‘Whereas salt and sunlight can cause plastics physically to break apart into smaller pieces, chemically the hydrocarbons linked together into the polymer chains of which plastics are made do not spontaneously decompose into other compounds. Like crude oil, from which most polymers are derived, that happens only if they are burned at a high temperature to release mainly carbon dioxide and water. In normal conditions plastic simply accumulates in the environment, much as carbon dioxide does in the atmosphere, (‘Too much of a good thing’, The Economist March 3rd 2018, p50).
Dr Ron Jackson (Wine Report, 2008) says plastic bottles or PET are made from polyethylene terephthalate, the same material that is called polyester when spun into cloth. PET bottles require less energy than glass bottles during fabrication, are less breakable, are lighter to transport, can easily be coloured to specification and are more easily recycled [although see directly below]. For plastic bottles and cartons the most common types are PET (type 1) and HDPE (type 2). Plastics are made from fossil fuels. They are flexible, lightweight and can be shaped into any form. But there are many different types which must be processed separately for recycling. Plastic is often down-cycled into products such as plastic lumber (used in place of wood), drain pipes and carpet fibres – which tend to end up in landfills eventually, Jackson concludes
The disadvantage of plastic bottles depends on what they are lined with because as they are not inert wine can start to taste of the package itself after only a few months (Oxford Companion to Wine 4th edition. p565).
Recycling biodegradable plastic
‘Making plastics biodegradable, by adding corn starch or vegetable oil to petroleum-derived hydrocarbons, renders them harder to recycle. Recyclers already struggle to invest in capacity or innovation even in countries that collect lots of their rubbish. Periodic declines in the oil price, which makes virgin plastic cheaper, can bankrupt recyclers, many of which are small or medium-sized companies, says Peter Borkey of the OECD, a rich-country think-tank,’ (‘Too much of a good thing’, The Economist March 3rd 2018, p51).
Dr Ron Jackson in Wine Report 2008 ed. Tom Stevenson (Dorling Kindersley, 2007), p391.
The Oxford Companion to Wine 4th edition ed. Jancis Robinson MW and Julia Harding MW (Oxford University Press, 2015), p565.