How To Make Instant Soft Ice In A Water Bottle (Details + Videos)

Have you ever seen someone take a bottle of water and shake it, bang it or touch it with ice and it instantly freezes? Soft ice can either be a perfect snack on a warm summer's day or an entertaining ice trick to show your friends.

The science behind it is pretty simple if you know what you're doing, but it does take some practice or good timing to get it perfect. If you stick to it, you can be making the perfect snowcones at your next party or barbecue or impressing your friends by instantly freezing water. Let's see how you can make instant soft ice in a water bottle.

To make instant soft ice in a water bottle supercool the water bottles by placing it on its side in the freezer for approximately 1.5-2 hours. Get your water bottle out before ice crystal begin to form, the hit the bottle or touch it with ice and watch the entire bottle instantly freeze.

Instant soft ice is not difficult to make, but the term “instant” may be inaccurate. Though the ice crystals form instantly, there's quite a lot of preparation to do before that happens, which could take between 30 minutes and approximately two and a half hours depending on what method you use and how cold your freezer is.

It's also very easy to get wrong. Take the water bottle out too quickly and it won't freeze at all, take it out too late and it'll already be frozen. So timing is everything here.

Let's go through the steps, but first, let's see why exactly the soft ice crystals form in a water bottle.

Why Soft Ice Instantly Forms In A Water Bottle

Water requires two conditions to form ice crystals:

  1. Water will freeze at temperatures of 0oC (32oF) or lower. If those temperatures are not met, water simply will not freeze.
  1. When the water reaches the correct freezing temperature, it still requires a “nucleation site” to form the ice crystals. If there's nothing that could cause a nucleation site, your ice crystals won't start until the water gets much much colder. 

Supercooled water is water that has been cooled to the point where it should be freezing, but it is denied a nucleation site. This means you can have water that is below 0ºC (32ºF) but it hasn't frozen yet.

The moment when the necessary conditions are met and a nucleation site is introduced into the supercooled water, the ice crystals will instantly form before your eyes, even inside a water bottle.

Nucleation sites are usually impurities in the water, or they could be something solid like an ice cube.

The water could also create its own nucleation site if some of the water molecules are forced into the correct pattern for crystals to form around. This is why this must be done with purified water, like bottled water. It must be as free of impurities as possible. 

Steps For Making Instant Soft Ice In A Water Bottle

There are two steps to making your instant soft ice, but different ways to achieve each step. Let's look at them in detail:

Step 1: Super Cool The Water Bottle Without It Freezing

There are two methods to achieve this. The first is more straightforward but may take a long time, while the second is faster but more complicated.

Method A: Supercool Water Bottles In The Freezer

The freezer method differs in precision, which is why this method could take a long time to get right.

  1. Set your freezer at approximately 70 to 75% of its lowest temperature.
  2. Place your bottles of purified water inside the freezer. Place them on their sides for best results, and ensure that they are spaced out a bit and not touching one another.
  3. Close the freezer door and touch it as little as possible for an hour and a half.
  4. When the timer runs out, you can carefully open the door and check the bottles without moving them. If the ice crystals are white, the freezing process has gone too far, and you should restart, if not you can take them out and test them to see if they freeze on impact
  5. If they don't freeze, carefully close the freezer, leave it for another 10-15 minutes, and try again.
  6. Repeat this process until your water is supercooled and you can produce instant ice

You can also use an infrared thermometer to measure the temperature of the water to know whether or not it is supercooled.

Method B: Supercool Water Bottles In Salted Ice

This method is faster and much more precise but requires a bit more effort.

  1. Put fine ice in the bottom of a steel container, then add five teaspoons of salt to the ice.
  2. Put your bottle of purified water in the middle of the container, standing on the ice. The container should be high enough so that only the water bottle's cap sticks out over the top of the container.
  3. Add more fine ice around the bottle until about halfway up, then sprinkle five more teaspoons of salt over the ice.
  4. Repeat these layers of ice and salt until it's as high as possible. The bottle should be completely surrounded by ice and salt up to its cap. 
  5. Leave the bottle like this for about 30 minutes, checking on it regularly to ensure it doesn't freeze to eaerly.
  6. After 30 minutes, you can carefully take the water bottle out of the container. It should be supercooled and you can now perform the trick.

Step 2: Turn Water Into Soft Ice Instantly

Once your water has reached a supercooled state, you can use one of three methods to turn it into soft ice instantly:

Method A: Bang The Water Bottle

Giving the water bottle a gentle slap will force the water molecules to align into patterns that create nucleation sites and cause ice crystals to form.

This usually starts from the top of the bottle, closest to the cap, and moves down to the bottom, creating slushie chewable ice that is delicious.

Method B: Pour The Water Out Over An Ice Cube

An ice cube, or even shaved or crushed ice, will create a nucleation site for the ice crystals to form.

You can put ice in a container, slowly open the bottle, and pour the supercooled water out over the ice. Crystals should form as you pour it, creating instant soft ice.

Method C: Pour Water Into A Glass And Turn It Into Ice

Carefully open the water bottle and slowly pour it into a properly cleaned glass. There should be no impurities in the glass that could be nucleation sites.

Once the water has been poured into the glass, take an ice cube and touch the water with it. The water should freeze instantly to create soft ice.

Other Ways To Make Soft Ice In A Water Bottle

There are three other ways to make soft ice in a water bottle. These methods are not instant, which detracts from the impressiveness, but if you're simply looking for soft ice and you don't plan to impress anyone with it, these will work just fine:

  1. Freeze a bottle of club soda. The soda in the water will keep it from creating solid ice blocks, which means you get soft ice that's easy to crush.
  2. Freeze carbonated water. Like the soda, the carbonation will cause the water to freeze into crystals rather than as a solid block of ice, making it soft and easy to crush.
  3. Add sugar to the water. Sugar lowers the water's freezing point, which means that the ice will still be soft when it reaches the water's normal freezing temperature.
  4. More idea – Click here for more ways to make soft chewable ice at home.

Final Thoughts

Making instant soft ice in a water bottle is really simple if you understand the science behind it. With some practice, anyone can do it.

Use it to impress your family and friends or as a home science experiment. The added benefit is that you can then easily make snowcones for everyone to enjoy!