worms – Bean Thinking

the cup before the worm bin — “Completely compostable”
But how compostable is it?

So we’re trying to do our bit for the environment and ensure that we always get a compostable cup for our take-away coffee. But have you ever stopped to wonder, just how compostable is compostable?

It is a sad fact that most items that are described as ‘compostable’ do not compost as you or I may expect. Throw a ‘compostable’ cup in a compost bin (or wormery) and you may be surprised at how long it takes to disappear. The reason is that the legal definition of compostable generally refers to industrial composting conditions. In contrast to the worm bin, or the home-compost heap, an industrial composting facility is kept at (58±2)ºC. In these conditions, something defined as ‘compostable’ by the EU regulation EN 13432 or the US based ASTM D6400 needs to have completely disappeared within 6 months but have 90% disintegrated to fragments smaller than 2mm by 12 weeks.

Perhaps it is not hard to see why the legal criteria are defined this way. How would you define common criteria for home composting? Although there is a (Belgian led) certification called “OK compost” by Vinçotte, there are as yet no widely agreed definitions for home composting. However, some companies do try to seek out truly home-compostable packaging. In the case of coffee specifically, one coffee roaster trying to keep their environmental impact to a minimum is the Nottingham based Roasting House. Although most of their packaging is paper, (recycled and recyclable), they needed something less permeable for transporting pre-ground coffee by post. Apparently this took quite a search as many bags that said they were home-compostable turned out not to be. Eventually however they chose Natureflex, a packaging that provided a good moisture and air barrier to protect the coffee but that also broke down in a home composting environment.

But how quickly would it disappear in a worm-composter? On the 6th May 2017 my coffee from Roasting House arrived double packed. First in a Natureflex compostable bag and then in the standard (recyclable) paper bag/envelope. It was ready to be placed in the worm bin on the 8th of May 2017.

See the video below for how long it took to be eaten by the worms:

Seventeen weeks later, on 4th September, it was time to declare the bag composted. After 17 weeks, the bag had started to become indistinguishable from other items in the worm bin (such as garlic skin) and when I picked up what bits seemed to remain, they quickly disintegrated in my hand. It seemed time to declare it over for the bag. A truly home-compostable bag, but how does it compare to the ‘OK Compost’ label of Vinçotte.

Coffee bag genuinely home compostable — How it started.
The Roasting House bag before it went into the worm composter.

The definition used by Vinçotte is not for a worm-composting bin but a standard home-compost heap. Ignoring this fact for the time being, the certification requires that a compostable item disintegrates to pieces less than 2mm within 26 weeks and has fully gone within 365 days when held (in a compost bin) between 20-30ºC. Within these criteria, the packaging from Roasting House is certainly “home compostable” as determined by the worms. Although there were bits of greater than 2mm after 17 weeks, just handling them reduced their size to bits in the mm range. And that was only after 17 weeks, well within the 26 specified by the criteria used by Vinçotte.

So now we’re just waiting for the coffee cup. That went into the worm bin on the 20th April 2017 and is still going, 21 weeks later. Will it be home-compostable? Will the lining that’s needed to keep the coffee from leaking out prevent the worms from breaking it down? You’ll find out here! Make sure you sign up to the BeanThinking newsletter or follow @thinking_bean on Twitter or Facebook to be one of the first to find out when the coffee cup has finally gone.

In the meanwhile, if you’re looking for an environmental solution to your take-away coffee cup habit, it is worth investing in a re-usable cup. Most councils at the moment do not provide industrial composting facilities. Moreover, it is not safe to assume that compostable items will eventually compost in a landfill as modern landfills are water-tight and air-tight. As they say here, the modern land fill is not designed to mulch as much as to mummify. So,if you want to avoid green-washing, you may want to invest in a re-usable cup, for a review of these see Brian’s coffee spot here.

coffee ground, grind, composting — What do you do with your used coffee grounds?

What do you do with your finished coffee grounds? Feed them straight to the plants? Donate them to Biobean to be transformed into fuel? Or perhaps turn them into compost with a worm bin? Ground to Ground is a website dedicated to sharing information about what can be done with old grounds. My preferred option though is the worm bin. Each Chemex of coffee grounds gets put out into the “can-o-worms” compost bin ready to be transformed into compost and plant fertiliser.

I had thought that there could be very little connection between my worms (so to speak) and the Bean Thinking website. However, I recently came across an anecdote about Charles Darwin that, to me at least, unites some of what Bean Thinking is about with my can-o-worms.

can-o-worms, worms, coffee grounds, composting — The top layer of my worm bin. You can just see some coffee grounds but it is mostly cabbage.

Darwin’s last book was “The formation of vegetable mould through the action of worms” published in 1881. After Darwin’s death (in 1882), Edward Aveling (1849-1898) wrote about meeting Darwin years earlier. In “Charles Darwin and Karl Marx: A Comparison” (1897), Aveling wrote: “I remember, in my youthful ignorance, asking Darwin why he dealt with animals so insignificant as worms. I shall not forget his reply, or the look that accompanied it. ‘I have been studying their habits for forty years’.”

By studying what to others looks insignificant, Darwin had made huge progress in our understanding of worm behaviour. This has led to our current knowledge about the contribution of worms to the ecosystem and the benefits of composting our coffee grounds, both for our plants and our planet. It strikes me that we can all benefit from slowing down and noticing what seems insignificant.

Perhaps you do something unusual with your old coffee grounds? Maybe you have noticed something about coffee grounds and worm behaviour. Whatever it is, do let me know in the comments section below.