Chilling the glasses takes a few minutes and makes a bigger difference to the drinking experience than another degree in the bottle.
• Leaving the food cool box open while getting drinks — Every opening exchanges the cold air. Keep drinks in a separate bucket of ice water so the food box stays shut.

Alternatives

• Ice water with salt, stirred: The fastest practical method. A warm can in a few minutes. Needs ice, water, salt and a bucket.
• Wet cloth in a breeze or in front of a fan: Evaporative cooling, no ice needed. Slower, works best in dry moving air, genuinely useful outdoors.
• Freezer with a timer: Slow because still air conducts poorly, and the only method that destroys the container if forgotten. Fifteen to twenty minutes for a can.
• Running cold water: Better than still air and worse than ice water. Reasonable for a bottle when there is no ice, and wasteful of water.
• Frozen fruit or reusable ice cubes: Chills without diluting. Useful for a drink you have already poured rather than for cooling a batch.

Questions people ask