If you’ve found some old tubes paint in your studio, you may wonder “does acrylic paint go bad?” The answer is yes, it can go bad in a variety of ways. In this article I describe how to tell if it’s gone bad and how to store acrylic paint so that it lasts years.
From the research that I’ve conducted, most manufacturers say their paint is good for at least 5 to 7 years. Acrylic paint can go bad in a number of ways; it dries in the tube, becomes chunky, develops mold, or gives off unpleasant odors. The individual components can begin to separate, but that alone doesn’t necessarily mean it’s bad.
Shelf Life of Acrylic Paint
I searched the websites of the most popular brands of acrylic paint, and only a few of them specified a shelf life in years. Golden Paints state that their acrylics can last “many, many years” if well stored. I think this is the best answer because it’s impossible to control how artists store their paints. Golden qualifies their statement with the phrase “well stored paints” which is the best case scenario.
|5 -7 Years
|Winsor & Newton
|W&N YouTube Video
Signs That Acrylic Paint Has Gone Bad
The Paint Dries out It the Tube
There are a number of indicators that the paint has gone bad. The first and most obvious example is the paint dries up in the tube. Below is a photograph of the first tube of professional acrylic paint that I bought in 1989. It’s totally solid. It doesn’t matter how well you put the cap on, it will eventually harden in the tube with enough time.
The Paint Develops a Chunky or Lumpy Consistency
The picture below is of an old tube of Grumbacher acrylic paint. Once acrylic paint becomes lumpy, the best thing to do is to replace it. It’s tempting to try and smooth it out by mixing it with a palette knife but I don’t recommend it. If you’re going to spend time making a painting to hang in your home or sell to a collector, why waste your time with inferior art materials? Some part of the paint has changed for the worse. I want my paintings to last as long as possible, so I’m not willing to use subpar materials.
When paint is stored for extended periods, it’s common for it to separate. What I mean by “separation” is the individual components of the paint start to separate from each other. This is similar to how the water in a bottle of salad dressing will separate from the oil.
When this happens with acrylic paint, it doesn’t necessarily mean the paint is bad. One way to tell if it’s gone bad is by the smell. (It’s best not to smell the tube of paint directly, see the section on odor below). If it smells okay then it’s worth trying to mix the paint up. There are a couple of way to mix the paint, but the best way depends upon the type of container the paint is in.
If the paint is in a jar you can use a palette knife or any other clean tool to stir it up. Thinner, fluid acrylics in a bottle can be shaken.
Remixing Separated Paint in a Tube
Tubes of paint can be somewhat challenging to remix. For one, the only way you can tell if the paint is starting to separate is when you squeeze it out on a palette. You’ll notice a puddle of clear liquid, followed by the paint. The problem is that the clear fluid has already been squeezed out of the tube and is on the palette.
One solution is to squeeze out the entire contents of the tube and mix it up with a clean palette knife. After mixing it to a uniform consistency, store it in an airtight container. Another option is to put the cap back on and knead the tube with your fingers. However, you won’t be able to incorporate the clear fluid that’s on the palette.
Mixing the paint by kneading the tube can be messy for a number of reasons. If there are any leaks in the tube, the paint will seep out of them as you squeeze it. The other problem is that squeezing a tube of paint builds up the pressure inside. When you take the cap off, a big blob of paint can the paint can come out of the tube. It’s a good idea to wear gloves and cover your work surface with newspaper before you begin.
I don’t recommend opening tubes of paint and smelling them directly by putting them up to your nose. When paint goes bad it can smell awful. Also, mold is an allergen and can cause reactions. But if the paint has gone bad, you will notice an odor shorty after squeezing it out onto a palette.
Most of the time I don’t notice any odor when I’m painting with acrylics, but it depends upon the brand. The only smell that I associate with acrylic paint is the slight scent of ammonia, which I believe is added to the paint to prevent it from spoiling. It’s a very slight odor, especially in the small quantities that are squeezed out onto an artist’s palette.
If you notice a musty odor or a sour smell, then the paint has probably gone bad. Discard it. Foul smells can be an indication that mold has started to develop and mold isn’t good for your health.
