OTR In Packaging: A Complete Guide To Oxygen Transmission Rate

Oxygen exposure can affect the quality, freshness, flavor, aroma, and shelf life of many packaged products. For products such as coffee, snacks, nuts, confectionery, and other oxygen-sensitive foods, controlling the amount of oxygen that reaches the product is often one of the most important jobs a package has to do.

This is where Oxygen Transmission Rate (OTR) becomes important.

OTR is a technical measurement used to understand how much oxygen can pass through a packaging film under specified testing conditions. Manufacturers and product brands use OTR data when evaluating whether a film or multilayer structure whether that’s a stand-up pouch, a flat bottom pouch, or a run of roll stock destined for a form-fill-seal line can provide the oxygen protection a particular product needs.

Understanding OTR can help packaging teams make better decisions about film materials, barrier layers, laminate structures, and overall package design. But OTR is not simply a matter of choosing the film with the lowest number. The right oxygen barrier depends on the product, desired shelf life, storage conditions, package format, and other performance requirements working together.

In this guide, we’ll explain what OTR means, why it matters, how it’s measured, which materials provide oxygen barrier properties, and how to translate that into an actual packaging decision.

What Is OTR In Packaging Film?

OTR stands for Oxygen Transmission Rate. It measures the amount of oxygen that passes through a packaging material over a specific period under defined testing conditions.

OTR is commonly expressed as: cm³/m²/day

This represents the volume of oxygen that passes through one square meter of packaging material in 24 hours under specified test conditions. In simple terms, OTR helps indicate how well a packaging film resists oxygen transmission.

• Lower OTR = less oxygen passing through the material
• Higher OTR = more oxygen passing through the material

A lower OTR generally indicates stronger oxygen barrier performance. However, the ideal OTR depends entirely on the application. Not every product needs the highest possible oxygen barrier, and over-specifying barrier performance can add unnecessary cost to a packaging structure.

Why Is OTR Important In Flexible Packaging?

Oxygen can cause unwanted changes in products during storage. Depending on the product, oxygen exposure may contribute to oxidation, loss of flavor and aroma, color changes, nutrient degradation, and general deterioration of product quality.

For example, fats and oils oxidize when exposed to oxygen. This is a real concern for products like nuts, snacks, coffee, and pet food, all of which carry natural oils that degrade over time.

A suitable oxygen barrier built into chips packaging, cookie packaging, or dried fruit and nut packaging can help slow oxygen transmission and support the shelf life a brand is promising on the label. OTR is therefore particularly relevant whenever a packaging structure needs to actively manage oxygen exposure rather than just contain a product.

How Does Oxygen Pass Through Packaging Film?

Packaging films may appear completely solid, but oxygen molecules can still move through certain polymer materials. The process generally involves oxygen molecules dissolving into one side of the film, migrating through the material, and emerging from the other side.

The rate at which this happens depends on the characteristics of the material and the conditions under which it’s tested. Factors that can influence oxygen transmission include:

• Film material
• Film thickness
• Temperature
• Relative humidity
• Polymer structure
• Barrier coatings
• Lamination structure
• Manufacturing quality

This is why two films that look nearly identical on a roll can have significantly different OTR values once tested.

What Is a Good OTR for Packaging Film?

There is no universal OTR value that qualifies as “good” for every application. The required oxygen barrier depends entirely on the product and its packaging requirements.

A product that’s highly sensitive to oxygen may require a very low OTR, while a less sensitive product may perform adequately with a higher one. Other factors that shape the right target include:

• Required shelf life
• Package size
• Product oxygen sensitivity
• Storage temperature
• Relative humidity
• Headspace oxygen
• Packaging process
• Distribution conditions

The objective should be to select an OTR that delivers the protection a specific product actually needs, not to automatically default to the lowest number on a spec sheet.

Which Packaging Films Provide Oxygen Barrier Properties?

Different packaging materials offer different levels of oxygen barrier performance. Some are primarily chosen for strength or sealing, while others are built into a structure specifically to provide barrier protection.

PET

Polyethylene terephthalate, or PET, is commonly used as an outer layer in flexible packaging structures. It offers good mechanical strength, dimensional stability, and printability, along with some baseline barrier performance. Standard PET on its own, though, usually isn’t enough for applications that need a very high oxygen barrier.

BOPP

Biaxially oriented polypropylene, or BOPP, is widely used because of its clarity, stiffness, moisture resistance, and printability  qualities that matter in formats like flow wrap packaging and lay flat pouches. Standard BOPP does provide some barrier, but it’s rarely used alone when a very high oxygen barrier is the priority.

PE

Polyethylene is widely used as a sealant layer across most flexible formats, including custom pouches and side gusseted bags. It offers strong heat-sealing properties, flexibility, and reliable product contact, but standard PE has limited oxygen barrier compared with dedicated high-barrier materials.

