It has been established that I have a basil ‘problem,’ but it isn’t going to last forever. Basil will only be in season for a few more weeks, so I need to preserve as much of it as I can now!
Basil gets its flavor from some very volatile aroma compounds that are easily lost, so you need to be gentle as you work with it. Don’t even think about drying the basil; it will lose all of its flavor and you’ll be stuck with some crumbling, flavorless leaves.
Don’t plan on just sticking the whole bundle of basil in the fridge, either; basil comes from a warm climate, and doesn’t do well in the cold. The basil will turn black and unappealing quickly.
Instead, try one of these methods to prolong your basil’s shelf life:
For Immediate Use:
1. In a jar on a sunny windowsill. Cut the stems of the basil at a diagonal and place in a jar of water somewhere sunny and warm. Stored this way, the basil will stay fresh for up to 1 week. Pluck the leaves of basil as you need them, and return the unused portion to the jar.
With this method, you want to make sure that only the stems are wet; the leaves should not be touching the water. The easiest way to achieve this is to cut the stems long, then prop the leaves up on the edge of the jar to keep them exposed to the air and out of the water.
Make sure you cut the stems immediately before putting the basil in the water, even if this means re-cutting the stems. The cuts will start to seal themselves up quickly when exposed to air, a little like a scab. If you don’t get them in the water before this seal begins to form, the stems won’t absorb water as well and the basil will wilt and go bad much more quickly.
2. As pesto. Grind fresh basil leaves with olive oil, pine nuts, garlic, Parmesan cheese and lemon juice. I don’t typically use a recipe for this — just taste as I go until it is creamy without being oily — but this recipe can serve as a good starting point for you. Covered and refrigerated, pesto will last about 2 weeks.
3. In oil. Wash and dry whole leaves of basil. Pack the basil in the bottom of a pint-sized glass jar and cover with extra virgin olive oil. Make sure the basil is covered completely. Store the oil in an airtight container towards the back of your refrigerator, where it will get less exposure to light, as light causes the oil to deteriorate more quickly. You may choose to use either the whole leaves or the basil-flavored oil in your cooking. Basil in oil will last for 2-3 weeks in the refrigerator. Herbs in oil should NOT be stored at room temperature, due to the risk of botulism.
For Long-Term Storage:
1. As pesto. Prepare the pesto just as you would for immediate use, but leave out the cheese. Pour into a freezer-safe container, leaving about 1/2″ of space on top for it to expand as it freezes, and cover the top with a film of olive oil. The olive oil will serve as a barrier between your pesto and the air, so the basil won’t oxidize and turn an unpleasant black color. If you decide to skip the olive oil, the pesto will still be perfectly safe to eat, but it will not be a pretty fresh green color and may experience a bit of freezer burn. Add the cheese when you defrost the pesto for use. The frozen pesto will be good for about one year.
2. In oil. In a blender or food processor, grind the basil with just enough olive oil to create a thick slurry. Scrape the basil into an ice cube tray and freeze. When the basil cubes are frozen, pop them out of the tray and store them in an airtight freezer container. They will last this way for approximately one year.