Portuguese Prepper
Mylar Bags & Oxygen Absorbers: The DIY Food Storage Guide
If you leave rice, beans, or pasta in their original grocery store packaging, they will spoil within 12 to 18 months.
Plastic packaging is permeable; it allows microscopic amounts of air and moisture to pass through, causing oxidation and stale food.
To achieve a 20 to 30-year shelf life at home, you must create a true barrier. This requires three things: Mylar bags (to block light and air), Oxygen Absorbers (to remove internal oxygen), and a Heat Seal (to close the system).
Mylar is metalized polyester; it blocks 100% of light and gas.
Oxygen Absorbers prevent bug growth and oxidation.
Thicker is better: Look for 5 mil to 7 mil thickness.
Why Oxygen Absorbers (Not Desiccants)?
Many beginners confuse Oxygen Absorbers (iron powder) with Desiccants (silica gel). For long-term food storage, you need Oxygen Absorbers.
By removing the oxygen, you kill any insect eggs naturally present in grains and prevent the chemical breakdown of the food.
Note: An oxygen absorber will not turn your bag into a hard “brick” instantly. It only removes the 21% of air that is oxygen. The remaining nitrogen stays, so some air space is normal.
Sizing Guide: What to Buy
You need to match the CC (cubic centimeters) rating of the absorber to the size of your bag. Using too little will result in spoilage.
- 1 Gallon Bag: Requires 300cc to 500cc.
- 5 Gallon Bag: Requires 2000cc to 2500cc.
Best Bundles for Beginners
The Heat Seal Requirement
The “ziplock” strip on some Mylar bags is for temporary use only. For long-term storage, you must heat seal the top edge.
You can use a dedicated impulse sealer, a standard clothes iron (on the wool setting), or even a hair straightener. If you don’t melt the layers together, air will leak in.
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