If you open a jar of paint and notice mold on top of it, then replace it. The mold will be more visible with lighter colors than dark colors. But if you’re not sure then you can probably tell by the unpleasant smell. I’ve never seen dark spots in tubes of paint, I think because it’s not in contact with air. It can still develop mold and you should be able to tell by the odor if mold has started to grow.
How to Extend the Shelf Life of Acrylic Paints
The enemies of acrylic paint in storage are; air, extreme temperatures, and contaminants. While most manufacturers claim the shelf life is between 5-7 years, it’s not uncommon to have paint remain good for over 10 years if stored properly. I had acrylic paint remain usable for over 15 years.
Store in an airtight container
Acrylic paint will begin to dry by exposing it to the air and allowing the water to evaporate. Brand new containers of paint should be left sealed until you plan on using them. Once you open a tube or jar of paint, make sure you put the cap back so it forms an airtight seal.
If you let the paint build up on the threads of the tube or jar, then you might not be able to get a good seal which will lead to the paint drying out. Most tubes of paint are made from a type of plastic that dried paint doesn’t stick to very well. If the paint dries on the threads then just simply peel it off.
Another way paint can become exposed to air is through small cracks or openings in the tube itself. Metal tubes can break open along the larger creases. If your paint is in metal tubes, try not to crease the tubes excessively and it shouldn’t leak.
Plastic tubes seem more durable but they have a different problem. The design of some plastic tubes don’t allow the tube to remain compressed after you squeeze some paint out. After you squeeze the tube, the plastic wants to spring back to the original shape, which introduces pockets of air into the tube.
Avoid Storing Acrylic Paints in Extreme Temperatures
Avoid storing acrylic paints in places where the temperature can fluctuate; attics, storage sheds, garages, and in the trunk of your car. Excessive heat can affect the shelf life of acrylic paints.
According to Golden, acrylic paint can survive being frozen, but they don’t recommend it. Ordering acrylics online in the Winter means that your acrylic paints could be sitting on an unheated truck overnight. Also, the package may sit on your porch long enough to freeze. I usually put in an order for paints in the Fall before the temperatures drop. Another option is to use a brand of acrylics that are readily available at the local art supply stores, or the big box craft stores.
Plein air painters shouldn’t leave their acrylics inside of their cars for extended periods. The temperature inside of a parked car can reach temperatures up to 170 degrees F (77 degrees C). In the Winter, temperatures can drop below 0 degrees F (-18 degrees C). These are far from ideal conditions for acrylic paints. You can carry your paints with you in a small backpack instead of leaving them in your car. If you work through tubes of paint rather quickly then how you store them isn’t as important.
Don’t Contaminate Unused Paint
Believe it or not, tap water is a contaminant. Tap water contains microbes and minerals. If you add tap water to a jar of acrylic paint and store it for a few years, it will probably develop mold.
If you want to thin out your paints with water and store them for an extended period, use distilled water. Unlike tap water, distilled water should be free from microbes and minerals. Dipping a wet paint brush into a jar of water could introduce tap water into the paint but I wouldn’t worry about it too much.
Another source of contaminants is foreign matter. Some artists like to add sand or pumice to their paint to give it texture. If you mix either of these materials into a large jar of paint, it’s best to only mix up what you need for the short term because these materials may introduce enough contaminants to create mold growth if stored for extended periods.
I generally don’t worry about mold growth. Most of my paints are in tubes and I don’t store diluted paints for more than a few days while I’m working on a painting.
Acrylic paints can remain usable for years if you store them properly. Extreme temperatures can make your acrylic paint go bad faster so keep them indoors at room temperature. Try to prevent the paint from building up on the threads so that it forms an air tight seal when you put the caps back on. Acrylic paint can survive freezing temperatures but you should avoid it if possible. Tubes of paint are less likely to get contaminated than jars. Watch out for plastic tubes that spring back to their original shape after being squeezed because that introduces air into the tube.
The best way to avoid having your acrylics go bad is to use them up by making a lot of paintings!