PwC Study: Is Cork the More Sustainable Choice?

When we talk about environmentally responsible materials, terms such as “green”, “eco-friendly” or “sustainable” are often used very broadly. Life cycle assessments provide a more objective approach by looking at the environmental impact of a product across different stages of its life.

A PwC life cycle assessment compared three types of wine closures: natural cork, aluminium and plastic. The study looked at a functional unit of 1,000 closures used for standard wine bottles sold on the UK market.

What did the PwC study find?

The results are striking. Across the environmental indicators assessed, cork closures performed better than aluminium and plastic in most categories.

For greenhouse gas emissions, the study calculated approximately 1.5 kg CO₂ equivalent per 1,000 cork closures, compared with around 14.8 kg for plastic closures and 37.2 kg for aluminium closures.

In other words, within this specific application, plastic closures generated almost ten times and aluminium closures around 24 times the greenhouse gas emissions of natural cork closures.

Cork also performed best in the study for non-renewable energy consumption, atmospheric acidification, photochemical oxidant formation, eutrophication and solid waste generation. Aluminium performed better for water consumption.

Does cork have a negative carbon footprint?

This requires a little more precision.

Cork oak forests absorb CO₂ as the trees grow, and the bark can be harvested repeatedly without cutting down the tree. The PwC study also considered carbon sequestration associated with cork forestry in its sensitivity analyses.

However, the main results of the study do not show a negative overall carbon footprint for the complete cork closure life cycle. They show something different, but still significant: among the three wine-closure systems studied, cork had by far the lowest greenhouse gas emissions.

That distinction matters. Environmental performance always depends on the specific product, the amount of material used, production methods, transport, lifespan and what happens at the end of its life.

From wine closures to other cork products

The PwC study focused specifically on wine closures. Its numerical results therefore cannot simply be transferred to flooring, insulation, fashion products or packaging.

What the study does demonstrate is the potential of cork as a material. Cork is harvested from the bark of the cork oak without felling the tree, and the bark regenerates over time. The material is lightweight, durable and can be used in a wide variety of applications.

Whether cork improves the environmental footprint of a particular product must ultimately be assessed for that specific application.

Why Biork uses cork

For Biork, cork is not simply decorative packaging. The cork casing protects the mineral deodorant stone, acts as its holder and remains part of the product throughout its useful life.

This allows Biork to avoid a conventional plastic deodorant container and additional retail packaging. The mineral stone itself can last for many months with normal use, and the cork holder can later be reused with a refill stone.

Biork therefore combines three very concrete characteristics:

• a cork casing instead of a conventional plastic deodorant container

• no additional retail box

• a long-lasting mineral deodorant stone with a refill option

Rather than describing the product with broad environmental promises, these are the characteristics that make the Biork concept different.

Conclusion

The PwC study provides strong evidence for the environmental performance of natural cork wine closures compared with aluminium and plastic closures. In the study, cork produced substantially lower greenhouse gas emissions and performed best in six of the seven environmental indicators assessed.

That does not mean that every cork product automatically has the same environmental footprint. But it does show why cork is such an interesting material when it is used intelligently.

At Biork, that means using cork as a durable part of the product itself: protecting the deodorant stone, replacing a conventional plastic container and making additional retail packaging unnecessary.

Source: PwC / Ecobilan, Analysis of the Life Cycle of Cork, Aluminium and Plastic Wine Closures, 2008.