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The Compostable Burn Test: Is your compostable cutlery really compostable?

There are utensils on the market that are advertising as compostable cutlery and are being sold at very affordable prices.  Unfortunately there seems to be little regulation around the labeling of products and these utensils do not appear to be compostable.

There are utensils on the market that are advertising as compostable cutlery and are being sold at very affordable prices.  Unfortunately there seems to be little regulation around the labeling of products and these utensils do not appear to be compostable.

GreenHome’s range of cutlery is embossed Compostable, plant-based and 100% compostable.  

We understand that compostable cutlery comes at a premium compared to plastic cutlery.  We’ve asked our suppliers about the more affordable “compostable” options and have been assured that it isn’t possible to make 100% plant-based cutlery for the lower price.  We’d prefer to continue bringing you 100% plant-based cutlery at the best price we can find.

Close up of a GREEN HOME spoon with the word Compostable embossed on the handle

How can you tell if what you are buying is the real deal?  Well, firstly, compostable cutlery looks different to cutlery made from petroleum-based materials. When you compare the two you will notice that compostable cutlery is pearly white and embossed Compostable. Cutlery made from a mix of petroleum-based plastic and plant starch more yellow in colour and does not carry the embossing mark.  The best way to determine whether what you are buying is really made from 100% pure plant starch; is to perform the burn test.

1. The Burn Test

If you’re convinced that the cutlery you’ve bought is compostable, burn it and see what happens. You’re looking out for two things, first the colour of the smoke and secondly the smell of the smoke.

A GREEN HOME Fork burning, with a clear flame and clear smoke

If your knives and forks are bona fide compostable and made from plants they will burn with a white smoke and a very light burning smell.

Burning cutlery with black smoke coming off

If your knives and forks are petroleum-based, they will burn with a black smoke and give off a strong chemical smell.

Cutlery burning with light black smoke

Knives and forks made from a mix of plant starch and petroleum burn with a light black smoke and give off a slight chemical smell.

2. The Bend Test

This is a simpler but not as accurate as test number 1.  All you need to do is bend your cutlery and see what happens.

If your knives and forks are bona fide compostable and made from plants they are most likely brittle and will snap in two when you try to bend them.

If your knives and forks are petroleum-based, they are more likely to be flexible and will bend back over themselves. Knives and forks made from mixed raw materials respond in a similar fashion when bent.

What do you think the pseudo-compostable cutlery is made from?

We suspect the cutlery is made from part plant-based and part petroleum-based degradable plastic. Adding these utensils to a compost heap will give the appearance of biodegrading but in fact the plastic is just breaking down into smaller pieces which is not good in a compost heap.

If you do perform these tests, please let us know the results and observations you make regarding the different materials.  Happy burning!  Remember to keep it safe, don’t test flammable objects such as curtains or serviettes, tie your hair up and don’t let your kids do it alone.