Thursday, January 24, 2019

Storing fats and oils

The fact that oils and fats go rancid in storage struck a nerve with some of my readers.

While prepping for the story I ran into a few facts that I found interesting.

The stabilized (*) HOCAN (High Oleic Canola Oil) in PET bottles was estimated to have a shelf life at ambient temperature of 6.8 years, while oil stored in LDPE bottles had an estimated shelf life of only 2.7 years. The estimated shelf life of HOSUN (High Oleic Sunflower Oil) at room temperature in PET is 2.6 years and in LDPE is 0.88 years.  Source
*1,000 ppm for ascorbyl palmitate, 200 ppm for tertiary butyl hydroquinone (TBHQ), and 200 ppm for mixed tocopherol

Using the same criteria, most vegetable oils have a shelf life of six months from date of manufacture.

Oxygen permeability rates (Oxygen. (g 25μ/m2/24h))

Low Density Polyethylene...8500
Polyvinylidene Dichloride....2

Polyvinylidene Dichloride film can be purchased on eBay if you want to use it to use it as an oxygen barrier between the LDPE cap of most bottles and the glass bottle. Saran Wrap in the US used to be polyvinylidene dicholoride but it is now polyethylene. Wrap sold under the brand name of Saran in Japan is still polyvinylidene dichloride.

Larger bottles have less surface area per unit volume so have better shelf life.

Lower temperature is favorable for longer shelf life.

Darkness is favorable for longer shelf life.

The largest, easy-to-acquire, brown glass bottles are the 40 ounce bottles that hold beer and malt liquor.

Oils that are low in the components that go rancid are Olive Oil, partially hydrogenated anything, peanut oil, tropical oils and some of the high oleic oils. The high oleic oils are currently expensive but production is ramping up as customers shy away from trans-fats.

The price spread between high oleic canola oil and "regular" vegetable oil is about $20 a gallon for HO canola and $8 a gallon for regular.

The fact that peanut oil is a very desirable oil for storage and only costs $11/gallon needs to be weighed against the possibility that one of your people might have a very severe, potentially fatal allergy to peanuts.

Your mileage may vary.


  1. I usually buy olive oil in two /three liter packs and rotate four sets on the shelf of my unheated dry storage shed. Never had any go bad and my cardiologist is happy with my choice.
    (Of course I don't tell him about the home rendered lard I Also store.) We do live 250 miles from city shopping so stocking up is proof against ordinary problems like avalanch blocked roads, earth quakes and plain bad weather here in rural Alaska.

  2. Pemmican would maybe be a good store for emergencies.

    If properly prepared, it'll last for a *long* time if vacuum packed and frozen, and when things go bad, it should last for a year or two after taken out of the freezer.

    That said, I haven't made it or even tasted it, and can't vouch for its longevity.

  3. How would food safe paint cans work for oil storage? I actually have a few cans they were going to throw away at work and let me keep, but I haven't done anything with them yet

    1. I don't know. Wish I had more to share but I don't know.

  4. Bought a device that extracts oil from sun flower seeds. Bet I should pull that sucker out, buy a bag of sun flower seeds (50#) and see how that works. Heard a statistic that it takes an acre of sun flowers to supply a family for a year. I assume that means you only use sunflower oil. You burn that material left over.

  5. Looking over the cans, they hold a gallon but I'm afraid you would spill a lot of oil every time you popped the lid off. On the other hand, the internal height is 7 inches and the internal diameter is 6 3/8 inches. If you transfer your oil into plastic container(s) that fit inside the can then also put a Hot Hand in the can, that would cause the can to seal, deplete the oxygen so it can't penetrate the plastic bottles and outside oxygen can't penetrate the metal can. Now this would work with an ordinary metal paint can. Since the oil would never contact the can, the can would no longer need to be food safe.


Readers who are willing to comment make this a better blog. Civil dialog is a valuable thing.