The Compostable Cup Trials



Some years back, I ran across some compostable water bottles at a Starbucks in Seattle and, because of the skepticism deeply embedded in  ProfessorRoush’s academic soul, I thought it would be a neat idea to try to bring them back in my luggage and test their compost-worthiness at home.  Unfortunately, the TSA must have deemed the empty bottles in my checked bags as a potential terrorist threat because the bottles were not in my suitcase upon my arrival at home.

I was more fortunate last year when I ran into these certified compostable cups at a pizza parlor in Fort Collins, and I was able to ultimately get them into my 65 gallon Lifetime tumbling compost bin by sneaking them home in my car past the marijuana-alert sentries on the Kansas border.

These Eco-Product cold cups are, as printed on the cups, certified by the BPI, or Biodegradable Products Institute, to be compostable in a municipal or commercial composting facility.  The BPI is a “multi-stakeholder association of key individuals and groups from government, industry and academia” that tests products by written ATSM standards and certifies them. Materials tested by the BPI must include the ability to “biodegrade at a rate comparable to yard trimmings, food scraps and other compostable materials, such as kraft paper bags,” and they must “disintegrate, so that no large plastic fragments remain to be screened out.”


I placed the new cups pictured in the top photo into my tumbling compost bin on 5/26/2014, along with mature compost and grass clippings.  You can see immediately above this paragraph several periodic photos taken over last summer, a time span when numerous additions of kitchen scraps, grass clippings, other organic materials, and water were composted in the pile alongside these cups.  The cups did not disintegrate, as you can see, although they flattened and tore, probably from the repeated tumbling alongside wet and heavy clumps of compost.  The organic materials in the bin repeatedly became decent, black homogeneous compost with which any gardener would be happy.


This week, almost 11 months after the start of the experiment, I again opened the compost bin and found the cups as shown.  Now, in fairness, I should note that the BPI website states clearly that these products are not meant for home compost piles, but only for “well-managed municipal and commercial facilities.”  Home composters “typically do not generate the temperatures needed to assure rapid biodegradation of this new class of materials. For this reason, claims are limited to larger facilities.”

That’s all well and good, friends—I can accept that ProfessorRoush is likely a terrible composter—but shouldn’t we at least expect that now, 11 months later, the ink would faded and illegible?

Furthermore,  while I’m on a rant, what exactly constitutes an “acceptable municipal facility?”  Does my local county recycling facility, which routinely composts leaves and other materials, qualify?  It isn’t listed at the website printed on the cups, nor is any other facility within 50 miles of me.  How many of these cups would actually make it into a “well-managed commercial facility” anyway, rather than just being tossed into the restaurant waste cans with all the other debris and taken to the usual county shredding facilities?  How much more energy and chemical processing is involved in making these cups over the standard red plastic cups that we love to make so much fun of?  Which is more likely to be recycled and have the least long-term environmental impact?  Is this merely more marketing misinformation to muddle the minds of the masses?

I can’t help thinking that while compostable cups make us all feel good, this whole certification system seems designed just to keep us from noticing the man behind the curtain while we slurp the Koolaid of environmental ecstasy.  It is only a matter of time before we’ll hear offers for a free carton of these cups with every thousand carbon credits we purchase.


  1. Well, Professor – being a bit of a natural skeptic my own self, I kind of smell a corporate rat here. Sort of like the way that companies try to increase their market share of, say, breakfast cereal by slapping the USDA organic logo on the box. Meaningless, but it manages to fool a lot of the people. They’re able to feel good about themselves without making much effort. I think that may apply in this instance.

    • That example does not make sense. “Organic” is certified. “Compostable” is not.

      BTW those red plastic cups can be recycled through a company called “TerraCycle” where you mail it away (free). Also lots of other stuff.

  2. On the other hand, do you really want those chemicals and polymers, etc. as one of the ingredients in your earthy, organic compost? It is similar to those polymer crystals people put in their potting mix to hold water. That stuff eventually breaks down and now those artificial ingredients are part of the potting mix.

    • That’s a good point, Jan. I guess I was naïve enough to think that anything that would break down in a compost pile would be “organic.” Heck, for all I know, I guess the ink could be lead-based.

      • My first thought was the same as Jan’s – what are the cups made from and do I want it in my compost? I volunteer at local farmers market at their zero waste kiosk helping sort the trash into landfill, recycle, and compost bins. Generally these cups go in the recycle bin but I’ll ask the composting group if they have tried to compost them. I’m curious now.

  3. I am not surprised they wouldn’t break down in a tumbler. My experience with tumblers is that they are slow. (I am a really bad composter.) But the whole thing seems so futile–if you’re drinking so much takeout bev that you accumulate these cups, then you should just buy a thermos/drink bottle from the place that you can use for months/years.

