How Thick Should Mylar Bags Be for Food Storage

Mylar bags come in a variety of different sizes and thicknesses.

Choosing the size of the Mylar bags is usually not a problem – all you have to do is just decide on the quantity of food you want to store.

How Thick Should Mylar Bags?

However, choosing the right thickness of the bag for your individual needs can be a tricky thing to do.

So how thick should Mylar bags be for food storage? Mylar bags are available in thicknesses between 2 mils and 7.5 mils. For optimal protection, Mylar bags with a thickness between 5 and 7 mils should be used. Thinner Mylar bags below 4.5 mils should not be used as they will not provide reasonable protection against moisture and UV light and punctures.

With that being said, there are some caveats and interesting details when it comes to using Mylar bags.

Choosing the right thickness is paramount when we are looking for a good balance between optimal food storage and price.

If you are interested in learning more, continue reading below.

How Thick Are Mylar Bags?

Mylar bags are made from a metalized and stretched polyethylene terephthalate polyester.

Mylar Bags filled with beans

Mylar bags come in a number of different thicknesses starting from as low as 2 mils and going up to 7.5 mils.

“But what exactly is a mil,” you may ask me, “and is it that important?”

Here’s the thing.

A mil is a measure of thickness equal to 1-thousandth of an inch (0.001 inches or 0.0254 mm). To put things in perspective, consider the following. A human hair is, generally speaking, between 0.0006 to 0.007 inches thick. And the average hair thickness is considered to be around 0.002 inches.

So Mylar bags are going to be slightly thicker than a strand of human hair.

Although these numbers may seem really small, there is a very noticeable difference between the different mils.

Is the Thickness of a Mylar Bag Important?

The thickness of a Mylar bag is a crucial detail that deserves some attention for several reasons.

Mylar Bags black inside

Thin Mylar bags that are about 4 mils and less, you can see the light going through them. This means that thin Mylar bags do not offer proper UV light protection.

Light entering through the bag can speed up the spoilage of the stored food inside of them. Additionally, thin Mylar bags also do not provide good protection against humidity – which is yet another factor that will significantly reduce the storage time of the food items in the bag.

Thin Mylar bags are best for storing small amounts of food for shorter periods of time – no more than a couple of months if kept away from sunlight in a place with low humidity.

The type of food also matters – Thin Mylar bags are usually more flexible and pliable, and they are more prone to breaking and tearing when used for storing food that may have sharper and thinner edges.

Thick Mylar bags – 5 mils and above – offer superior insulation and protection against sunlight, humidity, and gasses. This makes the thicker Mylar bags the go-to choice if you are looking for means of storing dry food long term (typically more than a year).

The 5-mil Mylar bags are very thick and somewhat flexible, so they can still crinkle easily while a 7-mil bag will be very stiff.

Thick Mylar bags coupled with oxygen absorbers can be used for storing dry food for not just a few years but several decades if stored properly. Thicker Mylar bags are more durable and do not break or tear easily.

The thicker the Mylar, the more stiff and expensive it is.

Does the Thickness Affect the Mylar Bag Properties in Any Way?

Mylar bags are also reusable and, once opened, can be resealed again. The thickness of the Mylar bag will not affect its reusable qualities.

Mylar Bags black

Although Mylar bags provide great protection to the food stored inside against humidity, sunlight, and gasses, they do not offer good protection against pests. Rats and mice can chew right through the Mylar, and the thickness of the bag will not make a lot of difference.

Additionally, if the dry food you will place in the Mylar bags has been infested by some type of bugs like weevils, beetles, flour mites, Indian meal moths, or others, the thickness of the Mylar bag will not help in any significant way. Even with the added oxygen absorbers, you may not be able to get rid of these bugs.

The thickness of the Mylar bag does not affect the sealing process of the Mylar bag either. You can use a hair straightener or an iron to seal both thick and thin Mylar bags. The process is the same for all Mylar bags – use an iron set at medium to high heat and go across the bag for 2 or 3 seconds.

In other words, the thickness just adds additional protection against punctures and tearing and better insulation and protection against the elements. It makes the bag more durable and stiff but does not take away from its main qualities.

What Is the Right Mylar Bag Thickness for Storing the Different Types of Food?

