Written by Plant Therapy January 17th 2019

Breaking It Down

One question we see often here at Plant Therapy: Do essential oils expire?

So let’s talk about essential oil expiration and shelf life! This is a question that we see a lot. There are a lot of misconceptions stemming from the significant increase in popularity essential oils have gotten over the past several years and it’s time we really dive in and take a deeper look.

Let’s start with the misconception itself. At some point in your essential oil journey, you’ve probably heard someone say, “Well, if the oil is pure it does not expire.” You may have also heard that essential oils don’t grow mold, mildew, or yeast. All these things are true, but we’re not done there.

So, Do Essential Oils Expire?

Essential oils do not expire. They do not grow mold. They also do not grow mildew or even yeast. The false hope these facts cause is that essential oils will last forever and that they have an indefinite shelf life. This is very far from the truth.

The Science

Oxidation. Such a simple, yet complicated word.  Oxidation is the process or result of oxidizing or being oxidized. Oxidized means to undergo or cause to undergo a reaction in which electrons are lost to another species. But wouldn’t that result in an oil becoming something else? Bingo. That’s exactly what it means, and why essential oils most definitely have a shelf life.

When you look at essential oil safety, you’re really sitting down and looking at the chemical constituents that make up an oil, not really the oil itself. You look at the different constituents that an oil is composed of, the levels of each constituent, and the safety information attributed to each constituent. This is why GC/MS reports are so important because they tell you what exactly your oil is composed of and how much.

Throw oxidation back into the mix. The constituents that make up your essential oil start to break down and turn into new constituents altogether. What do they turn into exactly? Nobody knows. It depends on the constituent, the amount of time it’s been oxidizing, etc. The only way to tell for certain is to retest the oil.

Breaking it Down

While essential oils don’t “go bad” the way food does, they do change over time. And because they change over time, and we don’t know what’s in them, the safety of an oil can’t be fully determined. But the good news is, there are things you can do to slow down the rate of oxidation and extend the “life” of your oil but you need to know what contributes to an essential oil’s oxidation process.

Oxygen, heat, and light. Three everyday forces that greatly impact the shelf life of essential oils. Oxygen is probably the biggest contributing factor to oxidation since oxidation can’t happen without oxygen. Heat and light also contribute to oxidation, but for different reasons. Reasons we are not going to dive into, because, well… nobody wants this to turn into a full-blown chemistry lesson.

Oxygen

Oxygen exposure can be reduced by ensuring you recap your essential oil bottles tightly and quickly. Don’t let your bottles sit out on the counter open for too long. This allows oxygen to penetrate the bottle and increase the rate of oxidation. A pro-tip to consider is decanting your oils into smaller bottles as-needed. If you buy a 10ml bottle of essential oil and use 5ml or more, consider pouring the remaining oil into a smaller sized bottle.

Heat

Heat exposure can be reduced by keeping your essential oils in a cool place, like a fridge. According to Robert Tisserand, the ideal temperature for essential oils is between 35 and 38 degrees. There are some things to consider, though. Because essential oils are so powerful and aromatic, they do have the ability to alter the taste of the food and beverages stored with them in the fridge. You can help reduce these effects by storing them in separate containers in the fridge. Or, you could do as many do and buy a whole separate fridge.

Light

Light. Naturally, the way to reduce light exposure is to keep essential oils stored in a dark-colored bottle and keep them in a dark, cool place. If you can’t afford a fridge for your essential oils, and you don’t have the room to store in them in your regular fridge, consider storing them in another dark and cool place like a cabinet.

In Summary

There is a whole lot of science and chemistry behind essential oils and their respective constituents. The problem is that while the oil may not go “bad” – it doesn’t stay the oil you know and love forever. It will begin to change and break down. And while there may not be an exact science behind the “shelf life” of an oil, there is a pretty good idea on how long an oil should last if stored properly.

You can check out our recommended shelf life chart here.

So now the question is, when does the shelf life start?

We cannot speak for every company’s essential oils, but Plant Therapy’s essential oils are stored in a barrel topped with a nitrogen barrier that helps keep oxygen out. This prevents oxidation while it waits for bottling. Once the oil has been bottled, we have a strict forecasting structure to prevent oils from sitting on the shelf for prolonged periods of time. Because we have these procedures in place, it gives us confidence that the shelf life of your oil will start as soon as you receive it.

Tips For Getting The Most Out Of Your Oils

• Colored bottles help keep the oil out of direct sunlight.
• Keep your bottle capped tightly.
• Keep them cool! The ideal temperature is 35-38 degrees Fahrenheit, the temperature of most refrigerators. Keep the oils in a container (like a wooden box or plastic bag) unless you want your food to start tasting like your oils!
• Some oils become thicker as they cool. This is totally normal. Just warm the bottle up in your hands for a moment to return it to a more liquid state.
• You can tell if your oil has oxidized if it does not smell as fresh as it did originally.
• Citrus oils can go cloudy. If this happens, let the sediment settle to the bottom of the bottle and use a clean pipette to transfer the good oil into a clean bottle.
• Using a personal inhaler? Refresh it about every 3 to 4 months, since inhalers get frequent exposure to the air.