Basil is probably one of the easiest herbs to grow in a container, and gives you a lot of bang for your buck. In fact, you may have too much bang for your buck (so much basil you can’t use it all at once). As things wind down for the season, preserving what you’ve harvested is a great way to have access to the high quality herbs you became accustomed to during the summer.
There are several methods of preserving basil, but these three are–I think–the easiest and most effective. It goes without saying that regardless of the method you choose, you should start with clean, dry leaves.
Freezing basil produces (in my opinion) the best results, as the basil is later suitable for using both cooked and fresh. Creating a paste with a small amount of oil has worked best for me. To do this, place the leaves and tender stems into the food processor and turn it on. Slowly drizzle olive oil (or a flavorless vegetable oil if you’re preserving a flavored basil) into the processor’s bowl until a thick paste forms. There should be more basil than olive oil (about a 3:1 or 4:1 ratio). Place the paste into ice cube trays and freeze. When the cubes are completely frozen, you can pop them out and put them in freezer safe storage containers.
Basil stored this way can be kept for up to two years.
While this may seem strange to modern folks (at least it did to me), salt was a common method of food storage “way back when.” To preserve your basil harvest in salt, simply pour a 1/4 inch of salt into the bottom on a glass pint jar. Then add a layer of basil leaves. Repeat until the jar is full. Seal the jar with a lid and store in the fridge.
Basil stored in salt will last for about 6-9 months. The salt will not take on a basil flavor, but you can still use it as you normally would.
Dried basil is best when the leaves are kept whole. When the leaves are crumbled, they lose some of the essential oils that make basil taste and smell so great. The easiest way to do this is to hang stems upside down for a week or more, until they are completely dry. Then use a pair of scissors to snip the leaves off of the stem, placing them directly into a wide mouth jar.
Dried basil should be stored in a closed jar, away from heat and light. It will keep for about a year.