EVOH

Ethylene vinyl alcohol, or EVOH, is known for strong oxygen barrier properties and is often incorporated into multilayer structures when oxygen protection is a priority. Its performance can be affected by humidity, so the layers surrounding it in the laminate matter as much as the EVOH itself.

Aluminum Foil

Aluminum foil provides an extremely strong barrier against oxygen, moisture, light, and other external factors when used correctly in a flexible structure. This is one of the reasons foil-based laminates and custom mylar bags remain a go-to choice for coffee, supplements, and other products that need maximum shelf stability.

Metallized Films

Metallized films carry a very thin metallic coating, commonly aluminum, that improves barrier performance while keeping the structure lightweight and flexible. Performance depends on the specific film, coating thickness, laminate construction, and manufacturing process  which is why working through the full structure with a packaging partner matters more than comparing single-layer specs in isolation.

OTR And Multilayer Packaging Structures

Flexible packaging often relies on multilayer film structures rather than a single material, with each layer doing a different job:

• Outer layer → Printing, appearance, and mechanical protection
• Barrier layer → Oxygen, moisture, or light protection
• Sealant layer → Heat sealing and product-contact performance

This layered approach lets manufacturers combine materials with different strengths into one structure  for example, a printable outer film, a dedicated barrier layer, and a polyethylene sealant layer, laminated together and converted into finished roll stock or pre-made pouches.

The final OTR of the packaging structure depends on the materials, thicknesses, construction, and manufacturing process used across every layer. This is why it’s important to evaluate the complete structure rather than judging one film layer on its own.

OTR vs. WVTR In Packaging

OTR and WVTR are two different barrier measurements that often get discussed together.

• OTR  Oxygen Transmission Rate: measures the amount of oxygen that passes through a packaging material.
• WVTR  Water Vapor Transmission Rate: measures the amount of water vapor that passes through a packaging material.

Both can matter when selecting flexible packaging. A snack, for instance, may need oxygen protection to reduce oxidation while also needing moisture protection to keep its texture from going stale or soft. A well-built structure whether it’s a quad seal pouch or a digital printed pouch  often needs to deliver both appropriate OTR and WVTR performance at once.

How Is OTR Measured?

OTR is measured using specialized testing equipment under controlled conditions. During a test, a film sample is placed between environments with controlled oxygen concentrations, and the equipment measures how much oxygen passes through the material over a set period.

Testing conditions can include:

• Temperature
• Relative humidity
• Oxygen concentration
• Film thickness
• Test area
• Pressure conditions

These conditions matter because OTR performance can shift depending on the environment it’s tested in. For that reason, OTR values should only be compared using the same, or reasonably comparable, testing conditions. A stated OTR value should always be evaluated alongside the conditions under which it was measured.

Does Film Thickness Affect OTR?

Film thickness can influence oxygen transmission. For many materials, increasing the thickness of a barrier layer reduces the amount of oxygen that passes through. But adding thickness isn’t automatically the right fix.

A packaging structure needs to balance oxygen barrier performance against other requirements, including:

• Flexibility
• Sealability
• Mechanical strength
• Weight
• Cost
• Processability
• Sustainability

The type of material used for the barrier layer is often just as important as how thick it is  a well-chosen thin barrier layer can outperform a thicker layer of the wrong material.

OTR And Product Shelf Life

OTR plays a real role in packaging development because oxygen exposure can shape the shelf life of oxygen-sensitive products. Coffee is a familiar example  it loses desirable flavor and aroma once exposed to oxygen, which is part of why coffee bags are so often built with foil laminates or metallized layers and one-way degassing valves. Products containing fats and oils, from nuts to pet food, experience similar oxidation risk.

A structure with an appropriate oxygen barrier can help reduce oxygen ingress and support product quality throughout storage. That said, OTR is only one piece of the shelf-life picture. Other contributing factors include:

• Initial oxygen inside the package
• Headspace volume
• Product formulation
• Package size
• Seal integrity
• Storage temperature
• Humidity
• Light exposure
• Packaging process
• Distribution conditions

Even excellent film OTR performance doesn’t automatically guarantee a target shelf life if these other variables aren’t accounted for.

Common Packaging Formats Built Around Oxygen Control

Barrier performance isn’t just a film property sitting on a data sheet  it shows up in the everyday packaging formats brands actually order. A few formats worth knowing:

• Stand-up pouches are frequently built with barrier laminates for snacks, coffee, and pet food, since they need to hold shape on shelf while protecting the product inside.
• Custom sachet packaging and stick pack packaging rely on high-barrier film in a small format, often for single-serve powders or ingredients that oxidize quickly.
• Vacuum seal bags take barrier control a step further by removing headspace oxygen at the point of sealing, which is useful for products where residual oxygen inside the pack  not just transmission through the film  is the bigger risk.
• Resealable bags and pouches need to account for oxygen re-entering the package every time it’s opened after the first use, which is a factor that a single OTR number doesn’t capture on its own.
• Custom mylar bags combine a metallized or foil barrier with a flexible pouch format, commonly used where long-term storage stability matters more than shelf transparency.

