If you love and make pesto—more than you can use at one meal—you know that storing it can pose problems. The miracle of zipper-lock plastic bags comes to the rescue.
Here’s how it works: Put your pesto in a bag (I use a jar funnel to ease the task) and flatten it out to remove the air and to create a sort of thin slab of pesto. Seal the bag, and freeze it.
Then, when you want to use some pesto, you can break off as much pesto as you need, reseal the bag, and toss it back in the freezer. The pesto stays fresh and safe and maintains its vibrant color.
The traditional recommendation is to store pesto in the refrigerator with a thin coating of olive oil to keep air out (and, thereby, keep the basil from turning dark and ugly). That works OK if you’re going to use the balance in short order. If you aren’t, there’s a bit of a botulism hazard for garlic stored without air for more than a few days.
Botulism aside, those of us who (a) make large portions of pesto or (b) use small bits of it at a time need something that lasts longer than the oil-covering method. The plastic bag provides the perfect solution.