How Long Does it Take Water to Freeze? The Complete Science Behind It

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Ever wondered how long it actually takes for water to freeze in your freezer? Been waiting for your next batch of ice cubes to be ready and not knowing how long to wait? Well, fear not. This is an easy guide to explaining how long it usually takes and the factors that affect the speed at which it takes water to freeze.

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ice cube

Table of Contents

When Water Freezes into Ice, How Long Does it Take?

There are many factors that need to be considered when looking at the speed at which water freezes.

Before that, let us rewind back to elementary school science for a moment to remind ourselves of the science behind the changing of states.

The Science Behind Water Freezing

The freezing point of water is 0 degrees Celsius, or 32 degrees Fahrenheit. Going back to the physics we all learned in school, let’s remind ourselves of the process. The freezing process is similar to that of the boiling process (but of course, the opposite).

Water, like any other liquid, can be seen as constantly moving molecules, which gives it its fluid state. The heating process occurs when energy is applied to the molecules causing them to speed up and travel much quicker. The same is true for the opposite, When the temperature drops, they begin to move slower.

So, when these molecules start to slow down, they become sluggish and begin to hook together, which results in the water to start solidifying into a solid crystal. Thanks to its crystalline solid state, water (unlike many other liquids) expands in its solid state, causing it to be denser than when it was a liquid.

What is the Temperature at Which Water Freezes?

While the freezing point of water is 32 degrees Fahrenheit, there are a few different factors that come into play.

For example, a significant body of water, like a lake or deep pond will take a couple of weeks to freeze over. Whereas a puddle in the same conditions may only take a couple of hours.

water drop

Why does it take water so long to freeze?

There are a few different factors which come into play when trying to freeze it, which I will cover in this next section:

The Volume of Water Available

The less water that is present, the quicker the water will freeze. When there is a lower volume, there is a lower mass: this then means that less energy is required to bring down the temperature of the interior molecules, which are not touching the surface. This then results in a faster freezing period.

The Temperature of the Water

Of course, the temperature plays a large role in how long water takes to freeze. The lower the temperature surrounding the water is, the faster it will freeze.

The Thickness of the Water

The thicker that your water is, it will take longer to freeze. So, by that logic, if your water is salty, it will actually take longer to freeze than freshwater will.

How does Altitude Affect Water Freezing?

Altitude affects the freezing point of water, and higher altitudes have a lower freezing point.

However, even if you’re on Mount Everest this would only lower the freezing point by 1.8 degrees Fahrenheit. This is due to low atmospheric pressure at high altitudes.

a lot of ice

How Long Does a Typical Ice Cube Tray Filled with Water in a Standard Freezer Take to Freeze?

In a basic household freezer, it will typically take approximately 3-4 hours to freeze water in an ice cube tray. This is the average time it will take to freeze ice cubes in a 12-square-space ice cube tray.

While water freezes at 0 degrees Celcius, or 32 degrees Fahrenheit, the actual time it takes to freeze will be determined by a number of other factors which come into play and may cause your freezer to take longer or shorter.

Container Size

Again, referring to the volume of water you’re trying to freeze, a smaller container will take a shorter time to freeze.

So, if you have small ice cubes, then they will be ready quicker. Larger ice cubes for cocktails such as negronis or an old-fashioned take more time.

Container design

The design of the ice tray also plays a role in how long it will take to freeze. Some ice trays have dividers between each of the tapered cubes, while others have air spaces between the empty cubes.

The design of the first ice tray with dividers leaves a smaller surface area for the ice cube. This is due to the air space between each of the cubes in the second one, where the design of the first tray just has separators in between each of the cubes.

Therefore, because the surface area is larger in the second ice cube tray, it will freeze faster than the first. The surface area of the ice cube is larger in the second ice cube tray allowing more water to freeze from the outside in.

The temperature in the freezer

Another factor that needs to be considered is the temperature of the freezer.

The average temperature for home freezers is usually 18 degrees Fahrenheit. This will fluctuate depending on a few different factors, such as opening the door of the freezer often, loading it with room temperature foods, or even warm foods.

If you are trying to make ice cubes quickly, try your best to leave the freezer food closed as much as possible.

freezer

How Long Does it Take for Water to Freeze in a Dedicated Ice Machine

Countertop ice makers work similarly to commercial ice machines, they are just smaller and for use at home. These machines have the ability to freeze water much faster than standard refrigerator-freezers.

These can make ice in as little as a couple of hours.

On the inside of the ice maker, there is a metal tray which is connected to a compressor coil. The refrigerant is then pumped by the compressor, which is then fed through the metal coils, allowing the metal trays to freeze. This is called direct freezing, which is the same type of freezing that is used in large ice makers.

Unlike the way you usually fill the tray with water, the dedicated ice maker sprays water onto the tray. The tray is already at freezing temperature, therefor the water settles on the tray and almost instantly ice crystals begin to form. This allows the water to freeze much faster than in your freezer, which can take hours to do the same job.

Whats more, an ice machine with this function can produce ice cubes that look perfectly clear because there are no imperfections in the ice. This can happen because it is frozen equally from the inside out. This makes them ideal for cocktails and impressive cold drinks.

This compares to standard freezers, which usually produce ice cubes that have an unappealing white cloud in the center of the cube.

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In a Standard Freezer, How Long Will a Bottle of Water Take to Freeze?

A standard 16 oz. plastic bottle of water which is at room temperature will usually take 90 minutes to freeze in your standard freezer.

This of course is dependent on the size of the bottle, but smaller bottles of water will freeze quicker than larger bottles.

For example, a water bottle that is 8 oz. will take approximately 45 minutes to freeze in a regular home freezer, whereas water in a 1-liter plastic bottle will probably take around 2 hours to freeze.

