When I recently posted in a New York Times blog that biodegradability isn’t what it seems, and on Packaging Digest that we should be careful with biodegradable plastics and incineration habits, I got a few reminders that some compostable plastics are not made of PLA (polylactic acid), which is the most common polymer used for biodegradable plastics. Some are made of different types of biodegradable plastic that are more easily compostable in the backyard. This is very true, and I think my question has now become, which is the more sustainable of the two options: recyclable plastics, or biodegradable plastics? We already know that incineration is not the best method for disposal. While it is often referred to as “waste to energy,” it might as well be “waste to air pollution” because it adds to the carbon emissions (already a problem) and introduces other toxins to the atmosphere. I have always believed that recycling is the best way to go because it makes the most of the energy consumed to make the product. Composting is a great option, and is appropriate at times, don’t get me wrong. But let’s face it–it takes much longer and much more energy to make the majority of our plastics than the time and energy it takes to use that plastic. Think about a plastic cup: manufacturing the cup, and using the energy to make it, takes longer than it does to drink a soda out of that cup. In order to not waste the energy expended in manufacturing, the longer the life of the product, the better. It doesn’t make sense to throw out a pair of shoes that are barely worn, and same goes for a plastic.