Vin in a tin: Is wine more sustainable in a can or a bottle?

A new shopping dilemma for me this summer was over buying wine in cans or bottles.

While fizzy drinks, beer and a whole slew of RTDs in bright colours have been sold in cans for a long time, fine wine is traditionally associated with classy bottles. (Let's not even talk about cask or boxed wine – that's a conversation for another day!)

It seems 2023 is the year of wine in a can. With the trend on the rise internationally, a handful of New Zealand wineries are now also selling quality wines in beautifully designed cans.

In the UK, Waitrose is dropping most non-bubbly wine bottles, switching 187ml wine bottles to a range of aluminium cans. The move is tipped to save more than 300 tonnes of glass packaging, halving the carbon footprint per drink due to savings in transportation and storage.

READ MORE: * Is recycled always better for the climate than brand new? * Taking NZ wine carbon neutral to lure younger buyers * Council staff to rifle through recycling in bid to improve waste collection

There's a lot to like about cans. They’re light to carry, easy to chill and almost impossible to break. Crucially, it's also so much easier to dance with a can – rather than a glass – in your hand, without sloshing your pinot noir over your white summer dress.

Then again, wine bottles have classic charm and there's that certain magic to the sound when you pour your first glass.

A standard measure of wine in New Zealand is between 90-110ml, with the typical wine bottle containing 750ml. With wine can sizes ranging from 250-330ml, they’re not exactly single serves, but enough for several glasses. So there's potentially less risk of overindulging because you’re "just finishing the bottle off".

To get a handle on which might be the more sustainable choice, we need to consider the different life stages of each wine vessel.

Glass is mainly made from natural ingredients including silica sand, soda ash and limestone. The raw materials are abundant and easy to access. But high temperatures – requiring a lot of energy – are needed to create it.

Aluminium is produced from bauxite, a clay-like ore that is mined overseas which can create negative environmental and social impacts. Making aluminium from raw materials also requires massive amounts of energy.

Another consideration is how the energy used in that process is generated. For instance, if a glass furnace is fired with fossil gas while an aluminium smelter uses mainly renewable energy, the aluminium's carbon footprint becomes smaller. Complicating things, a lot of aluminium used for cans, as well as the glass bottles we buy in New Zealand -- are imported.

A can weighs a lot less than a glass bottle for the same amount of wine. Cans are also easier to stack together and package, so you can get more of them into one truck or container. That means that the carbon footprint of transporting wine in a can is a lot smaller than from a bottle. But it also depends on our choices: making local, sustainably-run wineries worth seeking out.

Fun fact: The necks of glass bottles means there's "wasted' air" when they're transported.

As a country, we are a bit rubbish at recycling. A 2020 waste audit by waste industry body WasteMINZ found that 69% of our glass gets recycled, while 31% ends up in a landfill. For aluminium, it's even worse. Only 63% is recycled and 37% will spend the rest of its life in a dump. Hopefully this is set to change with the government's plans to introduce a container return scheme from 2025.

Both glass and aluminium can be recycled over and over, and that's where our can wins points over glass.

To recycle glass, used bottles are transported to Visy in Auckland, New Zealand's only glass recycling business. So if you’ve just finished your bottle of pinot noir in Gore, your bottle will rack up a carbon footprint on its journey to the recycling facility. To turn the shreds into recycled new glass bottles, furnaces must reach at least 1500C – and in Auckland, that's currently still fuelled by fossil gas, adding to its carbon footprint. Making new glass and recycling glass almost uses the same energy. Glass is said to be the largest single emitter of greenhouse gas emissions in Auckland.

Your used can also has to return to Auckland to be recycled, but scrunched up it's easier to transport. According to Packaging New Zealand, recycling aluminium requires only 5% of the energy and therefore produces only 5% of the CO2 emissions required to make it in the first place.

The amount of recycled material in cans and glass bottles can vary quite a bit, but as aluminium's recycling process uses significantly less energy, a recycled can practically always win over a recycled bottle.

When it comes to manufacturing, glass is generally the winner. On transportation and recycling, cans come out tops. To get the benefits of either, it all depends on recycling.

Overall, recycled cans are our most sustainable choice.

To be fair not every wine is suitable for this kind of packaging, but the next time you’re shopping for a tipple, consider giving canned wine a chance.

Have a sustainability dilemma? Drop us a line: [email protected] and we’ll try to help you find some answers.