Tips For Storing Oils To Prevent Rancidity.

If you think storing your oils in the cupboard is best way, you maybe dead wrong. Many people have been storing their cooking oils or products containing oil or fats under bad condition. Oils need to be stored at the right temperature or under the right conditions to maintain its quality. 

Storing Oils In The Refrigerator Can Prevent Rancidity.

cooking oil

It’s Summer time. Today is 95 ºF in New York City. The Apartment is hot and very humid. Seems like the entire summer will be sticky hot and COVID-19 does not make it any more fun. You have 2 gallons or 2 liters of vegetable oils stored in your pantry that you purchased on sale a few months ago. They have been sitting there for months in a heat bath.This constant exposure to high temperatures can affect the quality of your oils.

Most  of us store our cooking oils at room temperature in our cupboard or pantries. Temperatures in your cupboards can get very high during very humid days. If you cook often, especially during the warmer months, heat generated from the stove can lead to blazing hot temperatures inside your food storage units.

Exposure of oils to high temperature or heat over time changes the chemical composition of oils and can cause them oxidize and go bad.

Even If your home or apartment has central air, one cannot be sure that you oils can be protected from a heat stroke. Then again, who runs their AC all day? I would highly recommend storing your oils in the refrigerator.

Storing Your oils or products containing oils in the refrigerator can prevent rancidity and increase its shelf life. In this blog, I will be sharing with you some tips on how to protect your oils from going rancid.

cooking oils

Many manufacturers will instruct you to store your oils in a cool dark place such as your cupboard. Great! 

But many companies may not factor in that internal temperatures of your cupboard or pantry over extended periods, especially during the warmer seasons, can turn your oils rancid or negatively affect the quality of your oils.

Refined vs. Unrefined Oils.

Look at the labels on the container of your oils. They will either be labeled as refined  or unrefined.
Refined Oils have been processed so much that they loose some of their natural taste and smell and most importantly, some of their nutritive value. These oils usually last around 6 -12 months if they are store in a cool, dark place.
Unrefined Oils on the other hand, are in their more natural state and have more nutritive values. These kinds of oils, if stored in a cool, dark cupboard can last up to 6 months. These oils are best stored in the refrigerator.
cooking oils
cooking oil

Store Your Supplements with Oils In The Refrigerator.

Supplements such as Cod Liver Oils, Vitamin D capsules, Fish Oils, Garlic oils or fat soluble vitamin supplements: Vitamin A, D, E and K can also go rancid. These or other supplements that contain oils should be stored in the refrigerator for longer lasting freshness and preservation of their nutritive value. They may get a bit cloudy, but this is fine. 

chia seeds

 Nuts and Seeds Contain Oils/Fats.

Yes, nuts and seeds such as Flax Seeds, Chia Seeds or Chia Powder, Almonds, Cashews or Peanuts all contains oils. They too, over time,  can become rancid if not stored under the right conditions. 

What Foods Can Get Rancid?

  • Baby Formula
  • Milk Powders
  • Cereals
  • Salad Dressings
  • Peanut or Nut Butters
  • Chips: Corn or Potato Chips
  • Vegetable Oils: Canola Oil
  • Sesame oils, peanut oils or other nut oils.
  • Olive Oil
  • Coconut Oil

What Factors Lead To Oil Rancidity?

  • High Temperatures
  • Direct Sunlight
  • Oxygen Exposure
  • Improper Storage

Why Does Rancid Oils Matter?

What Are The Health Effects Of Rancid Oils or Fats?

During the process of rancidity, oxygen interacts with the chemical structures of the oil and changes its natural structure. This change in structure can consequently lead to a change in odor, color, consistency, nutritive value, and can have harmful effects on your health.

Gastrointestinal Issues

Eating small amounts of fats or oils that have gone rancid can lead to Gastrointestinal discomfort such as bloating, diarrhea, vomiting, and nausea. 

