Few things are more frustrating than an aerosol can running out of gas. Unfortunately, though, it’s not an uncommon problem.

So, why do aerosol cans run low on pressure when there’s still plenty of product left in the can?

There could be several factors, starting with the most likely…


Aerosol cans typically use one of two propellants: Butane or CO2.

Butane is generally cheaper; however, because it compresses as a liquid, there’s no way of knowing how much of the can’s contents is propellant (butane) and how much is the actual product.

Put another way: Although the can may say 500 ml, in some cases, up to 40% (200 ml) of the aerosol’s contents may be butane – which is typically cheaper than the active ingredient.

CO2, on the other hand, is significantly safer than butane, but it’s also a far more reliable way to guarantee value and accurately determine the product’s contents.

“This is why it’s vital to shake the aerosol

every time you use it”

In Q20’s case, a minimum of 95% of the aerosol’s contents is oil, while only a small percentage is CO2.

The downside, however, is that CO2 easily separates from oil, and when it does, there’s a good chance more gas (than oil) will escape when the can is used.

This is why it’s vital to shake the aerosol every time you use it, even if the can has only stood for a few minutes.

Shake well before use. Even if the can has only stood for a few minutes.

Of course, the worst thing to do is use an aerosol – without shaking – that has stood for an extended period. Doing so is guaranteed to dispense more CO2 than the active ingredient and will undoubtedly lead to the aerosol running low on gas long before the can is empty.


Due to the internal valve system, most multipurpose oils are designed to operate upright or upside down. Ideally, they should not be used at an angle as this increases the chance of gas escaping at a higher rate than the product itself.


A far less common aerosol problem is associated with rust forming around the aerosol’s seams. Over time, tiny holes invisible to the naked eye can develop within the corrosion and cause a slow pressure leak.


The manufacturing quality may affect the long-term pressure of any aerosol product. Typically speaking, most aerosol cans are manufactured by a 3rd-party supplier, and if the quality standards are low, there may be sealing issues around the seams of the can.

Fortunately, with more than 70 years of experience in aerosol solutions, Q20 routinely checks all our aerosol products using an industry-recognised “bath test”. 

However, in most cases, if an aerosol does run out of gas before the can is empty it’s because of insufficient shaking between uses.

Unfortunately, a common “fix” used by some market participants is to decrease the oil in the can relative to the gas. Which is not strictly ethical.

We’d much rather oversupply the active ingredient and suggest customers “Shake it like a Polaroid picture”.

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