Tales from the worm bin

It is hard to believe but it was one year ago this week that the composting experiment that became #willitcompost started. The idea was to test just how “compostable” a coffee cup described as “completely compostable” really was. The problem is that “compostable” has a legal definition but it is not one that you or I may immediately recognise. Legally for a take-away coffee cup to be described as compostable it has to completely disappear within 6 months in an industrial composting facility. Industrial composting is quite different from home composting. In the former, the temperature is kept at (58±2)ºC while in my composting worm bin, it can get very cold indeed.

As has been written about elsewhere, in the absence of better industrial composting facilities, there is very little virtue involved by swapping a disposable cup for a compostable one, to combat the problem of waste it would be far better to remember your re-usable. However, what if you had a composting bin at home? How long would it take the cup to compost? And even, would it compost?

So every week for the past 52 weeks, I have posted a photo of the cup, composting away, in the worm bin. It seems clear that although it will eventually compost, more than 52 weeks is a long time to wait and not practical if you are drinking multiple take-away coffees.

In the meanwhile, other questions have been raised. What about other coffee packaging such as the bags for roasted coffee beans? What about the compostable “glasses”? Can anything be done to speed up the composting of the cup?

Last month, the opportunity came to start a new experiment testing these questions. A compostable coffee roasting bag from Amoret Coffee (which was reviewed on Bean Thinking here) was placed in the second shelf of the worm bin together with a cup, a compostable “glass” and a section of food packaging. The cup and the ‘glass’ were cut in half before being placed in the worm bin. One half of each was left as it was but the other half was soaked in (initially boiling) water for 12 hours. The idea of this was that part of the problem that has slowed the composting of the original cup was the lining that is designed to hold hot liquids without leaking. If we could somehow weaken that lining before placing it in the worm bin, perhaps the composting process would be accelerated?

Starting in late March provides the best chance of a quick composting process due to a particular aspect of worm behaviour. Although the composting worms will continue to eat the waste put into the composting bin throughout the winter, they do slow down quite a lot. If you have a worm bin, you may notice that the amount of waste that you can put into the bin decreases during the winter months. On the other hand, as the weather improves, the worms seem to eat everything very quickly so, to provide the best conditions for composting, the weather has to be reliably warm (or at least, not freezing).

Rather than once a week, updates will be approximately once per month both on social media and in the Bean Thinking newsletter. So keep your eyes on #talesfromthewormbin on twitter or subscribe to the newsletter. Do we really take our environmental responsibility seriously by using compostable packaging or, ultimately, is a more radical approach to waste, single use packaging and consumerism necessary?