EVOO Chemistry: Peroxides

When we talk about peroxides in the context of olive oil, we are not talking about the hydrogen peroxide that can be found in your medicine cabinet. We are talking about compounds that result from the oil oxidizing due to improper storage and handling. 

Storing your EVOO in a way that limits its exposure to oxidizing agents is crucial to preserving its flavour and desirable chemistry. The three biggest factors that lead to an oil going rancid are heat, light, and oxygen. These factors accelerate the oxidizing of the oil's constituents, which results in peroxide formation.

Light, Heat, and Oxygen

These three factors are the greatest enemies of fresh EVOO. Excessive exposure to any of them can lead to the fatty acids of the oil's triglycerides (the main component of any oil) oxidizing at a far greater rate than they normally would. This reaction leads to accelerated spoilage of the oil and that distinctive rancid oil smell that indicates the oil is unfit for use. 

Fortunately, there are measures you can take to help limit how often your EVOO is exposed to these oxidation factors. Proper storage is the easiest thing you can do to help extend the life and flavour of your extra virgin olive oil. 

Here are the top tips for how to store your EVOO:

• Keep the bottle firmly sealed with a cork or pouring spout
• Ensure the bottle is stored away from sources of heat like an oven
• Keep the bottle in a dark space such as a pantry or cupboard

Consuming your EVOO quickly is always best, as its oil chemistry and flavour are at their peak in freshly-crushed oil. But for when you do keep a bottle around for a few months, storing it in a way that minimizes those undesirable oxidation byproducts is key. Check out our blog on Expiry Dates to find out how long EVOO can last with proper storage; your wallet and taste buds will thank you!