does emulsion paint go off

Does Emulsion Paint Go Off? (and how to prevent foul-smelling paint) – UK DIY Guide

Yes, emulsion paint does go off. But how do you know it’s gone off and what’s the best way to extend its shelf life?

In this guide, we’ll address these common questions and provide some top storage tips that will maximise the lifespan of your unfinished tins of emulsion paint.


How Long Does Emulsion Paint Last Before it Goes Off?

The time frame will vary, but typically once you’ve opened a tin of paint, you’ll have about six months before it starts to go off. However, this largely depends on where you’re storing your emulsion paint. For example, temperature, humidity and sunlight all play a significant role. 

Some manufacturers state that unopened and adequately stored emulsion paint has a shelf life of up to 10 years!  

How do I know if my Emulsion Paint has Gone Off?

There are a few ways to tell if your emulsion has gone off, from the smell (old paint smells horrendous!) to the shape of the tin.  

Paint Smell

The smell is the biggest giveaway that your emulsion has gone off. Imagine a scent that’s a combination of sour milk and wet dog. That’s the nasty smell of emulsion that’s gone off! 

Paint Container

One of the main reasons paint goes off is bacteria getting inside the tin – eating away at the emulsion paint and giving off gasses, which ultimately causes the can to swell. 

As well as a swollen tin, the lid bulges outwards. You’ll know immediately that your emulsion is off if you see this. 

If your tin looks normal, take a closer look and check for any rust. Take a good look at the underside of the lid. If there’s any rust, it’s because air has managed to get inside. Remember, don’t use paint from a rusty tin; there could be metal flakes in the paint.  

Consistency of Paint

lumpy emulsion paint that has gone off
Source: Vintage Soul Designs

If the smell isn’t too bad and the tin isn’t bulging, another way to tell if your paint is off is from its consistency. I.e. the emulsion might look watery and lumpy; this happens when the pigment separates from the paint compounds. 

If your emulsion is off, it will have separated, begun to dry out and might have a runny consistency. There might also be mould or mildew on the surface – don’t use paint that has any mould settled on it! 

Generally, paint separates a little whilst not being used. So, try stirring the emulsion; if it mixes well and stays together for 15 minutes, the emulsion should be fine. In contrast, an emulsion paint that’s gone off won’t mix well. If it does, it quickly separates again.  

Test Paint

If you’re still unsure, the best way to tell is by testing a small paint sample. Using scrap cardboard or old paper, paint a 10cm strip. If the emulsion goes on smooth, then it’s okay. If the emulsion paint is lumpy or has bits of debris floating inside, don’t use it.  

Still Unsure?

If you’re still unsure what to look for, please watch the video below for a visual guide.

YouTube player

The Best Way to Store Emulsion Paint

If you’re looking to maximise the shelf life of your emulsion paint, there are a few things you can do:

  • Store the paint in a cool and dry area, away from direct sunlight or heat sources such as radiators.
  • If possible, store your paint tins on their side. Keeping paint this way helps prevent clumping issues.
  • Firmly close lids after use (especially if storing for long periods). Otherwise, air gets in, allowing bacteria to eat away at the paint. 
  • When buying paint, check the tin to ensure it isn’t damaged.

Does Emulsion Paint Go Off? – Final Thoughts

You now know the tell-tale signs of gone-off emulsion paint and the best methods to maximise its shelf life.

Use this newfound knowledge to prevent unnecessary waste and save money. The planet and your bank balance will thank you!

Check out our emulsion paint buying guide to find the best emulsion paint in the UK.