Roasting House

How compostable is compostable?

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.

 

 

Good news on coffee bag recycling & re-using air valves

air valve, plastic, environmental coffee packaging

Air valves and metallised plastic are common packaging materials for freshly roasted coffee.

Hopefully we’re all trying to reduce our environmental impact but there are things that we can’t seem to avoid. There is the saying “reduce-reuse-recycle”, but how do we do that with coffee bags? Can we reduce? How would we reuse? And recycling has, until now, seemed impossible.

The problem is that in order to keep freshly roasted (and particularly freshly ground) coffee fresh, it is packed in metallised plastic bags normally with an air valve. Metallised plastic is not recyclable in the general waste stream and so the air valve, even if it is made of a technically recyclable plastic material, is unlikely to be practically recycled.

There are questions as to whether it is necessary to package coffee in this way. A blind taste test by the Nottingham based coffee roaster Roasting House showed that, if your coffee was freshly roasted, a (recycled and recyclable) paper bag was a good option for packaging. Although the flavour profile was different for coffee stored in a bag with an air valve compared with the paper bag after 1 week of storage, the benefit to the taste did not seem to be worth the environmental cost if the coffee is delivered fresh to the customer (within 24 hours or so).

However, perhaps the roaster that you buy coffee from prefers to use the traditional metallised bags with air valves. What can be done there? Fortunately, there has recently been some great news on this front. Has Bean coffee have teamed up with TerraCycle to offer recycling of Has Bean coffee bags. TerraCycle are a company that specialise in recycling (or reusing or up-cycling) hard to recycle materials, such as coffee bags and coffee capsules. TerraCycle takes materials such as coffee bags and either repurposes them (TerraCycle’s website mentions repurposing juice pouches by sewing them together to make rucksacks) or pelletising them to be made into other plastic products.

Earth from space, South America, coffee

Our common home. Can we keep our coffee habit while keeping our home safe for future generations?
The Blue Marble, Credit, NASA: Image created by Reto Stockli with the help of Alan Nelson, under the leadership of Fritz Hasler

Sadly (but understandably), to take advantage of Has Bean’s offer to recycle your coffee bags you have to be a Has Bean customer. However, all is not lost. If you are not a Has Bean customer you can purchase your own recycling box from TerraCycle for coffee bags (prices start from £73*) or coffee capsules (prices start from £72.36*). Perhaps it is something out of the range of the general consumer but it may be something that smallish coffee roasters with a network of cafés could consider stocking? Do you regularly buy your coffee from a cafe? Why not ask them if they will consider TerraCycle? If you drink coffee from larger companies such as, Tassimo, L’OR and Kenco, there are (free) collection points for their packaging nationwide.

However, what if you don’t buy coffee from either Roasting House or Has Bean nor have easy access to a TerraCycle recycling box? There is one more option in the 3-r’s: re-use. To consider this question, I’ve been experimenting recently with a coffee bag with an air-valve (left over from Roasting House’s experiment that they were happy to send me, thanks Roasting House). Could the air valve be re-used as a valve for fermentation?

Lacto-Fermentation has been in the news a lot recently for the health benefits that it may have. However it is also an interesting and easy way of preserving almost any vegetable. The idea is simple. Mix the vegetables to be preserved in some salt water, store them in a jar and leave them for a few days. That’s it. The salt kills the harmful bacteria while allowing the bacteria that is good for us, the lactobacillus, to thrive. These lactobacillus also produce lactic acid that preserves the vegetables for many weeks while giving them that slightly sour taste of sauerkraut and kimchi.

lacto fermentation, airvalve, air valve, reduce reuse recycle

Can you use coffee bag air valves as one-way lids for fermenting vegetables?

A problem with fermentation seems to be that if you tightly seal the vegetables in a jar, the build up of gas during the fermentation process could mean that the mix explodes. If you open the jar every day to let the gas escape, you may well end up with mouldy cabbage rather than delightfully acidic sauerkraut. This is where the coffee bag air valve comes in. Could you replace the lid with a coffee air-valve and so allow the gas to escape while not having to open the lid every day?

