The answer is simple. Mylar bags for food storage should be at least 10 mil thick, 5 mil per side. Anything thinner increases the risk of oxygen penetration, tearing, and flavor or nutrient loss over time.

Opting for the proper thickness of Mylar bags when storing food is not merely a matter of choice but also directly affects the shelf life, oxygen protection, resistance to piercing, and security of the food stored over long periods. So many people wonder what thickness of Mylar bag they should use to store their food safely and effectively.

"Film thickness directly influences puncture resistance, durability, and overall barrier performance in flexible packaging. While barrier layers control oxygen and moisture transmission, sufficient thickness is necessary to maintain structural integrity during handling and long-term storage." - Dr. Barry A. Morris, Flexible Packaging Technologist

We will go over exactly how important thickness is, how mil works, and when it’s appropriate to use a thicker Mylar bag.

What Does “Mil” Mean When Talking About Mylar Bags?

Mylar bags are commonly measured using the mil (one thousandth of an inch) metric. When the Mylar is labeled 5, 7.5 or 10 mil this indicates the total thickness of the material that the bag consists of.

The durability of a Mylar bag for food storage will be determined by thickness in three primary ways:

• Oxygen and moisture barrier strength
• Resistance to punctures and pinholes
• Durability during sealing, stacking, and handling

While thin Mylar bags may appear to be acceptable initially, they will typically fail when properly stored in long-term conditions.

The 10 mil mylar bag is the minimum thickness that can provide safe food storage, especially for the dry goods which are stored in the food industry, such as rice, flour, beans, pasta, cereal, freeze-dried foods, etc.

Why 10 Mil Is the Minimum for Food Storage

Here are the reasons why the 10 mil is an important factor for food storage safety.

- Strong enough to impede oxygen from entering the bag when sealed correctly with an oxygen absorber.
- Durable enough to withstand tearing during the handling and storage of your food.
- Compatible with oxygen absorbers and will not fail by collapsing or cracking.
- Gives your food a long period of protection, which will last for years instead of months.

Any other bag lower than 5 mil thick on each side (10 mil total) will increase the likelihood that micro punctures cannot be detected and will result in the introduction of air and moisture inside the bag.

Why Food Brands Use Thick Custom Mylar Bags

Food brands choose to use thick custom Mylar bags for a reason. When it comes to protecting the flavor, freshness, or shelf stability of their products, thickness is an essential factor. Additionally, thick Mylar provides a better feel to customers when they hold their product in hand.

By using thicker Mylar, food brands are able to reduce spoilage, minimize returns and complaints from customers while maintaining the same premium appearance on the shelf.

Reasons for the use of thick custom Mylar bags by food brands:

1. Better barrier against oxygen and moisture to help carry the product longer
2. Greater puncture resistance and protection for sharp/dense food products
3. More reliable for heat sealing during high speed production/package operations
4. More effective at protecting foods from light that can oxidize/destroy ingredients.
5. Reduce the chances of pinholes developing due to rough handling and storage and shipping.
6. Provide a stiffer, more premium feel to the product giving it a higher perceived quality to the consumer

For many food companies, using thick custom Mylar bags means they have an insurance policy on the freshness, consistency, and reputation of their brand.

What Happens If Mylar Bags Are Too Thin?

The use of Mylar bags with thinner than 5 mil sides (i.e. 10 mil total) will lead to problems with mylar bags due to the following:

- There will be greater exposure to oxygen, increasing the probability of spoilage.
- There is a greater likelihood of holes created from the sharp edges of food that may puncture the bag.
- Weakness of the seal will result in failure at time of heat sealing.
- Less protection from light and moisture present in environment.

While many manufacturers promote these thinner bags as safe for storing food, they will accomplish best for storing items for a short time period, sizing and not intended for storing food.

Thicker Mylar bags work because of how their layered structure blocks oxygen, moisture, and light, which is explained in detail in How Do Mylar Bags Work?

Final Answer: How Thick Should Mylar Bags Be for Food Storage?