Matching the barrier structure to the right format is often just as important as choosing the barrier material itself.

OTR in Different Flexible Packaging Applications

Different products carry very different oxygen barrier requirements.

Coffee Packaging
Coffee is highly sensitive to oxygen, since oxidation directly affects flavor and aroma. Tea and coffee packaging often calls for a high-barrier structure specifically designed to limit oxygen ingress over an extended shelf period.

Snack Packaging
Many snacks contain fats and oils that are vulnerable to oxidation. Appropriately barrier-rated chips packaging and cracker packaging pouches can help maintain flavor and crunch for longer.

Nuts and Seeds Packaging
Nuts and seeds contain oils that oxidize over time. Dried fruit and nut packaging with the right oxygen protection helps maintain product quality between production and the point of sale.

Chocolate and Confectionery Packaging
Chocolate bar packaging and candy packaging may need a combination of oxygen, moisture, aroma, and light protection depending on the specific formulation and ingredients involved.

Pet Food Packaging
Pet food frequently contains fats and oils susceptible to oxidation. An appropriate barrier structure in pet food packaging or dog food packaging helps protect product quality across a full bag’s intended shelf life, especially in large-format bags that stay open in a pantry for weeks.

Dairy and Milk Powder Packaging
Milk powders and other dried dairy products are also prone to oxidative flavor changes, which is why dairy powder packaging is another category where barrier structure gets evaluated closely alongside moisture protection.

How to Choose the Right OTR for Your Packaging Film

Choosing an appropriate OTR should start with understanding the product, not the film catalog.

1. Determine product sensitivity. Identify how the product responds to oxygen exposure and whether oxidation visibly affects its quality.
2. Define the target shelf life. Determine how long the product needs to maintain its intended quality under expected storage conditions.
3. Understand storage and distribution conditions. Temperature and humidity influence packaging performance, so consider what the package will experience throughout its journey.
4. Evaluate the complete film structure. If the final package is a laminate or multilayer construction  like most flexible packaging  assess the full structure rather than one individual film layer.
5. Consider other barrier requirements. Oxygen may not be the only concern; the package may also need moisture, light, aroma, grease, or puncture protection.
6. Consider package design. Package size, shape, headspace, and seal area all influence overall performance, which is part of why format choice and barrier choice should be discussed together.
7. Test the finished package. Material specifications are useful on paper, but testing the actual finished package gives a far more reliable read on real-world performance.

Common Mistakes When Evaluating OTR

Understanding OTR is important, but it’s also easy to misread the specification.

• Assuming the lowest OTR is always the best choice, when in reality the required barrier depends entirely on the product and application
• Comparing OTR values without checking the testing conditions they were measured under
• Evaluating OTR separately from the package construction  a high-barrier film can still underperform if seals or structure aren’t properly designed
• Treating OTR as a substitute for real-world package testing rather than one input among several

Frequently Asked Questions About OTR

1. What does OTR stand for in packaging? OTR stands for Oxygen Transmission Rate. It measures the amount of oxygen that passes through a packaging material under specified testing conditions.
2. Is lower OTR better? Generally, a lower OTR means less oxygen passes through the material, indicating stronger barrier performance. However, the required OTR depends on the product and application.
3. What is the difference between OTR and WVTR? OTR measures oxygen transmission, while WVTR measures water vapor transmission. Both properties may matter when selecting packaging film.
4. Does thicker packaging film have a lower OTR? Increasing the thickness of certain barrier materials can reduce oxygen transmission, but performance also depends on the material, structure, and testing conditions.
5. Which packaging material has the best oxygen barrier? Materials such as aluminum foil and specialized high-barrier laminates provide very strong oxygen barrier performance. The right material depends on the application and other packaging requirements.
6. Why is OTR important for food packaging? OTR helps packaging professionals evaluate how much oxygen can pass through a film. This matters for products where oxygen exposure may contribute to oxidation, flavor loss, or reduced shelf life.
7. Can OTR affect product shelf life? Yes. Oxygen transmission can contribute to product deterioration for oxygen-sensitive products. Shelf life, though, also depends on product formulation, package design, sealing, storage conditions, and initial oxygen levels.

Conclusion

OTR is an important technical measurement for understanding oxygen barrier performance in packaging film. It helps manufacturers and brands evaluate how effectively a material or structure limits oxygen transmission.

But selecting the right film requires more than choosing the lowest OTR on a spec sheet. Product sensitivity, shelf-life requirements, storage conditions, moisture barrier, seal integrity, package format, and overall film structure all need to be weighed together.

If you’re developing a barrier structure for a coffee bag, a snack pouch, or a pet food package, our team at Contipack Inc. can help match the right film, laminate, and format to your product’s actual shelf-life needs. Explore our full range of flexible packaging solutions, or get in touch to talk through your specific barrier requirements.