Replacing the glass lid of a Kilner Jar with a lid made from a ring of cardboard (lined with the coffee packaging) and then the coffee bag with air valve seemed to work at first. As had been predicted, my first attempt at fermented spring greens (where I opened the lid each day) had resulted in mouldy cabbage. Successful fermentation came when the glass lid was replaced with the air-valve construction. Could there be a re-use for the air valve?

fermented cabbage

Fermented spring greens. These vegetables have been fermented with salt.

To check whether the valve worked as planned, I used it as a lid for a jar containing bicarbonate of soda and vinegar. As anyone who has played with these substances for making rockets or model volcanoes will know, combining these two substances produces a lot of gas. Again, nothing exploded. However, sadly (?) nothing exploded either when I sealed the air valve with sellotape and repeated the bicarbonate of soda/vinegar experiment. A quick inspection revealed air-gaps between the cardboard ring and the air valve lid and while these could be sealed quite easily, the air valve never seemed to be the primary outlet valve for this set-up.

So, a failure? A null result? Perhaps, but perhaps not. The air valve structure did mean that I was confident that I didn’t have to open the lid on the fermenting cabbage and the cabbage did not turn mouldy before it fermented. Unfortunately, it is hard for me to eat enough fermented cabbage to justify having repeated this experiment enough times yet to be certain! So this is where you come in. Why not have a go at making your own sauerkraut, kimchi or indeed any pickled vegetable (apart from potatoes apparently). Re-use that air valve while reducing food waste. If you do so, please do let me know your design and how it worked (and of course any good fermented vegetable recipes). Alternatively, if you have found another use for those old air valves, or know another coffee roasting company that is recycling its packaging or making efforts to move to  more sustainable packaging, please do let me know in the comment section below, on Twitter or on Facebook.

Enjoy your coffee and your lactobacillus.

*prices correct at time of writing (18th July 2017). Please check TerraCycle’s website for most recent prices. If you are outside the UK, the international website of TerraCycle can be found here.

Coffee bean degassing

coffee, Roast House

Coffee from the Roasting House, one light roasted one dark roasted. They were roasted within an hour of each other.

How long do freshly roasted coffee beans take to  degas? Should you let the beans lose the carbon dioxide inside them for 24h, 72h, one week, more? Do dark roasted beans degas for fewer days than light roasted beans? As readers of Bean Thinking will hopefully know, one of the aims of Bean Thinking is to bring science, and particularly experimental science, onto everybody’s coffee tables. Is there an experiment (or experiments) that you can do to measure the amount, and duration, of degassing with equipment that you will have in your kitchen?

To help me in my coffee bean degassing experiments, I got in contact with the very helpful people at Roasting House. Based in Nottingham (UK) they will deliver freshly roasted beans to you by bicycle if you live in the Nottingham area or, for the rest of us, by Royal Mail. Together with the cycling aspect of their business, they also have a commitment to supporting those people who produce the coffee. It is important I think, not just that coffee tastes good, but that everybody involved in the coffee process (from grower to consumer inclusive) gets a good deal. Lastly, and very importantly for the degassing experiment, Roasting House offer their beans roasted to the degree that you specify. While they helpfully recommend a particular style of roasting for each bean (dark roast for one bean type, a lighter roast for another), they do give you the option of choosing which you would prefer.

They are also very knowledgeable about their coffee. As I was discussing the degassing issue with them, they suggested a coffee (Daterra, Bourbon Yellow) that they thought would degas quite a lot. Not just that, but the coffee concerned would taste great as both a dark and a light roast (I do drink the coffee after all). All in all, this experiment could not have been done without the help and input from Roasting House and I am very grateful to them for their support in my little project. So, onto the experiment.

The Experiment:

water acidification via coffee beans

Red cabbage liquid approx 96h after roasting and then being sealed in a jar with coffee beans. Note the colours.

