Our compost bin testing methodology
We spoke with Rick Carr, Farm Director at Rodale Institute in Kutztown, PA, and Dr. Paul Voroney, Professor of Environmental Sciences at the University of Guelph, in order to learn the finer points of composting.
In suburban and rural settings, a composting station is often a more realistic option. You’ll still want a small kitchen bin (up to a couple of gallons) and a larger five- or 10-gallon bucket just outside, but a production station becomes necessary for processing and generating fertile soil. There are several ways of doing this, from a hole in the ground to a worm bin.
It also depends on what you’re going to be composting. Some of us don’t have the space reasonable for composting raw animal products, bones, and other things that get a little too gross for comfort. It can be done, though. “In my house, we compost anything that can be composted,” says Carr.
We tested five bins in our home and measured their effectiveness based upon various criteria. We have recommendations depending upon how much compost you want to store within your kitchen and how involved you want to get within the process. Michelle Ullman contributed to an earlier version of this guide.
When it came time to do our testing, we gathered five compost bins and filled each with a mixture of plant, meat, and fish scraps, separating layers with shredded paper and leaving them in the kitchen for a few days to see how bad the smell got. Within two days, all of the bins began to emit a rotten fish smell, and fruit flies were rampant throughout the kitchen. This was more or less expected.
We then kept meat and fish out of the equation and took note of which bins seemed to gather fruit flies. We were only able to isolate two that didn’t: the Oxo Good Grips Easy-Clean and the SCD Probiotics.
While bins with compost filters might have helped keep odors at bay, there was no shortage of fruit flies finding their way in and out. While we still recommend a charcoal-filter option, keep in mind that there’s a good chance you’ll still end up with fruit flies.
We found that the best way to eliminate fruit flies was through anaerobic composting with bokashi, which is the process of using anaerobic bacteria to jump start the composting process.
What we considered along the way:
Smell: We put everything that is compostable into each bin to see if any of the bins managed to conceal the most putrid smells, but as expected things got utterly foul by day two. When we conducted a second round of tests without any animal byproducts (save for eggshells), the smells were much less effusive, but the bins that did best were the ones without vents.
Size: For a compost bin to do its job within a kitchen, it has to fit on the counter or underneath the kitchen sink. For this reason, we didn’t test anything too small (less than one-half of a gallon) or too large (larger than five gallons). Whether you’re looking for something for your countertop or beneath your sink, all of our picks will fit the bill in that regard.
Cleanliness: Because no one wants to find themselves elbow-deep in rot, a compost bin needs to be easy to clean. All of the bins we tested were relatively easy to clean, but some were easier than others. Many come with removable liners, and while that makes cleaning a little more convenient, it didn’t end up being a deal breaker. If you use compostable paper bags as liners, they’ll be nearly as effective.