Why Does My Vape Cartridge Oil Turn Dark Brown

Have you ever had the cannabis oil in your vape cartridge turn dark brown? If so, do you know why that happened and what it means? Can cannabis oil go bad? In this article I will address these questions, will discuss how your vape cartridge works, and will provide tips on how to maintain your cartridge to increase its longevity.

What is Inside Your Cannabis Vape Cartridge?

Contained within the glass or plastic tube in your vape cartridge is approximately one gram of cannabis concentrate oil full of cannabinoids and terpenes. At the bottom of the cartridge, there is a metal plate that is heated by the battery located at one end of the vape pen. The oil is vaporized and inhaled through the mouthpiece.

Flower can lose its potency fairly quickly over time as it dries out, leading to the degradation of terpenes. While vape cartridges have a longer shelf-life, they do not last forever.

How The Oil in Cartridges Changes Over Time

In case you weren’t aware, your cannabis oil is made up of lipids and molecules in complex chains whose bonds are not terribly strong. The heating of the oil on a regular basis results in the breakdown of these molecular bonds. It is important to note that THC molecules in cannabis will degrade into CBN no matter what delivery method you use. For those unfamiliar with CBN, when cannabis ages, the THC breaks down into CBN which has only mild psychotropic effects. The rate of THC degradation in your vape cartridge depends on the following:

Heat Inside and Outside the Cartridge

Exposure to high temperatures over a period of time will increase the degradation of both the oil and the THC. Not only does the heat come from within the cartridge, it also comes from outside the cartridge. Because vape manufacturers choose to make their cartridges as cheaply as possible, this means that the tubes are not very effective at keeping out the heat from external sources. These include:

  • Exposure to high temperature in a car or any other hot enclosure
  • Body heat transmitted through a pocket of the user
  • High temperature on a hot day
  • Exposure to Light

Exposure to light, especially sunlight, will quickly age your THC into CBN which does have some medicinal benefits.

3 Ways to Tell If A Vape Cartridge Is Bad

While vaping an old cartridge doesn’t actually carry any serious health risks, here are the ways to tell if your cartridge is bad:

  1. Check the Clarity and Viscosity of the Oil

The oil in the cartridge should be as clear and viscous as when you bought it; uniformly light yellow to amber in color and fairly transparent. If the liquid is discolored or has turned brown, the cartridge should be thrown away. If the oil is thick, full of sludge, cloudy or you can see crystals growing from the sides, it is time to throw it away.

  • Please note that in doing my research for this article, I found several posts in which consumers disagreed with the above analysis. Here is their explanation for a darkening of cannabis oil in vape cartridges:
    • Because high-quality vape oils are free of additives and preservatives, the ingredients that they contain are responsible for changes in the color of the oil over time.
    • Every time you vape, the oil is subject to the application of heat and oxygen which leads to the oxidation process. This causes a change in the color of the oil. The older the vape oil, the more likely it has gone through the oxidation process and the darker the oil. This does not mean that your vape oil cartridge is bad and needs to be discarded.
  1. Taste Test

Even if there is little noticeable change in the oil, the taste test will be a giveaway. If the vapor tastes bitter or sour, it should be tossed away. It may also make you cough much more, make you tired or give you a headache.

  1. Loss of Potency

You will notice that there is a reduction in the potency of your vape oil.

Ways to Increase the Longevity of Your Vape Cartridge

By purchasing high-quality cartridges and storing them properly, they can last up to a year without loss of potency. It is highly recommended that you purchase vape cartridges from a trusted source such as your local medical cannabis dispensary. Make sure that they include the following information:

  • Lab Reports
  • List of Ingredients
  • Place of Origin

Remove The Cartridge From the Battery

Even when you are not using the vape cartridge, as long as the metal plate maintains contact with the battery, there will be a small amount of power generated which will continue to heat the oil. That will ultimately damage the integrity of the cannabinoids and terpenes. By unscrewing the cartridge from the battery and storing it upright, it will also prevent oil leakage and potential damage to the cartridge from breakage.

  • Store Your Cartridge in A Cool, Dry Place

When THC molecules are exposed to temperatures above 70° F, they start to degrade into CBN. Consider buying a small protective case to protect it from heat if you tend to carry the cartridge in your pocket. At home, if it is not in a protective case, store it in a cool, dry place like a drawer. Avoid placing it on a windowsill!

  • Buy A Hash Oil Syringe

Another way to preserve the oil in your vape cartridges is to buy a hash oil syringe and fill your own cartridges. You can buy them at many dispensaries. Obviously, you need to store the oil in a cool, dry place until needed.

Happy Vaping!


potguide.com, Do Vape Cartridges Go Bad? Paul Barach, Nov. 12, 2020

vapebright.com, Why is My CBD Vape Oil Turning Dark Brown or Black, Aug. 30, 2019