Why Use Mylar Bags in Food Storage?


How do you store your food long term?

There are different ways people do it. Some use storage containers, and others use vacuum-sealed bags. But from experience, I know that many preppers use Mylar bags.

Mylar Bags on the table

But why use Mylar bags in food storage? The reason why Mylar bags are used in food storage so often is that they are very durable and provide excellent protection against air, humidity, and light. This makes Mylar bag the perfect solution for storing large quantities of food for large amounts of time.

If you have never heard of Mylar bags, you probably just thought to yourself, “Wait, what is that?” Well, that was my reaction, at least when I first stumbled upon these bags.

Below I will answer this question as well as other important questions like what makes them such a go-to option and how good they are and why use them for food storage.

What Is a Mylar Bag?

The history of Mylar dates back to the 1950s when DuPont first developed it. Mylar is a trademarked brand owned by DuPont, and it is referring to a specific type of plastic sheet products.

Mylar bags and some nuts inside

Mylar bags are made from stretched PET (Polyethylene terephthalate). The material Mylar bags are made of is also referred to as BoPET (which stands for biaxially-oriented polyethylene terephthalate).

This particular type of plastic or polyester film is manufactured in many different types, forms, thicknesses, and finishes.

Mylar bags are being used for a wide variety of different purposes, one of which is food storage.

Mylar bags intended for food storage are usually made from PET, which is attached to aluminum foil. The combination of these two materials possesses qualities that make it an excellent choice for long term storage.

Reasons Why You Should Use Mylar Bags for Food Storage

So why exactly is Mylar used in food storage? Let’s take a more in-depth look.

Mylar Bags Provide Superior Protection

Mylar is a very durable material capable of providing excellent insulation. It has a high tensile strength, which makes it flexible too.

Mylar bags with zip lock

All of these properties are very important for several reasons.

  • Mylar bags can be filled with high amounts of food and be stored long-term without having to worry about the bag ripping and breaking;
  • What is more, Mylar is an excellent insulating material that can keep the elements outside from entering inside. Mylar is almost impermeable; thus it prevents moisture, gasses, and light from damaging the food inside;
  • Mylar bags are very flexible, which means that you can remove all the air inside and have one nicely and tightly packed package. No air also means no oxidation;
  • Mylar bags will keep any bugs and insects out; and
  • Mylar bags will also preserve the nutrients in the food.

Mylar bags are used in conjunction with oxygen absorbers, which are known to perform better than vacuum sealing. Oxygen absorbers absorb up to 99.99% while vacuum sealing removes about 99.50%.

Another aspect that makes Mylar bags better is the fact that the thicker bags can significantly reduce the amount of air that can get inside the bag with time. For example, plastic bags breathe, which can lead to infiltration of air in the bag over time.

All this means that the food you stored in the Mylar bags will stay fresh. Even spices that you may have packed back 10 or 15 years ago will keep their flavor and aroma.

Mylar Bags Come in Different Thickness

There are several aspects of Mylar bags that you have to consider before using them for food storage.

Mylar bags come in different thicknesses. The thickness will affect how well insulated and protected from the outside elements your food will be.

The thicker the bag, the better the protection from things like humidity, and UV light will be. But that also makes the bag stiffer and more expensive.

The thinner the bag, the more flexible it becomes, but it also provides less insulation. These are cheaper but can also be penetrated if you place some harder foods inside.

Mylar bags usually come in varying thickness ranging from 3.5 to 7.5 mil.

The best thickness for long term food storage is about 5 mil and higher. Anything below is not going to be enough to provide reasonable protection and insulation to your food. With thinner Mylar bags of 4.5 mils and less, you can even see the light pass through them.

Mylar Bags Come in Different Sizes

Mylar bags also come in different sizes ranging from 5 gallons down to about a pint or so. The different sizes also come in different thicknesses, so you are almost guaranteed to find something that you like.

  • Larger Mylar bags are best used for long term storage of large quantities of food like legumes, white rice, cereals, pasta, and flour;
  • Smaller is better for storing smaller amounts of food that you can use more frequently; and
  • The tiniest bags are great for storing seeds, spices, and other condiments.