How Long Does it Take to Freeze a Gallon of Water

Its going to take a long time to freeze a gallon of water, particularly depending on the container you’re storing it in.

It will most likely freeze if kept overnight in a powerful freezer.

It is important to consider other factors previously mentioned as well if planning to freeze this amount of water.

How Long Does it Take for Water Pipes to Freeze

Pipes will need a sustained period of time to freeze through. For example overnight if the temperatures have dropped below 32 degrees Fahrenheit and your pipes are unprotected. It could take 6-8 hours for your pipes to freeze.

Saying that, as a general rule, the ‘temperature alert threshold’ for freezing pipes is roughly around 20 degrees Fahrenheit.

How Long Does it Take for a Cup of Water To Freeze

Again, depending on the cup size, it will take roughly 90 minutes for a 16-ounce plastic water bottle to freeze in a standard freezer, which a standard 8-ounce bottle of water will take roughly 45 minutes.

How Long Does it Take Room Temperature Water To Freeze

For water that is at room temperature, it will take roughly 1-2 hours for a freezer to cool this water to freezing. It must be taken into consideration that the vessel will play a role in the speed of freezing too.

This will determine the volume of water that is present and the surface area of which the water has, which directly affects the speed of the freezing process.

frozen water

Speeding up the freezing process

Found yourself with no ice at home and need it quickly, say you’re hosting a party or its a hot day. You can speed up the freezing process, even if it takes an average of 3-4 hours for the water to freeze by following a few of these steps:

Chill the Ice Cube Trays Before Using Them

An easy way to start is by chilling your ice cube trays before use. I always just store my ice cube trays within the ice cube tray section of my freezer, even when they don’t have any water in them. This will help speed up the process because of the already cold surface of the ice cube tray.

Use Water That Has Been Bottled or Distilled

Using bottled water over tap water means that the water will have less contaminants within the water. These contaminants can interfere with the crystallization of the water molecules. Bottled or distilled water has has these contaminants removed, therefore by logic, the water should freeze faster.

Using a cookie sheet or cupcake baking tray means that the surface area of the water has been largely increased in comparison to that of a plastic water bottle.

Better yet, use one that is metal!

If you have a cookie sheet or cupcake tray that is metal this will work even better due to the conductive properties of metal.

You could even use a flat metal tray to freeze the water as this would again hugely increase the surface area of the water, which we now know plays a hugely important role in the speed of freezing water.

The conductive properties of metal will allow the metal tray to cool down much quicker than that of plastic and help the water to freeze faster. Think of tongues sticking to metal poles in freezing temperatures – its a good example of how much metal holds this energy within itself.

You’ll notice when removing the tray from the freezer that you might need a tea towel to protect your hand! You could just use a rolling pin or the back of a wooden spoon to smash up the ice on the tray. And voila, you’ll have perfectly good ice, quick time.

Boil the water before freezing

How long does it take for boiling water to freeze? The answer will surprise you! It is a scientific fact that boiling water before freezing will actually cause the freezing process to speed up. It is known as the Mpemba Effect.

This is because hot water cools faster because of the bigger difference in temperature between the water and the freezer. This helps it reach its freezing point before cold water reaches its natural freezing point.

Where a freezing point would also usually be governed by impurities, boiled water has had these bacteria, dust, and dissolved salts removed. This ensures that the freezing point remains that of the actual water.

stack of ice cubes

Freezing a plastic bottle

In order to do so more quickly, just follow these simple steps:

  1. Adjust the temperature of your freezer, this will most likely be from -24 degrees Celsius to -11 degrees Celsius. This can take a number of hours to adjust if it isn’t at that temperature already.
  2. Place your required number of water bottles into the freezer, and set the timer for 2 hours 45 minutes exactly.
  3. When you are removing the bottles, the water should still be liquid. but the temperature is actually below freezing. If the bottles have frozen over, then the temperature of your freezer was not at -11 degrees Celcius. You may need to fix the thermostat on your freezer.
  4. Give the bottle a strong jolt. You should see the entire bottle turn to ice. Opening the lid of the bottle may also start the freezing process.
    • If you have done the cooling process without the cap on, then you can start the freezing process by introducing a small bit of ice into the bottle. This will start the reaction.

Below is an easy-to-follow video that explains this concept!

FAQs

How fast does water freeze at -10 degrees Celsius?

For a 20-ounce bottle of water to completely freeze over, it will take approximately 5 hours to freeze over using warm water from the tap.
It will take approximately 3 minutes to freeze water spilled on the concrete.

How can I make clear ice at home?

Another way you can manually make your ice cubes clear at home is by boiling the water initially. This will remove any impurities from the water, and once it has frozen over, will result in perfectly clear ice cubes, great for fancy cocktails!

clear drinking glass with ice

Easy Freezy!

I hope this has answered your questions on how the different factors affect the freezing time of water. The most important ones are temperature, the surface area of your container, and the purity of the water.

If you were interested by this topic and would like to check out some other similar blog posts that I have written, just follow the links below!

If you have anything else to add, please let me know in the comments!

By Anna

Hey, I’m Anna; writer, editor and amateur cook extraordinaire! Food has been my life and my passion for the most of my life – it’s crazy to think I didn’t pursue a career in cooking. I’m obsessed! However, keeping cooking as an obsessive hobby has worked for me – my passion grows as the years pass by – maybe I wouldn’t say the same if it was also my day job! I hope you find cooking inspiration, entertainment and “stop and think interesting tid-bits” throughout my writing – and I’d love to hear from you if you’ve got anything you want to share. Food feeds the soul – so get eating!

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