What are Mylar Bags?
Mylar or BoPET film was developed by DuPont around 1955 and used by NASA for blankets and long-term supply storage. Kodak also used Mylar as a backing for the photographic film. The bags are made of polyester resin that is laminated to aluminum foil but in its natural form, mylar is a clear material.
They essentially become flexible tin cans for storing food when sealed properly. Mylar bags are reusable as well, making them a great value for the prepper’s pantry. Mylar bags keep a barrier between your food and the environment and the effects of heat, light, moisture, and oxygen. Mylar bags can be sealed with a simple clothes iron and many have optional that make them resealable.
Why Do Preppers Use Mylar Bags?
Mylar bags have been the standard for long term food storage in the prepper world. They are preferred over zip loc bags and even vacuum sealed food saver bags. Mylar bags and oxygen absorbers are a great combination that can take your food storage from years to decades! Dried food products, such as white rice, beans, and oatmeal can be stored from 20 to over 30 years if stored properly. It’s kind of a “set it and forget it” approach due to its high tensile strength and its moisture, light, and gas barrier.
Mylar is the gold standard in long term food storage because it’s:
- Non-porous
- Impervious to gasses
- Reflects light
- Very Flexible
- Durable to a certain point
- Inexpensive and comes in many sizes
- Easy to use and store
How to Choose the Right Mylar Bag
When you decide to take the jump to mylar storage bags, try to get the thickest bag you can afford. Mylar comes in several different thicknesses and it is best to choose a thicker material to keep certain foods such as pasta from poking through.
Here are some common thicknesses of mylar:
- 2.85 mil
- 3.0 mil
- 4.3 mil
- 5.0 mil
Additionally, there are several different sizes of mylar bags. Some of the more common sizes are:
- 1 Quart
- ½ Gallon
- 1 Gallon
- 5 Gallon
The larger the size of the mylar bag the larger the size of the oxygen absorber you will need. Many preppers choose to store a single bulk food inside a 5-gallon bag placed in a bucket. Others like smaller volume bags and store them in buckets or tubs. 5-gallon bags are mainly for bulk food storage, so if you plan to use your long-term food storage more often, the smaller sized would be more convenient.
Here is a general chart for oxygen absorber to mylar bag sizes:
| Mylar Bag Size | Oxygen Absorber Size |
| 1 Quart | 100cc |
| 1 Gallon | 300cc |
| 5 Gallon | 2000cc – 3000cc |
How to Choose the Right Oxygen Absorbers
Along with mylar bags, you will need oxygen absorbers. Oxygen absorbers are added to a mylar bag of dry food before they are sealed to remove oxygen. I recommend that you order higher than suggested oxygen absorber sizes to increase the amount of oxygen removed and increase the shelf life. Further, getting one larger size for all your bags can keep things easier than trying to figure out what size you will need for a certain bag.
How to Use Mylar Bags for Long Term Food Storage
For the steps below, I will be using a one-gallon mylar bag with 300cc oxygen absorber and storing white rice.
What you will need:
- 1 Gallon Mylar Bag
- White Rice
- 300cc Oxygen Absorber
- Clothes Iron
- Straight Edge
- Five Gallon Bucket or Tub (for storing sealed bags and protect them from critters)
- Get your iron hot, the thicker the mylar, the hotter the iron should be. A general guide is medium heat for 3-mil bags, medium high for 4-mil bags and higher for a 5-mil bag.
- Fill your mylar bag with dry food to a few inches below the tear marks leaving room to seal the bag.
- Add the oxygen absorber. It doesn’t matter where you put the absorber but make sure it is not going to interfere with your seal.
- Find a straight edge, a level or 2.4 piece of wood will work just fine. Fold the top of the bag over the straight edge. Make sure the bag is as smooth as possible over the straight edge. This may take some time and practice.
- Double check that you placed your oxygen absorber in the bag. Get as much of the air out as you can then seal the bag across the straight edge by going back and forth with the iron. The seal should take in a few seconds.
- Let the bag seal cool. Squeeze the bag and make sure no air is escaping. You may have a few that do not seal properly in the beginning, getting it just right takes time.
- Be sure to label and date the bag before you store it away.
- Store your freshly sealed food in a five-gallon bucket or a sturdy tub to keep insects and rodents from trying to chew their way in.
- That’s it!
Simple Tips on Mylar Bags
There are a lot of misinformation out there regarding mylar bags. Let’s discuss and dispel some myths that don’t seem to go away.
- If your mylar bag doesn’t have that “vacuum packed” look, it isn’t sealed properly. Oxygen absorbers absorb oxygen not air. It is common to still see a slight bulge in the bag after it is sealed. As long as no air is escaping when you squeeze slightly, you should be good.
- If your mylar bag fails the flashlight test, it is useless. This is not true, light can shorten shelf life but mylar shades its contents very well. If kept in a cool and dry area out of direct sunlight, your food will store for decades.
Mylar Bags aren’t Just for Food Storage
Mylar bags, oxygen absorbers or moisture absorbers (desiccant) are a great way to preserve other supplies.
- Valuable books and papers can be stored for a SHTF situation.
- Handguns and ammunition can be stored and kept dry and corrosion free
What Should Not Be Stored in Mylar Bags?
- Don’t store sugar in mylar with oxygen absorbers
- Don’t store salt in mylar with oxygen absorbers
- Don’t store Baking soda/baking powder in mylar with oxygen absorbers
- Don’t store flour for the long term
- Any food that contains moisture
- Any food that contains fat, the food will go rancid and this includes nuts
- Brown rice should not be store long term
- Generally, food must have 10% or less moisture to be packaged in airtight containers
What Can I Store in Mylar Bags?
- Dehydrated fruits and vegetables
- Grains
- Pasta
- Sugar (without oxygen absorbers)
- Salt (without oxygen absorbers)
- Dried beans
- Powdered milk
- Cereal
- Spices
- Instant Coffee
Final Thoughts on Mylar Bags
When you are ready to start packaging your own food for long-term storage, mylar is the king of storage options. Once you get the hang of sealing them, they are a simple way to store dry goods. Just make sure your seal is good and you are storing your food in a cool and dry area free of direct sunlight.