The right size will vary depending on your personal needs. However, the most widely used sizes are two:

  • The larger 5-gallon Mylar bags are ideal for long term storage of large amounts of food; and
  • The smaller 1-gallon bags are suitable for storing smaller amounts of food that they can use more frequently.

Mylar Bags Are Easy to Seal and Keep Airtight

Another reason why you should use Mylar bags for food storage is that they provide one of the highest quality airtight sealings.

I have seen multiple videos about vacuum sealing Mylar bags. However, it seems like this method doesn’t work so well.

The vacuum-sealed bags are usually very ineffective, and it doesn’t take much to break the vacuum sealing.

With Mylar bags, you do not have to worry about that. The material Mylar bags are made of allows it to be heat sealed.

Fill the bags with the desired food, add the air absorbers, get as much air out as possible, and you are good to go and seal it.

Usually, one of the better alternatives is to use a hair straightener or a crimping iron. All you have to do is go over and across the edge of the bag and hold it with the hair straightener for about 3 to 5 seconds.

It takes no more than a minute, and the end result is a tightly sealed bag that will have as little air in it as possible.

Mylar Bags Can Be Used for Long Term Storage

Mylar bags are arguably the best way to store food long term. They can be used for almost any type of food that you intend to store for more than 1 year.

For example, legumes and white rice have a shelf life of about 2 to 5 years. When properly stored with oxygen absorbers in a Mylar bag, this time period can go up to and over 25 years.

Some other foods tend to have a shorter shelf life like oat groats and brown rice, which is usually about 6 to 12 months. This happens due to their higher oil content. Long term storage of oils has been a well-known problem. Even in the absence of oxygen, these foods will still turn rancid over time.

In these cases, with foods that have high amounts of oil and polyunsaturated oils, even a Mylar bag will not help much. This is why often these foods need to undergo different preparation methods before being stored long term.

Combining the right pre-storage steps and using a Mylar bag with oxygen absorbers can increase the storage life of brown rice up to 7 or 10 years.

A video I found on youtube by Iridium242 talking about this Mylar bags and how in daily life we easily use it. Watch the video below for more details:

Mylar Bags Are Reusable

Many different long-term storage bags and containers can be used only once. And once you open them, they cannot be used again.

However, this is one of the areas where Mylar bags really shine through. The material of Mylar bags and the way the bags are used allows them to be reused multiple times.

All you need to do is wash the bag, let it air dry, and you can fill it up with food and seal it again.

Reasons Why You Should Not Use Mylar Bags for Food Storage

Mylar Bags Are Pricey

Mylar bags are not super expensive. But compare them to vacuum-sealed plastic bags, and you will see the difference. Especially with the thicker and larger Mylar bags.

The larger 5-gallon 7-mil Mylar bags can cost anywhere between $2 to $5 per bag. If the price is a concern, then maybe Mylar bags are not the best option for you.

Some of the thinner Mylar bags are cheaper. However, frequently they are not a good alternative. Food that may have sharp edges can penetrate the bag, especially when kept in larger amounts. Also, the light can penetrate these, which can reduce the storage time significantly.

Mylar Bags Are Not See-Through

The next thing is that Mylar bags are not transparent. This means that you always need to make sure to label them to keep track of what is inside.

This, arguably, is not a huge drawback, but it is a small inconvenience that you have to deal with, nonetheless.

Mylar Bags Cannot Be Reused Indefinitely

The next drawback is that although, as previously mentioned, they can be reused multiple times, Mylar bags cannot be reused indefinitely.

Each time you open a sealed Mylar bag, you will cut small parts of it. Then you can reseal it again, but when you open it for a second time, you will remove small parts of the bag yet again.

As you can see, every time you open the Mylar bag after it has been sealed, it will become smaller and smaller until it will not be usable anymore.

This is something to keep in mind and the main reason why I recommend using larger bags of no less than a gallon.

A video where we can learn some of the mistakes along the way using this Mylar bags you can watch on this video. Why this bag is failed to keep the long time storage?

Mylar Bags Need Extra Protection

When we are storing food long term in a Mylar bag, we need to take a few extra precautions.

Rodents are a well-known problem when it comes to storing food as well. Even a Mylar bag will not be enough as rodents can chew right through it. And let’s not forget we are talking about storing food for many years if not decades.

