Understanding the Terminology

In the push for sustainable packaging, terms like “compostable” and “biodegradable” are often used interchangeably, yet they carry very different meanings. Both refer to materials that can break down under certain conditions, but the mechanisms, timeframes, and environmental outcomes differ significantly. For businesses and consumers aiming to reduce waste, it is critical to grasp these differences. This article provides an in-depth comparison, looking at standards, real-world disposal infrastructure, material types, and the implications for choosing the right packaging solution.

What Is Compostable Packaging?

Compostable packaging is designed to decompose in a controlled composting environment, transforming into carbon dioxide, water, inorganic compounds, and biomass—essentially nutrient-rich compost. The process is typically accelerated by heat, moisture, and aerobic microorganisms. To be labelled compostable, materials must meet strict global standards such as ASTM D6400 (North America) or EN 13432 (Europe). These standards require that at least 90% of the material breaks down into fragments smaller than 2 mm within 180 days in an industrial composting facility, and that the resulting compost does not harm plant growth.

Types of Compostable Materials

  • PLA (Polylactic Acid): Derived from corn starch or sugarcane, PLA is a bioplastic used for clear cups, cutlery, and films. It requires industrial composting conditions.
  • Bagasse: A fibrous by-product of sugarcane processing, often molded into plates, bowls, and clamshells. Bagasse is compostable in both industrial and home settings with good moisture.
  • Starch-Based Films: Made from potato or tapioca starch, these films are used for protective wrap or liner bags. They need high humidity and microbial activity.
  • PHA (Polyhydroxyalkanoates): Produced by bacterial fermentation of sugars or fats, PHA is marine biodegradable and compostable, but currently limited in commercial scale.

Industrial vs. Home Composting

Many compostable plastics like PLA require sustained temperatures of 55–60 °C, which are only achieved in industrial composting facilities. Home compost piles rarely reach such heat, so these items may not break down effectively. Some newer certifications (e.g., TÜV HOME) verify that a material can compost at lower temperatures (around 25–30 °C) within 365 days. It’s essential to check the certification label—industrial-compostable plastics should not be placed in backyard bins unless explicitly marked “home compostable.”

What Is Biodegradable Packaging?

Biodegradable packaging refers to materials that can be broken down by microorganisms into natural substances (water, CO₂, biomass) over time. However, the term “biodegradable” alone does not specify how long this process takes or under what conditions. Unlike compostable packaging, there is no universal timeframe or certification requirement for a product to be labeled biodegradable. A plastic bag marketed as “biodegradable” may take decades or longer to break down in a landfill, and it may leave behind microplastics or toxic residues if the formulation includes additives rather than true biobased polymers.

Materials Commonly Labelled Biodegradable

  • Oxo-degradable Plastics: Conventional plastics (e.g., polyethylene) with metal salts that accelerate fragmentation when exposed to UV and oxygen. These do not fully biodegrade and instead create microplastic fragments. Many countries and the EU are banning oxo-degradable plastics due to environmental concerns.
  • Biobased PET: Made partially from plant sources (e.g., bio-ethylene), bio-based PET is chemically identical to conventional PET and is not inherently biodegradable—it can be recycled but will not compost.
  • Paper and Cardboard: While technically biodegradable, most paper packaging is coated with polyethylene or other barriers that slow decomposition. Uncoated paper is fully compostable but is usually labeled simply as paper, not “biodegradable.”
  • Starch Blends: Some blends combine starch with polyolefins; these may partially degrade but leave persistent synthetic fragments.

The lack of a robust regulatory framework means that many biodegradable claims are unsubstantiated or even misleading. The European Commission’s Single-Use Plastics Directive restricts the use of terms like “biodegradable” on plastic products that are likely to be littered, acknowledging the risk of greenwashing.

Key Differences at a Glance

The following expanded comparison covers the essential factors that businesses and consumers should consider when evaluating packaging options.

Decomposition Timeframe

Compostable: Breaks down within 90–180 days under industrial composting conditions; home‑compostable variants may take up to 365 days. Biodegradable: No defined timeframe; can range from months to centuries depending on the material and environment. A biodegradable plastic bag certified to ASTM D5526 may degrade in a simulated landfill but still take hundreds of years in a real landfill with low moisture and oxygen.

