Have you ever wondered why tennis balls come in air-sealed pressurized cans?
This is to ensure that the balls stay fresh from the factory right up until they are opened.
By using these sealed cans, the ball’s pressure level is maintained.
You can assume from this that the balls will bounce just as well when they get to the court as they would have done in the factory they were made in.
Does this mean that if you leave an unpressurized can of balls alone, they will last forever?
Unopened tennis ball cans do not last forever. The general rule is that they are good for two years if not opened. After a couple of years have passed, micro air leaks will have caused the balls to lose pressure.
Having said that, it doesn’t necessarily mean that the balls are unusable after two years.
They just won’t feel as though they are brand new.
In this article I will discuss:
- Whether tennis ball tins can leak air
- How long an unopened can of balls can last
- If storing the cans in an ambient temperature will affect the shelf life of the balls
If you’ve just bought a new set of balls from a shop you’ve got nothing to worry about, otherwise, you probably should read on.
Do Tennis Ball Cans Leak Air?
Pressurized tins will do a good job of preventing excessive loss of pressure. However, what they will not protect the balls from is pressure loss altogether.
This is because of the effect of micro leaks.
Micro leaks are tiny gaps within the can that allow small bits of air to escape. If you use a set of balls within a year, you won’t notice a difference.
If you take out a set that has been lying in the basement for 10 years, the balls will feel pretty dead.
The reason they will feel dead despite remaining in a sealed can is this. Over the past decade, there have been loads of micro leakages.
Even though you won’t notice it short term, these leaks add up over the years and will eventually affect the performance of the ball.
Micro-leak refers to a leak that is so small you cannot notice it visually. It would be described as a leak that leaves no visible water drops in plumbing.
The water leaking is so tiny that it evaporates before you can see it.
While comparing plumbing and tennis balls cans may seem strange, the theory remains the same.
I’ve not personally played with balls that are over 10 years old. I once used a set of balls that were 7 years old. As I opened the can, they had that same new ball smell.
As soon as I bounced the balls on the ground, I could feel they were anything but new.
The balls gave the feeling of being worn out and flat. You could have believed that Djokovic and Nadal had just spent an hour playing with them.
While 7-year-old balls were utterly useless for me, old balls can be used by beginners.
As the balls bounce slower and lower, it is easier for players to react to them. It has a similar effect to the ITF play and stays balls.
These balls are specifically designed to bounce at a slower pace. Whilst they are primarily aimed at children, they can be useful for beginner adults as well.
How Long Does An Unopened Tennis Ball Can Last?
There is no concrete answer for how long a can of unopened balls will last. This is because some cans will leak more air than others.
Different brands of balls may have different lifespans as well.
It’s not something manufacturers investigate or advertise.
This is because they want you to keep buying new balls instead of stockpiling old sets.
It is in their interest that you open the set as soon as possible. This way, the balls will degrade quicker, and you’ll need to buy more.
Two years is a rough guide for when balls start to have a noticeable difference.
At this point, the balls begin to feel the effect of microleakage. However, it is not as though the day the balls become two years old that they start to bounce less.
I’ve never come across a can with an estimated expiry date on it. However, some tennis ball tins will have code on the bottom.
If you really wanted to do some research, you could probably find out when the balls were manufactured by using this.
Most of the time, the only information written on the can itself will be the type of ball and company information.
The company information will be things like the registered address and anything related to the trademark.
Even if the balls may be bad for most players after two years, you will likely be able to find other uses if you’re creative.
I know many people who are into arts and crafts who have made all sorts of things out of old tennis balls.
Will Ambient Temperature Affect Shelf Life Of The Sealed Can?
If you’ve read my article on whether you can store tennis equipment in the car, you will already know this.
Both extreme heat and cold harm tennis balls. Does this apply if they are sealed and unopened?
Even if they are not as vulnerable as tins that are already opened, there is still an increased risk if left in extreme temperatures.
If micro leaks can let tiny amounts of air out, they can also leave the balls exposed to the elements too.
Tennis ball cans are usually made from one of two materials. These are plastic (the same used to make water bottles) or metal.
A famous example of a ball that comes in a metal container is the Slazenger Wimbledon ball.
When evaluating how they will react to extreme temperatures, it is important to consider what material the can is made of.
Plastic is a weaker material than metal. From this, it can be assumed that tennis balls stored in metal cans will hold up better than plastic.
It is unlikely you will notice much difference if the can is still sealed.
If you are cautious, the best place to store them is indoors at room temperature.
Also read: Do Unused Tennis Strings Go Bad?
I remember once there was a local store that had a big sale on tennis ball cans. But, of course, this shop wasn’t a tennis retailer, so I am naturally more cautious.
What I did to check that pressure hadn’t escaped was to squeeze the can.
When you squeeze the can and it changes shape, you know there has been a leak of air.
If it doesn’t change shape, the balls are as good as new.
What is the oldest set of tennis balls you’ve ever played with?