Why Do Plastic Water Bottles Shrink? | Facts To Know!

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Written By John Roe Stephen

Have you observed any plastic water bottle shrinking when hot water is poured into it or for any other reason? You might be curious to find out why do plastic water bottles shrink in all cases? And you might also be looking for what prominent reasons could result in these plastic water bottles shrinking. No problem, because I am here to answer all your queries, and I will provide you with some of the best ones in this guide.

So, please keep pace with me and stay focused till the end. Because you will completely know why these plastic water bottles shrink and what are the reasons behind that happening?

So Basically, Why Do Plastic Water Bottles Actually Shrink?

When you find your plastic water bottle shrinking, it’s probably for several reasons. These reasons are pretty much known to everyone.

But since you need to know better, please look at all the possible situations that may result in shrinking these water bottles.

  • It gets squeezed or shrinks when you try to put hot water inside a plastic water bottle.
  • A water bottle shrinks when you hold it in your hand and put greater pressure on its walls.
  • Placing a water bottle in hot temperatures would also result in its shrinking. It includes direct sunlight and stuff like that.

Moreover, such shrinking happens because if that plastic water bottle is made with PET #1 plastic, it is not that durable.

This material cannot stand strong against forces, and when you even squeeze a water bottle like this with your hands, it shrinks. However, keep reading because you are going to find many other facts about these water bottles.

But if you want to know more about plastic bottles, read our plastic water bottle-buyer guide and get to know everything about them.

Why Does A Bottle Shrink When You Pour Hot Water In It?

A plastic water bottle usually gets squeezed or shrinks when you pour some recently boiled and hot water inside it.

But why does such a thing happen? Have you ever observed this reaction of your water bottle in case of contact with hot water?

Below, I am describing two processes to explain why this happens with a plastic water bottle? Please have a look!

One Process:

For most reasons, when a plastic water bottle is filled up with hot water, that hot water creates steam inside the bottle.

Such a thing results in letting a part of air outside the water bottle. However, when such a water bottle is closed with its lid, the steam eventually cools down, resulting in a quick condensing procedure.

As you know that some bottled air has been removed outside, such a thing created a vacuum. Ultimately, the water bottle got collapsed.

Second Process:

This process that results in a plastic water bottle shrinking has been contributed. But it would be a great and certainly the main effect when that water is not hot on a fundamental basis.

There will be no steam production at all. However, such a thing happens when that hot water heats the air inside the water bottle.

This increases the temperature, which ultimately happens when hot air expands into the water bottle.

Resulting of this, when you have closed the bottle, the air will cool down. And you will find this thing decreasing the actual volume of the water bottle. It will again create a vacuum that will shrink a plastic water bottle.

What Happens When You Put An Empty Plastic Bottle In The Freezer?

Let’s move toward the freezing part of what happens when a plastic water bottle enters a cold environment. Because in hot, it gets collapsed.

However, when an empty plastic water bottle is placed in a very cold freezer, it will start collapsing slowly, which will happen in itself.

It is similar to seeing a giant hand that might be crushing the water bottle from the outside. Such clasping will continue until the water bottle’s air gets cold at the same level as the air outside.

You would be amazed to know that this process takes only a few seconds and your water bottle collapses.

How To Fix Deformed Plastic Bottles?

Suppose your water bottle has shrunk for any reason, and you are asking yourself how to get it back?

Can you really un-squeeze a squeezed or shrunk plastic water bottle?

Is it possible to do so? And there could be many other questions like this. However, in the first place, you have totally lost that water bottle.

Because even if you would do the below process of taking it back into its original shape, there will be a high chance of mixing toxic plastic chemicals into the water bottle.

Therefore, to stay healthy and prevent the dangers of these chemicals, you must consider buying a new one instead of wasting your time on the older one.

But for any reason, you can apply the following method to get that water bottle back.

The Method Of Deforming Plastic Water Bottles:

Suppose you are considering deforming a plastic water bottle. In that case, you must have a mould with which those SodaStream water bottles are made of.

This begins by heating the plastic inside that mould. And then you have to blow some air into that plastic water bottle. Such a thing will give the water bottle its original shape.

Is It Safe To Drink From A Dented Plastic Bottle?

Not a problem if your plastic water bottle has got a dent. Because if it still has the space to keep some water and you still consider it leak-free, you can use it.

However, a plastic water bottle doesn’t cost you much. Having a dented water bottle is not something you would like to do or keep on your most thirsty journeys.

Instead, consider buying stainless steel or a new plastic water bottle that must come dent-free and in a new shape or design.

What Type Of Plastic Water Bottles Usually Shrink?

Whenever a plastic water bottle is made with PET (Polyethylene Terephthalate) such as those soda or water bottles, they tend to shrink pretty much when placed in hot environments.

Such plastic is BPA-free but cannot hold temperature resistance. This means you would always have to be extra careful while having a plastic water bottle in hot conditions or under hot temperatures.

Why Do Water Bottles Shrink Over Time?

A water bottle of plastic is only made to be used one or two times in case it is a single-use water bottle.

But if it is a reusable plastic water bottle, it might be used multiple times. However, whether you have a single-use plastic water bottle or a reusable one, both will start shrinking over time.

This happens because of many reasons; a plastic water bottle is exposed. These possible reasons could be as follows.

  • Water bottles start shrinking because they are not built with a heavy-duty material.
  • They shrink because of daily wear and tear.
  • Hot environments participate a great deal in making those water bottles shrink.
  • Moreover, when you have bought a water bottle from any local brand, it will not stay with you for a long duration. So, always consider buying a high-quality water bottle such as one made of stainless steel, glass, etc.

Final Thoughts:

In the end, I hope that you fully understand why do plastic water bottles shrink if you have read this guide up to this end. That’s simple and easy to understand. But still, I provided you with enough information to solve this query. Despite this, you should let me know if you come up with some new queries or don’t understand anything in this article. I will be here to help you and sort your problems out.

But anyway, thanks for reading and spending time. Take good care of yourself, and have a blessed day!





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