Are you a glass bottle half-full or aluminum can half-empty person? We’ve set up a head-to-head battle to learn which container is better for the planet. So grab your soda or beer, and let’s see which serves up the most environmental pints, er, points.

Creating a can vs. building a bottle

Aluminum comes from a red sedimentary rock called bauxite. No bauxite is mined in North America, so we import it from open-pit mining operations in countries like Brazil, Jamaica, and Guinea. In 2018, Human Rights Watch warned that bauxite mining in Guinea has had “profound human rights consequences,” as some mining companies take ancestral land from rural farmers, damage local water sources, and pollute the air.

“Mining bauxite requires substantial — not just land-scarring — but also a significant amount of energy,” says Nemkumar Banthia, a University of British Columbia professor and senior Canada research chair in infrastructure, rehabilitation, and sustainability. Banthia echoed the findings of a 2008 Slate article, which found that “manufacturing a 12-ounce aluminum can is twice as energy-intensive as making a similarly sized glass bottle.”

After mining, a chemical process extracts aluminum oxide from the rock in powder form. That powder is smelted into metal using electricity and heat, and then factories convert aluminum sheets into products from car parts to beer cans. Making a can from recycled aluminum requires only 8–10% of the energy needed for new aluminum.

Glass, on the other hand, is made by melting down widely available materials like silica, sand, soda ash, and limestone in high-temperature furnaces. Silica is everywhere, says Banthia: “It’s one of the most abundant materials of the Earth’s crust.”

Manufacturing a 12-ounce aluminum can is twice as energy-intensive as making a similarly sized glass bottle.

According to the US Energy Information Administration, glass manufacturing is also one of the “most energy-intensive industries.” Bottles made from recycled glass take about 70% of the energy needed to make new glass, as glass melts at a lower temperature than its raw materials.

Despite the energy needed to make glass, new aluminum requires even more when you consider bauxite mining’s impact. This round, we’re pouring points into glass.

Promising empties

Both aluminum and glass are infinitely recyclable, meaning they can be broken down and remade repeatedly without losing strength. And because aluminum is practically unbreakable, the number of times it can be recycled really is infinite; broken bottles unfortunately end up in the landfill.

It’s hard to know how much is actually recycled, though, says Clarissa Morawski, whose Barcelona-based company CM Consulting does waste-reduction and recycling analysis for industry and government. Not all jurisdictions publish data, and each has different recycling and reporting systems, says Morawski, who has studied waste-reduction policies for over 20 years. For 2019, Morawski says CM’s best estimate for aluminum can recycling in Canada was 70%. Estimates for what percentage of the average new can is made from recycled aluminum range from 40% to 70%.

Across Canada, non-refillable glass beverage recycling rates range from 66% in Newfoundland and close to 90% or higher in BC, Alberta, and Nova Scotia, according to a 2018 analysis by CM Consulting. In the US, states with beverage deposit programs have an average glass container recycling rate of 60%, while non-deposit states only reach about 24%, according to the Container Recycling Institute.

Unlike cans, some glass bottles have another possible fate: reuse. In Canada, refillable beer bottles are used by big breweries with infrastructure to sanitize them, like Sleemans, Molson, and Labatt. Canadians could be drinking out of the same bottle they returned as little as 30 days ago, thanks to programs that collect beer bottles brought to depots and return them to beer companies. “With a national collection rate of approximately 95%, the refillable beer bottle is Canada’s most recovered beverage container,” according to CM Consulting’s 2018 report.

In Germany, glass bottles are reused up to 50 times.

In Canada, refillable beer bottles are typically used up to 15 times before they’re recycled. But other places do way better. In Germany, glass bottles are reused up to 50 times. “Germany has probably the highest market share for refillable bottles for beer in the world,” says Morawski. She says many life-cycle assessments have found that the refillable glass bottle is, “the most ecologically friendly” container for beer.

Oregonians are closing in on Germany’s re-use rate. Founded in 2018, the Oregon Beverage Recycling Cooperative (OBRC) is the first state-wide refillable glass bottle program in the US. The OBRC handles bottle collection, washing, and re-distribution among ten different breweries. In 2019, they had over 400,000 bottles in circulation that can be refilled up to 40 times.

Henry Pedro at Nova Scotia’s Boxing Rock Brewing has blogged about why his craft brewery uses them: “refillable 341 mL bottles are durable, practical and reusable and that’s important to us.” At the beer store, he says, look for ratty bottles, which have gone through the system a few times.

Think of those dusty-looking scratches as an “environmental halo,” jokes Morawski.

Since Pedro’s 2017 post, Boxing Rock has started filling some aluminum cans to please consumers and retailers who find them more convenient. In line with their values, they use cans with logos printed on them rather than plastic sleeves, and buy from a manufacturer that says they use about 60% recycled aluminum.

But perhaps the ultimate refillable beer container is the growler — a glass jug that some craft breweries will fill directly from their taps. Made of thick glass, well-cared-for growlers can survive many, many refills.

For this round, both cans and bottles get points for being infinitely recyclable, but glass gets a few extra points for its potential reusability.

Secondary packaging thoughts

Six-pack rings have become a symbol of plastic waste and harm to wildlife. Some companies are experimenting with biodegradable and compostable alternatives — and even glue — but plastic rings still turn up in our oceans and landfills.

In Vancouver, Humblebee Meadery co-founder Pierre Vacheresse calls them “turtle-killing rings.” Instead, Humblebee uses reusable harder plastic can-carriers made out of recycled materials for its secondary packaging. Vacheresse collects them for reuse from liquor stores once they’ve removed cans for individual sale.

Multi-packs of glass bottles are usually transported in cardboard boxes. While paper is recyclable, it’s important to remember that making paper is also a water-, energy-, and chemical-intensive process. As a whole it accounts for 4% of global energy use.

What about branding? Aluminum cans and glass bottles sometimes come with labels or sleeves, which can contaminate the recycling stream. Logos or designs painted directly on the surface make recycling easier.

With the historic and ongoing plastic pollution from a can’s six-pack rings, we’re giving this round to the glass bottle.

Emissions en route

Aluminum and raw materials for glass are transported to factories that make containers, which go on to breweries that fill them, businesses that sell them, and (hopefully) recycling facilities and back again — in trucks and vans that spew carbon the whole way. Aluminum wins this round for being light-weight and easy to stack, making it easier to transport more with fewer trips.

The winner: refillable glass bottle

Overall, the refillable glass bottle wins, with an aluminum can made of mostly recycled aluminum as the runner-up. The challenge is, it’s extremely difficult to find out what percentage of a can is made of recycled aluminum.

Your best option? Bike to a nearby micro-brewery or kombucha bar and fill up your growler: the ultimate refillable glass bottle.