What Does 'Compostable' Actually Mean for Paper Cups? EN 13432, OK Compost, and What Buyers Need to Know

Walk through any specialty coffee shop or zero-waste event and you'll see cups labelled "compostable." But what does that actually mean — and does it matter where you're selling?

The short answer: it depends entirely on which standard the cup is certified to, and whether your market has the infrastructure to process it. This guide cuts through the marketing language and explains what buyers need to verify before making a claim.

The Core Problem: "Compostable" Is Not a Single Standard

A cup described as "compostable" could mean any of the following:

• It meets EN 13432 (the European industrial composting standard)
• It meets ASTM D6400 (the US equivalent)
• It carries OK Compost INDUSTRIAL certification from TÜV Austria
• It carries OK Compost HOME certification (a much stricter standard)
• It has no third-party certification at all — just a marketing claim

Each of these represents a very different product and a very different end-of-life outcome.

EN 13432 — The European Benchmark

EN 13432 is the European standard for packaging recoverable through composting and biodegradation. To pass, a material must:

• Biodegrade at least 90% within 6 months under industrial composting conditions (58°C, controlled humidity)
• Disintegrate so that less than 10% of the original dry mass remains after 12 weeks
• Leave no harmful residues (heavy metals, ecotoxicity tests)

This is an industrial composting standard. It does not mean the cup will break down in your garden compost bin or in a landfill. It requires a certified industrial composting facility operating at high temperatures.

OK Compost INDUSTRIAL vs OK Compost HOME

TÜV Austria's OK Compost certification scheme is the most widely recognised third-party mark in Europe. There are two tiers:

OK Compost INDUSTRIAL

Equivalent to EN 13432. The cup biodegrades under industrial composting conditions (high temperature, controlled environment). This is the standard most PLA-coated paper cups meet.

OK Compost HOME

A significantly stricter standard. The cup must biodegrade at ambient temperatures (20–30°C) without any industrial processing — meaning it can go in a home compost bin alongside food scraps. Very few paper cups currently meet this standard, as PLA does not break down at ambient temperatures. Cups meeting OK Compost HOME are typically made with alternative biopolymer coatings.

ASTM D6400 — The US Standard

In the United States, ASTM D6400 is the equivalent of EN 13432 for industrial compostability. Products certified to this standard can carry the Biodegradable Products Institute (BPI) compostable logo, which is required by many US municipal composting programs.

What Documentation Should Buyers Request?

If you are purchasing compostable cups and plan to make sustainability claims to your customers, request the following from your supplier:

1. Certificate number and issuing body — e.g., "OK Compost INDUSTRIAL, certificate no. S0123, issued by TÜV Austria"
2. Certificate validity date — certifications expire and must be renewed
3. Scope of certification — confirm it covers the specific cup size and coating you are ordering, not just the coating material in isolation
4. Test reports — EN 13432 or ASTM D6400 test results from an accredited laboratory

The Infrastructure Problem

Even a fully certified EN 13432 cup is only composted if it ends up in an industrial composting facility. In practice:

• In Germany, the Netherlands, and Scandinavia, organic waste collection is widespread and industrial composting is accessible.
• In the UK, composting infrastructure varies significantly by local authority.
• In the US, only a minority of municipalities have industrial composting programs that accept certified compostable packaging.
• In most of Southeast Asia, industrial composting infrastructure is limited.

If your cups are sold in a market without industrial composting access, a PLA-coated cup certified to EN 13432 will likely end up in landfill — where it will not biodegrade meaningfully. In this context, a recyclable aqueous-coated cup may have a better real-world environmental outcome.

Key Takeaways for Buyers

• Always ask for the specific certification standard and certificate number — not just the word "compostable"
• Distinguish between INDUSTRIAL and HOME compostable — they are not interchangeable
• Match the certification to your market's waste infrastructure
• Request documentation before making compostability claims to your own customers
• Consider aqueous-coated cups if your market has strong paper recycling but limited composting