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I was absolutely horrified when I saw the new Backsberg “Tread Lightly” in a supermarket recently. I mean we’re still trying to get our heads around cork versus screw cap, now the wine industry is throwing another curve ball at us: Polyethylene terephthalate aka PET bottles. Or just call it plastic if you prefer. Why on earth would they use plastic bottles and what are the consequences for wine quality?
This is a tricky one, because it seems like the main drive behind the new packaging is that plastic bottles are more environmentally friendly than their glass counterparts. The first advantage of PET bottles is that a plastic bottle weighs only 50g compared to an average glass bottle which weighs about 400g.

Secondly, transport seems to be more effective. As the bottles are smaller, you can stack an extra 36% in a container when you export. This means more effective transport, less fuel and less carbon emission.

Thirdly, PET bottles are more robust, as plastic is less likely to break when man-handled. This makes it ideal for an outdoor lifestyle that involves picnics, rafting, camping and hiking.

Lastly, it is actually more environmentally friendly to manufacture and recycle plastic bottles. I know this is a difficult one to get your head around. I always thought that plastic was the original Prime Evil, polluting oceans and hindering recycling. It seems like glass is even worse, whether you’re talking manufacturing or recycling. “Reports in the public domain record reductions in CO2 emissions from as low as 29% to as high as 52% when using PET as opposed to glass, and energy consumption in the manufacture and supply chain is reduced by 40 to 50%”.

So there you have it: plastic bottles are more eco-friendly and they can be recycled to produce things like polar fleece. Which means you can drink a bottle of wine and then recycle it to knit a jersey.

Next question: What are the implications from a wine quality point of view?

The biggest criticism against PET is oxygen permeability.  Plastic is not particularly good at keeping oxygen out, which means the wine will oxidise a lot quicker in PET bottles, limiting the lifespan of wines in plastic. It seems like Mondi, the leading supplier of PET bottles in South Africa, has taken extra care of this, trying to build in a special barrier to protect the wine. Unfortunately these “barriers” lose their effectiveness at higher temperatures, which is one of the reasons why it is inadvisable to ship PET bottles over long distances. This pretty much defies the “extra 36% in a container when you export” advantage, doesn’t it? Back to oxidation: The local manufacturers guarantee a shelf life of two years, while French researchers claim this figure is closer to six months. Given the fact that more than 90% of wines are consumed within 48 hours of purchase, does it really matter?

Another tricky point is the health issue. Rumour has it that certain dodgy chemicals with funny names like phthalates (try and pronounce that!) can be leached from plastics by alcohol and are dangerous to one’s health. Phthalates are endocrine disruptors; they can mess up hormone signalling. Very little is known about this matter and I suppose more research needs to be done before I can make wild allegations like this.

I am sure a lot of people will be sceptical about this change in the wine industry. But so were we when screw caps were introduced just over a decade ago, and now that is widely accepted. The twist is that everyone is carbon crazy at the moment: carbon footprint, carbon credits, etc. PET bottles are supported by the Waste Resources and Action Programme (WRAP), a government-sponsored initiative in the UK. Even though we are not at that point in South Africa, the principle is still the same and companies, big or small, are concerned about their impact on the environment.

So, I am sorry for traditionalists like myself but, even though the top end will stick to glass, it seems for supermarket convenience and an easy drinking lifestyle with a feel-good green halo, we will probably see more wine in plastic bottles in the near future.

Boela Gerber is the winemaker of Groot Constantia wine estate in South Africa. This blog was originally posted on

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