Proper sealing of mylar bags is an important step in the effective packaging of the product. You cannot protect the product if you are unable to properly seal the bag. Even if you are using the highest quality mylar pouches. When you professionally seal the bag, you create an oxygen and moisture barrier that fully protects the packed items. You can get major benefits such as: 

• Proper sealing reduces product returns.
• Minimizes spoilage
• Protects brand reputation
• Maintains consistent product quality throughout storage and transportation
• Increases shelf life of stored foods and emergency supplies

Whether you are using custom printed mylar bags or a vacuum seal pouch, you have to understand correct sealing techniques to ensure perfect product packaging. In this blog, you will understand everything you need to know. 

Why Is Proper Mylar Bag Sealing Important?

Mylar bags are manufactured with a polyester film that is known as BoPET. These bags have multiple layers that create an excellent barrier against external contaminants. Despite having such food quality barrier layers, these bags are able to fulfill their requirement only when they are sealed professionally. When you properly seal a bag, you can: 

• Prevent oxygen entry to the bag
• Moisture and humidity blockage will be easy 
• The aroma and flavor of the food will be retained
• You can maintain the nutritional value of the food
• Extend shelf life for dry foods
• Prevent insect infestation
• Reduce freezer burn
• Improve transportation safety
• Protect product quality during long-term storage

To support food safety and quality, brands can also select airtight sealing. This will reduce contamination risk through the supply chain and give your brand an edge over your competitors. 

Materials Required Before Sealing Mylar Bags

The right sealing can be done only when you have selected the right material. Every component of the packaging of heat seal bags influences the overall performance of the packaging. The following are the essentials of sealing Mylar bags and pouches: 

Food-Grade Mylar Bags

Choose the bags based on the food requirement. You will need 3.5 to 4 mil thickness of the packaging that will give sufficient protection. On the other hand, bulk foods need 5 to 7 mils of material thickness. Finishing of the bags can be chosen based on the overall theme of your brand, such as gloss or matte. 

Oxygen Absorbers

Another very important part of the packaging is the oxygen absorber that is essential for long-term storage of low-moisture food items. These small packets remove trapped oxygen inside the bags and reduce the oxidation of the product. It is also essential to limit mold growth. Once you open the bags, the absorbers immediately react with the air. So only open the quantity that you need for immediate use and reseal the unused packet immediately. You can select an oxygen absorber based on the following specifications. 

• Bag volume
• Product density
• Remaining headspace

Dry Food Products

Food Mylar packaging bags are the best option for foods that have less than approximately 10 % moisture. Food items that have high oil and moisture content need a different type of packaging, as they deteriorate faster. Some of the common food items are as follows: 

• White rice
• Dry beans
• Pasta
• Oats
• Flour
• Powdered milk
• Freeze-dried foods
• Dehydrated vegetables
• Coffee beans
• Baking ingredients

Optional Desiccants

There are several packaged items that need protection from humidity rather than oxygen. For such food items, desiccants are used that can absorb excess moisture. Desiccants and oxygen absorbers have different functions and should not be considered as each other’s alternative. 

Essential Tools for Sealing Mylar Bags

There are certain things that are required for the perfect sealing of Mylar bags. You can improve consistency and efficiency of the packaging that will impact the seal integrity. 

Impulse Heat Sealer

An impulse heat sealer is a perfect solution for commercial packaging sealing. It is ideal for businesses that produce large quantities of flat mylar pouches on a daily basis. You can get the following benefits with the right heat sealer, such as: 

• Uniform sealing temperature
• Consistent seal width
• Fast production speed
• Repeatable results
• Minimal operator error

Clothes Iron

A standard household iron is a perfect and popular option for home food storage applications. You have to set it to medium or wool temperature without steam. Then you can create a strong seal that is suitable for emergency food storage and small packaging projects. 

Hair Straightener

Another thing that you can select for sealing mylar bags is a straightener. It has narrow plates that provide excellent control while producing even pressure along the sealing edge of the bags. This will work well for the following: 

• Small Mylar pouches
• Sample packs
• Coffee bags
• Cannabis packaging
• Snack-size packages

Vacuum Sealer

Vacuum sealing increases the shelf life of the food items and is compatible with channel strips that will allow excess air removal before the completion of the final heat seal. This hybrid approach will create a stronger storage environment for several types sof [product packaging. 

Flat Surface

Make sure you are sealing the bags with a flat surface that has a smooth surface and is heat-resistant. You can either use wood boards or silicone mats. Folded cotton towels are also a good option. A flat surface ensures that there is consistent pressure across all the surfaces. 

Scissors and Digital Scale

They create a clean and clear mylar bag opening after sealing. Digital scales offer accuracy for commercial packaging operations and give consistent portions. If you are at home, you can merely rely on scissors. 

Step-by-Step Process for Mylar Bags Sealing  

You have to follow a systematic process to minimize sealing failure. Professional-level packaging also requires that your brand consistently provides protected products. Every step of your process is vital and gives an airtight barrier that preserves freshness through storage and delivery. You may sell must involve the following steps for error-free bag sealing. 

