How does sustainable parchment paper perform in real baking environments?

Driven by increasing consumer focus on health, hygiene, and at-home cooking, unbleached parchment paper is emerging as a credible alternative to traditional bleached versions. 

However, for manufacturers and product developers, the challenge is clear: how do you transition to more sustainable materials without compromising performance? 

Parchment paper still needs to deliver critical barrier properties, from non-stick functionality and heat resistance to grease protection, durability, and, in many applications, moisture resistance. The key question remains: can unbleached, more sustainable options deliver the same performance under real baking conditions? 

At CPI, we set out to answer that question by evaluating how commercially available unbleached parchment papers behave at typical baking temperatures. The results highlight where sustainable materials are already performing well, and where further optimisation is needed. 

Why the shift towards sustainable parchment paper?

Parchment paper has long been a staple in baking due to its greaseproof, non-stick, and heat-resistant properties. Historically, bleached grades have dominated the market, offering consistent appearance and reliable performance. 

However, increasing scrutiny of chlorine-based bleaching processes, including their environmental impact and potential by-products, is accelerating the transition to unbleached alternatives. At the same time, the industry has moved away from legacy coatings such as PFAS and chromium compounds, with silicone now widely used to deliver non-stick performance. 

Emerging plant-based and bio-polymer coatings are opening up new opportunities for more sustainable solutions. For businesses, this introduces a familiar tension: reformulating materials to meet sustainability goals while still delivering the performance, processability, and compliance required in real-world applications. 

How we tested real-world baking performance

To understand how these materials behave in practice, we evaluated three commercially available parchment papers: a supermarket own-label product, an ethically positioned speciality brand, and a nationally established brand. 

Each sample was tested both as supplied and after exposure to baking temperatures of 180 °C, 200 °C, and 220 °C. Advanced analytical techniques, including optical microscopy, scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy, confirmed that all samples were based on cellulose fibre networks with silicone-based surface treatments. 

To build a complete picture of performance, we combined industry-standard testing with deeper material characterisation. This included grease resistance testing (Kit test), water absorption (Cobb test), and water vapour transmission rate measurements, alongside microscopy and spectroscopy to understand structural and chemical changes. 

This approach enables not just a comparison of performance, but a clearer understanding of why materials behave the way they do – a critical step when refining formulations or preparing for scale-up. 

What happens to parchment paper at baking temperatures?

The first question is straightforward: does parchment paper degrade under baking conditions? And the answer is reassuring. All samples remained thermally stable across the tested range of 180 – 220 °C, with no structural degradation observed. Significant decomposition only occurred at temperatures above 300 °C.

That said, subtle changes did occur. As the temperature increased, the paper darkened due to oxidation. At a microscopic level, this was driven by molecular and structural rearrangements rather than damage to the fibre network. 

In practice, this means the material continues to perform as expected during baking, even as its underlying chemistry evolves. 

Does heat affect strength and durability?

While thermal stability is maintained, mechanical performance does change with temperature. All samples showed reduced puncture resistance as temperature increased, with the most significant drop at 220 °C. Heat exposure also reduced flexibility, making some samples more fragile under repeated handling. 

Performance differences between the samples were clear. The ethically positioned speciality parchment paper showed the strongest mechanical integrity, while the supermarket own-label paper delivered moderate performance. The nationally established brand was the most prone to damage under applied stress. 

For manufacturers, this is where risk begins to emerge. In high-throughput environments or applications involving handling, filling, or transport, reduced strength can translate directly into material failure, product loss, or inefficiencies on the line. 

How does the surface change during baking?

Barrier performance is strongly influenced by surface properties, including roughness and chemistry. We found that moderate heating, between 180 and 200 °C, slightly increased surface roughness. At 220 °C, the surface became smoother due to fibre softening and changes in the coating. 

These shifts influenced how the material interacted with liquids. Moderate temperatures slightly reduced friction, while higher temperatures reduced static friction but increased kinetic friction. These changes are linked to alterations in surface morphology and chemistry, which in turn influence how liquids spread or repel. 

Despite these changes, all samples remained strongly hydrophobic and oleophobic. In practical terms, they continued to repel both water and oil effectively throughout the baking process. 

Can sustainable parchment paper still resist grease?

Grease resistance remains one of the most critical performance requirements for baking parchment. The results showed clear differences between samples. The speciality brand delivered consistently high grease resistance across all temperatures, while the supermarket and established brands improved at 200 °C before declining at 220 °C.

This behaviour is closely linked to surface structure. Increased roughness at intermediate temperatures reduces the contact area between oil and the paper, improving resistance. At higher temperatures, as the surface smooths, grease is able to spread more easily, reducing performance. 

This highlights an important point for product developers: grease resistance is not static. It evolves with temperature and material structure and needs to be understood in the context of real use conditions. 

What about moisture and water resistance?

Moisture interactions play a significant role in baking environments, particularly when steam is present. Interestingly, all samples became more water-resistant as the temperature increased. Water absorption dropped significantly at 220 °C, driven by structural changes within the cellulose fibres. As fibres shrink and densify, pore size is reduced, and pathways for liquid penetration are restricted. Stronger internal bonding within the fibre network further limits water uptake. 

At the same time, water vapour transmission decreased, making the material a more effective moisture barrier during use. For applications exposed to humidity or steam, this represents a functional advantage rather than a limitation. 

What does this mean for sustainable materials?

The overall picture is clear: unbleached, sustainable parchment papers can deliver the performance required for real baking environments. 

However, performance is not uniform. It is highly dependent on formulation and structure. The speciality brand delivered the most consistent performance across all tests, while the supermarket product showed more balanced performance with temperature. The established brand demonstrated the greatest performance improvement with heat, but with the highest variability, 

For businesses, this reinforces a key point. Transitioning to sustainable materials is not a simple substitution. It requires careful validation to ensure performance is maintained across the full range of operating conditions. 

Why this matters for industry

For packaging developers, food manufacturers, and materials innovators, the shift towards sustainability introduces both opportunity and uncertainty. The questions are practical: will the material perform as expected, integrate into existing processes, and meet both regulatory requirements and customer expectations? 

This study shows that performance is governed by a combination of interacting factors, from surface chemistry and structure through to the behaviour of the fibre network itself. Understanding this interplay is essential to reducing risk and accelerating adoption. 

At CPI, we help organisations navigate this complexity, from early-stage material evaluation through to optimisation and scale-up, ensuring that sustainable solutions are not only viable but also commercially robust. 

Let’s innovate together

As demand for sustainable packaging continues to grow, performance remains critical to successful adoption. 

If you’re reformulating materials, developing new packaging solutions, or scaling sustainable innovations, CPI can help you evaluate, optimise, and translate your materials into real-world applications. 

Get in touch to explore how we can support your next project.