End‑of‑Life Residue

Compostable: Leaves behind non‑toxic biomass that enriches soil carbon and nutrient content. Biodegradable: May leave microplastics or chemical residues if the material is designed for fragmentation rather than full assimilation by microorganisms. Oxo‑degradable plastics are notorious for this issue.

Certifications and Standards

Compostable: Rigorous certification programs exist: BPI (Biodegradable Products Institute) in North America, DIN CERTCO in Europe, and the Australian Standard AS 4736. Each requires third‑party testing. Biodegradable: Although standards like ASTM D6400 also apply to certain biodegradable plastics, many products labelled “biodegradable” carry no certification at all. In regions like the EU, unsubstantiated biodegradable claims are increasingly prohibited.

Disposal Pathways

Compostable: Must go to an industrial composting facility, a commercial organics stream, or a certified home compost bin. If sent to landfill or recycling, compostable plastics can contaminate recycling streams or fail to degrade due to anaerobic conditions. Biodegradable: Often disposed of in general waste; however, this means they end up in landfills where oxygen and moisture are limited, leading to little to no degradation. Some biodegradable plastics are designed for anaerobic digestion, but that infrastructure is still limited.

Cost and Material Performance

Compostable materials are generally more expensive than standard plastics and may have shorter shelf lives or lower moisture barrier properties. Biodegradable options—especially oxo‑degradables—are cheaper but come with higher environmental risks. For high‑barrier food packaging (e.g., long‑shelf‑life snacks), conventional plastics are still the norm. However, new multi‑layer compostable films are emerging that offer comparable performance.

The Certification Landscape

To avoid greenwashing, look for recognized certification logos on packaging. The most important certifications include:

  • BPI (Biodegradable Products Institute): Widely recognized in the US and Canada. Products with the BPI logo meet ASTM D6400 (compostable plastics) or D6868 (paper coated with compostable plastic).
  • DIN CERTCO / Seedling Logo: European certification to EN 13432. The seedling logo is often considered the gold standard in Europe for industrial compostability.
  • TÜV Austria / OK Compost HOME: Certifies materials that can decompose in home compost piles within 12 months. Look for “OK Compost HOME” on packaging.
  • ABA (Australian Bioplastics Association): Administer the AS 4736 and AS 5810 standards for industrial and home composting respectively.
  • CBP (Certified Biobased Product) – USDA: Indicates renewable content but does not certify biodegradability or compostability.

When evaluating certifications, always check the issuing body’s website for the product’s listing. Some manufacturers use generic eco‑logos that resemble certifications but are not backed by third‑party tests. A reliable resource is the Biodegradable Products Institute website, which maintains a searchable database of certified products.

Disposal Infrastructure Realities

A packaging material’s environmental benefit is only realized if it enters the correct disposal system. Unfortunately, most regions lack adequate composting infrastructure.

Industrial Composting Facilities

In the US, fewer than 200 industrial composting facilities accept compostable plastics, and many are concentrated in California, Colorado, and the Northeast. These facilities require proper sorting and collection of organic waste. If compostable packaging ends up in a landfill, it may become anaerobic and generate methane, a potent greenhouse gas. Some newer landfill technologies capture methane for energy, but the packaging itself won’t compost meaningfully.

Home Composting

Home composting is more accessible for uncoated paper, yard waste, and certified home‑compostable plastics (e.g., those with OK Compost HOME). However, even home‑compostable materials require careful management of temperature, moisture, and aeration. Many consumers may not have the time or space to maintain an active compost pile.

Recycling Contamination

Compostable plastics are generally not recyclable in traditional plastic recycling streams because their chemical composition differs from conventional plastics. If they enter a recycling facility, they can contaminate the batch, reducing the quality of the recycled resin. Clear labeling is essential to prevent this misrouting.

Biodegradable Plastics in the Ocean

The term “biodegradable” does not guarantee that a product will break down in marine environments. Even PLA, which is compostable on land, will not biodegrade in cold ocean water. Only a few materials, such as PHA, have demonstrated marine biodegradability under standardized tests (ASTM D6691). Products labeled as biodegradable may still persist in the ocean for decades.

Given these infrastructure gaps, the most environmentally responsible choice is often to reduce packaging altogether, reuse containers, or select materials that are widely recyclable (e.g., aluminum, glass, PET) in your region. For a deeper look at US composting infrastructure, refer to the EPA’s guide to sustainable management of food and organic waste.