To discover the time period over which the beans degas, I decided to utilise an effect that (for reasons unconnected to coffee beans) is currently having an alarming environmental effect: the acidification of water by carbon dioxide. Carbon dioxide dissolves in water to form carbonic acid. With the rising atmospheric levels of CO2, this is leading to ocean acidification, which is another factor in the “global weirding” phenomenon. For the degassing experiment however, if the roasted beans are sealed in a jar with some water, appreciable CO2 degassing will lead to the water becoming acidic, something that is easily measurable.

Experiment 1 – Red Cabbage, Do the coffee beans really degas CO2?

red cabbage, acidity, indicator, natural indicator, coffee bean degassing

The colours of the red cabbage liquid on tissue. Control sample is on the left, light roast in the middle, dark roast on the right

An acidity indicator that you may well have in your kitchen is red cabbage. Liquid extracted from red cabbage is initially purple but will turn blue in the presence of an alkali or red if it is exposed to an acid. For the experiment, three (identical) jars were prepared each containing 60 ml of red cabbage indicator and three (identical) shot glasses. Each shot glass contained either 10g of dark roast, 10g of light roast or nothing (as a control). The coffee beans were kept dry and out of the water by placing them in the shot glasses. The jars were closed, sealed with sellotape and then left. On opening the jars, (approximately 96h after roasting) the two that had contained the coffee beans had turned red (indicating acidity) while the control jar remained purple – see pictures. It is a pretty way of showing the acidification of the water by carbon dioxide and confirms that the beans are degassing. To establish the duration of degassing, it would be necessary to refresh the red cabbage liquid and measure for a further period of time.

Experiment 2 – testing the pH more systematically.

I headed off to a pet shop to get a pH indicator used by people who keep fish (Nutrafin Test). As with experiment 1, the coffee (10g) was sealed in jars (with 30 ml of water) together with a control. When the jars were first opened (at the same time as the red cabbage jars), the jars containing the coffee showed really low (acidic) pH values (approx 6.0 – 6.5). The control water was neutral or slightly alkali (approx 7.5). The water in each jar was then emptied, the jar rinsed and the water replaced with 30 ml of fresh water which was then sealed in the jar, again for 48h. The picture below shows the evolution of the pH with time (measured as hours after roasting) for the jars containing both roasts. The jar containing the dark roast showed a reduced acidity by 192h (8 days) after roasting (the test tube in the picture is greener), compared with about 288h (12 days) for the light roast. Even after this amount of time however, the water was still becoming slightly more acidic than the control, indicating that the beans were still degassing a little.

pH testing, coffee bean degassing

Testing the pH of the water exposed to the coffee bean degassing. The light roasted beans are on the top row, the dark roast on the bottom row. The ‘hours’ is the number of hours after roasting. The pH is measured by comparing the colour of the liquid in the tube to the colour chart.

Experiment 3 – using a bubble system to ‘catch’ the CO2

A third experiment to try to ‘catch’ the CO2 degassing from the beans (in an adaptation of this experiment) sadly did not work on either occasion that I tried it. If you try it and get it to work with with equipment that you can find around the house, please let me know via the comments section below.

Conclusions:

The coffee tried here, Daterra, Bourbon Yellow, degassed significantly for 6 days after the roasting date. The time over which the beans degassed, was dependent on the roast type, with the dark roast degassing for less time, consistent with the thoughts expressed here. Degassing certainly continued for many days after the critical ’72’ hours. Even 10 days after roasting, some degassing was still occurring. To be pedantic about things, the gas was not identified in these experiments. However, the acidification of the water in proximity with the coffee beans is consistent with the gas being CO2.

Please do try this at home and send me your results and pictures. Let me know what you find out, whether you use red cabbage or a bubble system that works. One thing that these experiments did not do at all of course was monitor how the beans tasted over a similar time frame to the degassing experiment. Perhaps you have thoughts on this. Please send your comments via the form below, comments are moderated but will (hopefully) be approved pretty quickly after you submit them.

Thanks again to Roasting House for being very efficient about sending me freshly roasted coffee and also to Tyla for helping to independently test the red cabbage experiment.