Food ranks highly in anyone’s prepping activities and while I have rotating food stocks, I wanted to look at some longer term storage for raw ingredients as a further backstop should the SHTF.  I decided to try some Mylar bags with oxygen absorbers since they have a reputation for allowing storage of food for a number of years.


What is Mylar?

Mylar is a trademark of Dupont and was developed in the 1950’s.  It is a range of plastic sheet products made from the resin Polyethylene Terephthalate (PET) and has a number of useful properties.  Whilst it is light, thin and flexible it also has durability and strength.  With the application of heat it can be given an airtight seal.


What are Oxygen Absorbers?

Oxygen absorbers are small packets of a powder comprising iron and sodium chloride.  When exposed to air, the iron ‘rusts’, using the sodium chloride as a catalyst, absorbing the oxygen from the air.  Since it is oxygen that helps food products to deteriorate, the removal of the oxygen, down to just 0.1% when done correctly, results in a much longer term environment in which to maintain food. Oxygen absorbers are sized to remove a certain volume of oxygen therefore  the bag and oxygen are paired up for compatible size and capacity.


How to use Mylar Bags & Oxygen Absorbers

Get Everything Ready

First of all, I ordered a pack (eBay) of matched ‘1 Gallon’ Mylar bags with matched 300cc oxygen absorbers.  Using this size of bag you should be able to store around 4Kg of flour or 2Kg sof pasta.  In opted for these stronger 7mil bags over the cheaper 3-4mil bags available.

The next requirement is clearly the food you want to store.  I purchased a range including flour, pasta, red kidney beans, chickpeas, rice and sugar as you can see in the photo below:

There is an important note here to remember.  Do not open the sealed pack of oxygen absorbers before you have your Mylar bags full and ready to seal.  Once opened you only have about 15 minutes to work with the absorbers before they have already absorbed too much oxygen to be useful!

Fill the Bags

With a permanent marker, the contents,the best before date from the packet and the date they were sealed were written on each bag. I distributed the food into 10 mylar bags and weighed the contents to see how much each one would hold. Once the bags were weighed, I added the weight to the marking as well.


Mylar Bag - Markings


I ended up with the following bags:

  1.   Long grain rice – 3Kg
  2.   Long grain rice – 3Kg
  3.   Pasta – 2Kg
  4.   Pasta – 2Kg
  5.   Pasta – 2Kg
  6.   Red kidney beans – 2Kg
  7.   Red kidney beans – 2Kg
  8.   Plain flour – 3Kg
  9.   Strong white flour – 3Kg
  10.   Sugar – 3Kg

Mylar Bags - Filled

Once the bags were filled, weighed and marked, it was time to add the oxygen absorbers, one to each bag.


Mylar Bag - Oxygen Absorber

Seal the Bags

Now, they were ready to seal.  You can use a normal domestic iron with the steam settings turned off, but I purchased a cheap pair of ceramic hair straighteners which make a slightly better job and are easier to use as you don’t need to lie the bag down.



Using the straighteners, you simply seal along the top edge of the bag.  Make sure you seal the top 25mm of the bag.  Avoid having wrinkles in the Mylar wherever possible as they increase the chances of breaching the seal.

Storing the Bags

I packed the sealed bags into two 35L ‘Really Useful’ boxes. As a result, they will be stored securely and protected them from any potential rodent or insect activity.


Mylar bags - Sealed & Stored

The oxygen absorbers will remove the oxygen from the top of the bag.  Don’t expect the bag to shrink tightly as this is not a vacuum seal.  The oxygen absorber only removes the oxygen is from the air in the bag.  Because there is only around 21% oxygen in air, the bulk of air being nitrogen which will be remain in the bag.

I plan to fill the gaps in the boxes with smaller mylar bags containing herbs and spices. This will make use of the available space in the storage boxes and  widen the range of flavours available.


Final Thoughts

I have seen no hard facts regarding how long food will keep in sealed mylar bags with oxygen absorbers.  With a quality bag, a good seal and storage in a cool, dark environment, it is certainly years, and possibly decades depending upon the sources you read.  My plan is to use it as another element of my food prepping alongside standard rotated stocks. I will check the bags in six months and if they look like they are doing the job I will store another batch.