Choosing the Right Packaging for Your Business

Selecting between compostable and biodegradable options requires a multi‑factor analysis. Here is a framework to guide decision‑making.

1. Product Shelf Life and Barrier Needs

If your product has a long shelf life (over six months) or requires a high moisture barrier (e.g., coffee beans, dry snacks), compostable films may not yet match the performance of conventional plastics. Some newer laminates using EVOH (ethylene vinyl alcohol) coatings are compostable but are still expensive and limited in supply. In such cases, biodegradable options like paper with a water‑based coating might be more practical.

2. Target Disposal Pathway

Analyze where your customers will dispose of the packaging. If you sell in cities with strong organics collection programs (e.g., San Francisco, Seattle, many European municipalities), compostable packaging is a good fit. If your market lacks industrial composting, a recyclable material (like corrugated cardboard) or a reusable system may be better. For takeaway food, fiber‑based clamshells that are both recyclable and compostable (if clean) can work.

3. Regulatory Compliance

Many jurisdictions are tightening rules on single‑use plastics. In the EU, the Single‑Use Plastics Directive bans certain plastic products and requires clear labeling on compostable items. In Canada, single‑use plastic restrictions are expanding. The US lacks a federal ban, but states like California, New York, and Washington have enacted laws that affect packaging choices. Stay current with local regulations to avoid fines and ensure market access.

4. Certification and Supplier Audit

Only source packaging that carries a recognized certification (BPI, DIN CERTCO, etc.). Ask suppliers for test reports and engage third‑party verification if necessary. Avoid generic “eco‑friendly” or “green” claims without proof. Consider using the ASTM D6400 standard as a reference point in your procurement specifications.

5. Cost and Volume

Compostable packaging typically costs 20%–50% more than conventional alternatives. Biodegradable (non‑compostable) options may be slightly cheaper but carry reputational risk if they are later found to be misleading. For high‑volume items, negotiate long‑term contracts with manufacturers to reduce premiums. Also consider that improved lifecycle messaging can enhance brand loyalty, offsetting higher upfront costs.

The packaging industry is rapidly evolving due to consumer pressure, regulatory shifts, and material science breakthroughs. Key trends include:

  • PHA Scale‑Up: Polyhydroxyalkanoates can biodegrade in various environments, including marine and soil, without requiring industrial heat. Companies like Danimer Scientific and Full Cycle Bioplastics are scaling production, though costs remain high.
  • Advanced Bio‑Coatings: Water‑based and bio‑based barrier coatings (e.g., from shellac, chitosan, or proteins) are replacing polyethylene coatings on paper. These coatings are compostable and allow paper to remain recyclable.
  • Home‑Compostable Certification Growth: As consumer composting at home increases, more materials are being designed to meet lower‑temperature standards (OK Compost HOME). Expect wider availability of home‑compostable flexible films.
  • Policy to Eliminate Oxo‑Degradables: The EU, UK, and several US states (e.g., California) are banning oxo‑degradable plastics due to microplastic pollution. This will force the market toward true compostable materials or recyclable alternatives.
  • Digital Labeling with Disposal Instructions: Smart packaging with QR codes linking to local disposal guidelines helps consumers correctly sort items. This reduces contamination and improves end‑of‑life outcomes.
  • Chemical Recycling Integration: Some compostable plastics (like PLA) can be chemically recycled back to monomers, offering an alternative end‑of‑life pathway. Facilities for chemical recycling are still rare but expanding.

These trends indicate a shift toward more precise, verifiable claims and away from vague terms like “biodegradable.” For a comprehensive industry outlook, the European Bioplastics Association publishes annual market data.

Conclusion

Compostable and biodegradable packaging are not interchangeable. Compostable packaging offers a clear, certified path to turning waste into soil nutrients, but it requires the right infrastructure and consumer behavior. Biodegradable packaging, while sometimes cheaper, is a murky category that can mislead buyers and cause environmental harm if not properly regulated. The best choice depends on your product’s needs, your market’s disposal capabilities, and the verifiable certifications you can obtain.

To move the industry forward, businesses should prioritize reduction and reuse first, then select certified compostable materials when single‑use is unavoidable, and avoid unsubstantiated biodegradable claims altogether. By demanding transparency and supporting robust composting infrastructure, we can make sustainable packaging a reality rather than a marketing slogan.