I feel like the Herb-Savor ($29.99 at Spoon Sisters) by Prepara is one of those gadgets that I've seen everywhere and never really paid much attention to. It looks gimmicky, and how well could a plastic casing really work when it comes to prolonging the life of my quick-to-wilt herbs? Well, given that my patio herb garden (aka the pot of basil I once grew) is out of commission in the winter, and that I'm thereby forced to buy bunches of herbs that I can never consume within a week, I figured I had nothing to lose by testing it out.
As it turns out, my bias was completely unfounded. I did my best to be scientific about this process, but Kenji I am not. Three times, I bought herbs (different kinds, cilantro, parsley, and basil, for comparison), and stored half in a plastic bag in the fridge drawer. The other half went into the Herb Savor, et voilà! My control and experimental groups were set for action.
For each attempt, my Herb-Savor herbs outlived my fridge drawer's by quite a bit. The packaging advertises that the Herb Savor will extend their lifespan by 3 weeks, which it did, but in one instance, my protected parsley survived its relatively neglected counterpart by a full six weeks.
It's a simple gadget, really: a plastic case with "breathing holes" holds your herbs along with a metal mesh screen. A plastic well holds enough water to keep your herbs going, and plugs up to prevent spillage. Overall, it's aesthetic, practical, and fits easily in the fridge, whether on the shelf or in the door. Note that the fridge is a key part of success here —herbs kept outside of the fridge will last less time than those you keep inside it, even without the Herb Savor.