More Serious Complications

However, consuming fats that have become rancid, over longer periods can lead to more serious health complications such as intestinal bleeding, severe intestinal or digestive issues, skin issues, hair loss and inflammation.

Biochemistry of Fats/Oils

Manisha, in his article Rancidity Of Foods…  provides you with details about the biochemistry of fats and rancidity.

Tips For Storing Oils and Preventing Rancidity


Buy Smaller

If you do not use oil a lot for cooking, then buying gallons of oils on sale or in bulk at BJs may not be the best option. Buying smaller containers of oils can save you money in the long term.


Storage Container Matters

Buy Oils in containers that are either dark plastic or dark glass. This blocks out sunlight that can potentially damage the chemical structure of the oils. If your oils are in a clear containers, pour into darker containers for best storage.


Proper Storage is Key

Most vegetable oils, if stored properly, can last at least 1 year. Once oils are purchased, store in a cool, dark, dry place such as your pantry or cupboard. 

During the warmer months, store oils such as vegetable oils, or olive oils in your refrigerator.

Never store your oils in the cupboards directly above or near the stove.  

Never Store your oil on the stove top. 

Do not leave container with oils uncovered. This will expose them to oxygen and lead to oxygen rancidity. 


Store Oil Based Supplements in Refrigerator

Supplements or gel capsules such as Fish Oils should be stored in the refrigerator as soon as the seal is broken to avoid rancidity.


Be Careful of Bulk Purchases

Avoid Buying seeds, nuts, or grounded seed/nut from the bulk bin as would observe in many Whole Foods Market. 

No one can tell how long these foods have been sitting there and how long they have been exposed to the 3 harmful contributors of rancidity: heat, light and oxygen.


Check Expiration Dates/Use labels

Not because a food product is not expired does not mean it is fresh. Adapt the habit of checking expiration dates of products in the supermarkets. Use a marker to label the date that the oil was opened.

Check for Signs of Rancidity

Periodically check for signs of rancidity: (a) oils that have become darker in color, (b) very viscous and does not run as fluid, has a foul smell, or (c) have very sticky residue near or around the cover of container.

If you observe these signs of rancidity, discard of oil in garbage; never down the drain.

Did You Enjoy the blog? I would love to know what you think. If so, see my other posts. Be sure to leave a comment. 

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35 thoughts on “Tips For Storing Oils To Prevent Rancidity.”

  1. Amazing and useful article, many people don’t know that poor storage of oil can cause serious diseases, the article is very well explained. Congratulations

  2. This is some great information. Never knew oils can go rancid. Will definitely be giving thought when i store my oils and nuts.

  3. Wow, I should really throw out my expired sesame oil! I didn’t know there were health risks involved. What a great article, thanks for posting!

  4. Oh my goodness… this is excellent information. And now I need to go clean out my cabinet and put some things in the fridge! Thank you for the inspiration.

  5. Thank you so much for these Tips For Storing Oils To Prevent Rancidity. I never really though of this before. I definitely wouldn’t think chips could possibly turn rancid because of the oils in them. So interesting, and a very thorough article!

  6. This is such a helpful article, I’m always concerned about food going rancid. I’m definitely bookmarking this for future reference. Thank you for sharing!

  7. This is a great post. I never knew storing oil in the correct place can make so much difference. I guess I shop less or consume oil quickly, so I never thought about its shelf life. Thank you for sharing informative and helpful post.

  8. Great post and I learned so much about the different types of oil and how to store them properly. I knew that storing the different kinds of oils would influence their quality, but you showed excellent examples and reasons as to why. Thank you

  9. Such great information! I had no idea about storing some vitamin supplements in the refrigerator. I’ve been taking Vitamin D for years and will now refrigerate. Learned a lot here. Thank you!

  10. Wow this is super interesting!! I had no idea this was a thing. To be honest though I only buy olive oil and we share it and go through it I would say once a month I buy a new bottle. Very good information to consider when buying oils thanks for sharing!!

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