This is why it is recommended to use larger Mylar bags in tandem with a hard plastic bucket (and buying extra buckets makes the whole thing even more expensive).

What the majority of people do is a couple of 5-gallon Mylar bag with a 5-gallon hard plastic bucket. You place the Mylar bag inside the bucket, fill it all up as you would normally do, add the oxygen absorbers, seal the bag, and close the lid of the bucket.

Do not forget to label the bucket so that you know what is inside.

It is recommended to use only new buckets made of food-grade plastic designed for food storage. Old second-hand buckets may pose some dangers and hazards as you will never be sure what has been stored in them before.

Mylar Bags May Be a Potential Health Hazard

Mylar bags are made from PETE (or PET). This type of plastic is often used for making soft drink bottles, fruit juices, plastic containers, mineral water, cooking oil, condiment bottles, shampoos, and so much more.

The good news is that the PET does not contain the infamous BPA.

However, there is emerging data that links PET plastic to the same health problems associated with BPA. German scientists have found that some chemical compounds can leach from plastic PET bottles, and they can interfere with the hormones the same way BPA does.

Although more data is needed, and experts say it is too early to say whether or not PETE could be harmful, the question of how safe PET is remained.

Some people may argue that almost every single product that we have come in contact with has been in contact with PET plastic at one time or another. And many experts still consider it to be safe for food storage.

With that being said, Mylar bags are usually FDA approved and USDA compliant, so they are considered safe, and many people have been using Mylar bags long term without any side effects.

However, in my opinion, the compound effect from all the plastic should not be underestimated.

In addition to that, I feel like it is worth mentioning that not all Mylar bags are created equal. There is some information suggesting that certain Mylar bags, especially the cheaper ones, maybe laminated with different chemicals, which may be of lesser quality and thus not always be safe for food storage.

I would recommend you to err on the side of caution and always do your research before buying a certain off-brand Mylar bag.

Mylar Bags May Be Difficult to Recycle

Mylar bags do not biodegrade; thus, they should never simply be thrown out.

What makes matters a lot worse is that, although Mylar bags are recyclable, not all recycling companies may be able to accept them.

Resources I Used:

  • https://www.grafixplastics.com/grafix-plastics/plastic-film-plastic-sheet-faq/mylar_what/
  • https://www.grafixplastics.com/grafix-plastics/plastic-film-plastic-sheet-faq/mylar_what/mylar_apps/
  • https://en.wikipedia.org/wiki/BoPET
  • https://www.mylarshop.com/mylar-shop-articles/the-mylar-shop-mylar-bag-size-guide
  • https://www.survivalistboards.com/showthread.php?t=747081
  • https://www.youtube.com/watch?v=iHlVcf6KXo4
  • https://www.youtube.com/watch?v=OCQIsldIvEY
  • https://seedtopantryschool.com/storage-bags-mylar-vacuum-or-plastic-for-long-term-storage-what-works-best/
  • https://outdoors.stackexchange.com/questions/14040/what-are-the-pro-and-cons-of-vacuum-sealed-vs-mylar-bags-for-diy-dehydrated-food/14056
  • https://www.sorbentsystems.com/mylarinfo.html
  • https://practicalsurvivalblog.com/pros-cons-mylar-storage-bags/
  • https://www.ndspackaging.com/mylar-bags-how-they-work-and-why-you-should-use-them/
  • https://materialdistrict.com/material/mylar/
  • https://drinkpathwater.com/blogs/news/is-pet-plastic-bpa-free
  • https://www.cpme-pet.org/content/do-pet-bottles-or-containers-contain-bpa
  • https://www.abc.net.au/science/articles/2009/04/29/2555698.htm
  • https://outdoors.stackexchange.com/questions/11340/is-it-safe-to-add-boiling-water-to-mylar
  • https://www.usaemergencysupply.com/emergency-supplies/food-storage-equipment/mylar-bags-for-food-storage
  • https://www.usaemergencysupply.com/emergency-supplies/food-storage-equipment/mylar-bags-for-food-storage
  • https://www.skilledsurvival.com/mylar-bags-food-storage/

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