Step 01: Prepare the Product Before Sealing

Before sealing the bags, accurately prepare the product so that the airtight packaging can retain its quality for months. If your product is not of good quality, then a quality seal will not be able to protect it. For commercial packaging operations, the preparation of the right product is a part of quality control. 

Packaging does not enhance the quality but protects what already has. So, make sure that the bag is clean and completely dry before adding the product. Trapped moisture can encourage mold growth. For long-term storage, your product must have less than 10% moisture. Freeze-dried and dehydrated food can perform perfectly at less than 5 % of moisture. After you have poured the food, remove any residue from the sealing area. Unless you do not immediately need them, make sure that the oxygen absorbers are packed in their original packaging. 

Step 02: Fill the Mylar Bag Correctly

Fill the bag while leaving 4 to 6 inches of empty space at the top. This headspace will provide enough room for excess air and make it easy for the heat sealer to create a straight and uninterrupted seal. Do not overpack the food, as it will create unnecessary pressure on the seal and increase the risk of punctures. This is important for grains that have sharp edges for die cut mylar bags, as they may cause punctures due to their sharp edges. After filling the bag, tightly tap it on a flat surface to eliminate the trapped air pocket. This will improve packaging stability and help oxygen absorbers to work efficiently. 

Step 03: Add the Correct Oxygen Absorber

The addition of oxygen absorbers is necessary as they improve shelf life by preventing oxidation. It retains the nutrient content of the packed items and enhances shelf life. The selection of the right quantity of oxygen absorbers is based on the following. 

• Bag dimensions
• Product density
• Remaining headspace
• Product type

Dense product items like rice leave more air space between individual grains. On the other hand, powdered items have less space between the individual particles. So the selection of oxygen absorbers also depends on the type of food item you are going to pack. After you have used the absorbers, immediately reseal the bags inside an airtight Mylar bag or glass jars. If humidity control is necessary, then use food-grade desiccants in the packaging. 

Step 04: Remove Excess Air

Before sealing the bags, remove excess air without crushing the packed item. For dry foods, you can press the bags upward. At a commercial level, you can combine this manual process with vacuum-assisted equipment. For smooth mylar bags, you will need a vacuum channel strip.This is because standard vacuum sealers cannot effectively remove air from non-textured films. You can complete the heat sealing process after vacuum sealing. Avoid compressing delicate food items or freeze-dried products, as this can damage product quality and alter the appearance. The objective is to reduce oxygen, not fully remove it manually. 

Step 05: Heat Seal the Mylar Bag

This is one of the essential steps for the preservation of the food items. When you heat seal the bag, you permanently bond the food-grade polyethylene inner layer of mylar bags. This creates an airtight barrier against oxygen and other contaminants. There are several sealing methods that are considered effective. Such as: 

• Impulse heat sealer
• Continuous band sealer
• Clothes iron
• Hair straightener
• Flat bar heat sealer

Make sure to apply consistent heat and steady pressure. Besides this, it is also essential to ensure that you have applied heat for a sufficient duration. This will create a continuous and straight edge-to-edge seal. If you are doing it at a commercial level, then make sure that you have selected a double and back seal bag. The double seal must be added ¼ inch above the first seal. It will give additional protection against accidental seal failure during transportation and handling. Allow all the seals to cool naturally before touching or testing them. If you move the bags when the plastic is still soft, you may weaken the seal. 

Step 06: Inspect and Test the Seal

Seal verification is essential for quality assurance. You can begin with visual inspection, and a good seal of mylar bags must have the following features: 

• Smooth
• Straight
• Continuous
• Uniform in width
• Free from wrinkles
• Free from gaps
• Free from burn marks

After you have done a visual inspection, you can perform a gentle pull test. This can be done by holding both sides of the sealed edges and applying pressure. If your seal is properly fused, it will remain intact. You can perform a leak test by gently compressing the packaging for small batches. Some brands select a water immersion test on sample packaging and identify microscopic leaks. If you have detected any defect, trim away the failed section and slightly adjust the heat and dwell time. These simple quality assurance tests before sealing the rest of the bag will eliminate major damage to your batch. 

 Step 07: Label and Store Properly

Even if you have properly sealed the bags and have used proper storage conditions, you have to store the bags in proper storage conditions. Clear labelling will make your inventory management easy and simplify product rotation. This will also make your food safety documentation easy. Immediately label each package with the following specifications: 

• Product name
• Packaging date
• Batch number
• Oxygen absorber size
• Expiration or rotation date

If you do not want to incur any damage to your packed food item, make sure your food is stored in locations that are: 

• Cool
• Dark
• Dry
• Clean
• Pest-free

70°F (21°C is an ideal temperature for storage. If you further reduce the temperature, the chemical reaction will slow down further, and food degradation will be slowed down. Large mylar must be placed in a bucket or large containers to protect them from rodents and physical damage during shipping. If the storage conditions are ideal, your food can maintain its quality for decades. 

Final Words!

The sealing of a mylar bag is not a one-step process but needs a series of steps for perfect storage. From the preparation of food for storage to the final heat sealing, each step is critical to quality. Besides the quality of the packaging seal, it is also essential that the quality of your bags is perfect. For perfect mylar bags, you can contact Mylar Bags Makers. We specialize in the manufacturing of mylar pouches with all the specifications you need to ace. So call now!