    • That may be for most. I’ve always thought this commercial one was pretty fast, or at least it is on grass clippings and kitchen scraps. And if the main complaint is that they don’t reach a high enough temperature? This thing is black, double-walled. I imagine it’ll hit 140 just sitting in the Kansas sun on a calm June day without any internal decomposition going on at all. I could probably cook meat inside it during August.

  4. I put a “compostable” sun chips bag in my compost bin over 3 years ago. It’s still there.

    • Same here. What a scam. Some of those biodegradable pots for seedlings too. For these reasons, I don’t trust any packaging that tells me it’s biodegradable or compostable. Just not believable.

    • I have a compostable fork and spoon in my pile going on 4 years now. By the way they looked last year, I imagine they are still in there.

    • that’s funny. I too put a sun chips bag in my composter and left it there for three years with absolutely no change to the bag at all! Noisy and not degradable! lack of success all around!

  5. I have cut up a “compostible” cup and then some utensils that I have come across. Both have “disappeared” in the compost over the year… but I will say that the parts that were exposed to the sun became brittle very quickly….. vs the parts that I purposefully moved to the center of the 4×4 compost pile.

    PS… I can still hear the sound of those old Sun Chips bags….

  6. Thank you for confirming my doubts about just how “compostable” some of those “natural plastics are.

    Given what will pass the USDA as “organic” keeps me from believing the item is organic unless it’s passed the Oregon Tilth or CCOF tests. When I found out what can pass as “whole grain” or even “whole wheat” flour, steam came out of my ears.

    I do carry my own drink tumblers, and seldom am stuck having to use a disposable cup. I need to have water in the car at hand at all times: if I cough too long or too hard, I will have a foul mess to clean up. A couple of swallows of nice cold water from an insulated tumbler stops the upward movement, and the cough. The cough is year round and connected to allergies. Very dull.

    This week at a dance festival, I’ll also be carrying my own bowl-shaped storage container to put festival food in, and I’ll have my own collapsible utensils–usually I’ll have a Swedish-made Spork with a bit of a serrated edge that can’t cut for anything, but my troupe leader gave me a set that can go back in its container when you’re through, instead of a baggie. I’m looking forward to the ginger lemonade there, too.

  7. Oh, I don’t know…we have a pilot program in my town for municipal composting, and I’ve seen it have a real impact on the waste stream. Our grocery co-op hosts an annual meeting/picnic for over 4000 people, and compostable products like those cups cut the amount of landfill-destined garbage down to almost nothing; it all heads to a commercial composting facility.

    We’re starting to compost in the schools as well. School lunches produce a shocking amount of plastic, and just think about how much food kids pitch at lunchtime; imagine turning all that waste into compost and methane energy instead!

    I’m not surprised the mutant corn-product isn’t breaking down in your backyard, but on an industrial scale, I think its promising…

  8. My wife and I pissed off a TON of Cornhusker football fans last year. They release thousands of balloons after the first touchdown of every home game. Theoretically, these balloons are biodegradable (even the athletic director gave us the standard corporate spiel). After nearly two years ours is still intact. Lots of wildlife choke to death on balloons. Oh, the hate mail and threats we received for insinuating a “tradition” was not in the best interest of proud Nebraskans who theoretically cherish their state and its natural wonders. (I teach this post my wife wrote in my writing classes — it creates good debate and wins over some).

    • Oh, but Benjamin, it’s Cornhusker tradition. Living there in the heart of it all, you are less safe than if you drew a picture of the Prophet Mohammed and carried it down the streets of Mecca!

  9. Thank you, Professor. That ’s the kind of rant I like to read. It’s all too easy to drink the kool-aid.

  10. wow… those are some posts you have there on that huskers posting. I wonder what those same people would say if you walked over to there house with a bunch of huskers posters, huskers napkins, huskers cotton t-shirts and just dumped them on their lawn…. with a sign saying … it’s okay … they are biodegradable!

  11. Compostable Easter grass. I hate plastic Easter grass. It gets everywhere when you store the kids’ baskets for the rest of the year. When I saw some labeled as “compostable” I was happy to give it a try, thinking I could put it in the tumbler and be done with it. Six years later, and I’m still picking little ribbons of bright green plastic out of my garden.

  12. I just found your blog and love it!
    Regarding the compostable plastic I agree with some other comments about not wanting the chemicals in my compost. I think the thing is that we are so overwhelmed with messages, entertainment, and constant slogans that we “buy” buzz words even though they mean little to nothing – ala “natural.” My concern is that while these plastics would eventually break down to where I couldn’t see pieces – what sort of chemical will my plants, and then I & my family, be eating. I think it’s a load of crap.

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