A 4.5 mil Mylar bag is generally speaking a good place to start from. However, certain food items may need to be stored in thicker bags, while others will do just fine in thinner bags. Let’s take a look at a few examples below:

Type of FoodRecommended Mylar bag Thickness*
Grains (oats, wheat, barley, rye, and corn)5 mil and above
Legumes (pinto beans, red beans, pinto beans, and lentils)5 mil and above
Mashed potatoes4.5 mil and above
Pasta, macaroni, and spaghetti6 mil and above
Pancake mixes4.5 mil and above
Rice5 mil and above
Flour4.5 ml and above
Sugar5 mil and above
Spices4 mil and above
Seeds5 mil and above
Flowers3.5 mil and above

* There are no hard and fast numbers here. Generally speaking, some foods may have sharper edges and can puncture thinner Mylar bags, hence why, in some instances, thicker bags are recommended.

Additionally, the larger the quantity of food you will be storing, the thicker the Mylar bag you may need to use so that it doesn’t tear apart under its own weight.

For example, storing legumes in one or two-gallon 4.5 mil Mylar bags can be okay; however, if you go up to a five-gallon Mylar bag, you may need to go with 6 or 7 mil bags.

What Is the Best Mylar Bag Thickness for Long Term Food Storage?

For long term food storage, you want to go with thicker Mylar bags. The higher thickness will provide better insulation meaning your food will be stored safely, and the outside elements will not affect it significantly if at all.

The best thickness for long term storage is 5 to 7.5 mil. Mylar bags below 4.5 mils should not be used for long-term food storage as they provide less protection and insulation and may be easily punctured under the heavyweight of the food.

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7.5 Mil Mylar Bags/Pouches - Multiple Sizes Genuine Odor-Proof Aluminum Foil-Lined Bag for Long Term Food, Grain, Baking, Storage Container (50) (5"x7"x3"gussetted zip seal)
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Although the thicker Mylar bags are going to be very durable, Mylar is still a very tender material. Little things like your watch, bracelet, rings, tools, utensils, sharp edges can easily tear or poke a hole in the bag. So make sure to exercise extra caution.

What Is the Best Mylar Bag Thickness for Short Term Storage?

Thinner Mylar bags, especially under 3.5 mils, are more prone to punctures and tearing if used for storing certain types of food, especially in high quantities.

This is why thinner Mylar bags should be used for storing low quantities of food. Also, the reduced protection and insulation of these bags make them suitable for short term food storage only, especially if cost is a concern.

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Dry-Packs 60-1 Gallon ShieldPro Mylar Bags (10"x14") & 60-300cc Oxygen Absorbers (In packs of 20) For Dried Dehydrated and Long Term Food Storage - Food Survival,Silver,MB10x14-300CC-60PK-OB
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With that being said, short term storage can be achieved with Mylar bags with different thickness starting from 3.5 and going up to 7 mils.

How Much Do Thicker Mylar Bags Cost?

The most commonly used Mylar bags are usually a half-gallon, one gallon, and five gallons. And the actual cost of a Mylar bag will be a function of its size, thickness, and the number of bags bought.

  • Thinner 3 to 3.5 mil Mylar bags can sell for anywhere between $0.14 up to $1.
  • The slightly thicker 4 to 4.5 mil Mylar bags usually cost between $0.24 up to $2.9.
  • The 5 to 5.5 mil Mylar bags may sell for anywhere between $0.96 up to $3.5 for the larger bags.
  • And the thickest 7.5 mil Mylar bags will usually be the most expensive selling for $1.4 up to $3.7 for the larger bags.

Of course, these numbers are averages and can vary drastically, but they can be used as a good ballpark.

Usually, buying in bulk will be the cheapest way to buy Mylar bags.

Mylar bags are Very rarely sold in quantities less than 10 as this makes them very expensive. For example, in comparison, a single 7 mil 5-gallon Mylar bag can sell for as much as $6.5 apiece.

When it comes to Mylar bags, you get what you pay for.

Cheaper Mylar bags may not be of good quality. People have reported that cheaper and thinner Mylar bags may not hold up too well when it comes to long term storage, potentially ruining the stored food.

So I would recommend putting quality in the first place, especially since we are talking about food storage.

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