The countertop kitchen composter is a lovely vision. Instead of a smelly bucket of vegetable scraps and coffee grounds breeding fruit flies on your counter or attracting rats to your backyard, you could just put it all into a nifty electric gadget, and at some undetermined point in the future, you'll have a bountiful supply of nutrient-rich compost to use in your garden.

Unfortunately, none of the more popular electric machines quite do this. Even though some of these devices are marketed as “composters" and have instruction booklets and apps detailing all the ways in which one can use compost, the vast majority of kitchen composters are just going to grind up and dry your food scraps.…