It was a long, cold winter in the Northeast, but after several months of my compost just freezing in situ over the last 30 days or so, my food and other biodegradable materials have been breaking down again and I have a serious pile of dark brown soil to throw in my garden beds! Part of that compost is made up of materials I have tested out for this column - plenty of Whole Foods takeaway containers, Bambu plates, and more - but unfortunately, a corn cup I used for wine at a party last August has not found the same end. After seven-plus months in my compost heap (with a few of those months frozen solid, I'll admit!), it has not biodegraded one bit, which was a disappointment after my previous successes. When I did some checking, I found that the cup, which is made from corn, is only meant to degrade in a commercial compost system.
I went to the website for the cups, which are made by Natureworks, and my initial frustration with the fact that the cup hadn’t broken down was allayed a bit by what is clearly quite a bit of thinking about how to make a sustainable, disposable product (hmm, I wish that was actually an oxymoron in our society).
But should we be using foods — which could be eaten by hungry people or even less hungry but still food-creating cows — to make packaging (or even fuel), considering the energy needed to grow those crops (mostly petroleum-based energy) in the first place? It seems wasteful, and that there should be a better way, so I did some digging: how green are these cups really?
The cup, about a month after it was added to the compost bin in my backyard.
As the Natureworks Ingeo (the brand name for the plastic the cup is made from) site states in its very comprehensive page on the material content, these cups are not made from oil: “If you replace the PET in 100,000 plastic food containers with Ingeo, you can save greenhouse gas emissions equal to driving a car 16,000 miles and an amount of non-renewable energy equal to 19 barrels of oil or 775 gallons of gasoline.” They also use only a very small percentage of the world’s corn, so at this point, they don’t affect food prices. And it’s not corn that the cups are really made of — it’s the sugar from corn; we only need a sugar source. This could include sugar beets, sugar cane, wheat and more.
Moreover, the company says that in the future, “Ingeo will be made from cellulosic raw materials, agricultural wastes and non-food plants.” Ingeo’s overall life cycle analysis is better than plastic cups, but higher than paper (though according to their data, this will change with new materials that are coming next).
The still-intact corn cup, almost seven months after first being placed in my compost bin.
In the case of biodegradability, only a commercial system will break this cup down. Commercial composting gets much hotter inside the compost unit than in my pile out back, which in the case of the Ingeo cups (PLA), breaks them down toute de suite. But with only 413 of those in the country, the most likely place this cup will end up will be in a landfill where it won’t degrade either. (To be fair, almost nothing degrades in a landfill, even newspaper and plenty of food, as there’s not enough oxygen in these systems for the bacteria and other breakdown organisms to do their work.)
I do like the fact that these cups look and feel like regular plastic drink cups; that’s important for acceptance, and it’s clear that tons of thought went into the entire lifecycle of this product. And yes, they are still better than plastic cups, even if that plastic is recycled (and most isn’t). But when I get a piece of packaging that says it will biodegrade, I expect it to turn to dirt for my garden — otherwise it needs another label.
Starre Vartan is founder and editor-in-chief of Eco-Chick and author of The Eco-Chick Guide to Life (St. Martin’s Press). A green living expert, she contributes to The Huffington Post and Mother Nature Network (MNN.com)